Virtual generated columns

From 1df68f38a7160fff4e48821c3a0419882a2d2523 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 29 Apr 2024 09:46:43 +0200
Subject: [PATCH v1 1/5] Rename regress test generated to generated_stored

This makes naming room to have another test file for virtual generated
columns.
---
 .../regress/expected/{generated.out => generated_stored.out}    | 0
 src/test/regress/parallel_schedule                              | 2 +-
 src/test/regress/sql/{generated.sql => generated_stored.sql}    | 0
 3 files changed, 1 insertion(+), 1 deletion(-)
 rename src/test/regress/expected/{generated.out => generated_stored.out} (100%)
 rename src/test/regress/sql/{generated.sql => generated_stored.sql} (100%)

diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated_stored.out
similarity index 100%
rename from src/test/regress/expected/generated.out
rename to src/test/regress/expected/generated_stored.out
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 969ced994f4..d4bbc0db25b 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -66,7 +66,7 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated join_hash
+test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
 # ----------
 # Additional BRIN tests
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated_stored.sql
similarity index 100%
rename from src/test/regress/sql/generated.sql
rename to src/test/regress/sql/generated_stored.sql

base-commit: c37267162e889fe783786b9e28d1b65b82365a00
-- 
2.44.0

From 313544d8ea4ba22433bbb9501a0252262c916ffc Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 29 Apr 2024 09:46:43 +0200
Subject: [PATCH v1 2/5] Put generated_stored test objects in a schema

This avoids naming conflicts with concurrent tests with similarly
named objects.  Currently, there are none, but a tests for virtual
generated columns are planned to be added.
---
 .../regress/expected/generated_stored.out     | 71 ++++++++++---------
 src/test/regress/sql/generated_stored.sql     |  8 ++-
 2 files changed, 43 insertions(+), 36 deletions(-)

diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 44058db7c1d..dd74a1a9f0b 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -4,9 +4,12 @@ SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT
 ----------+---------+--------------
 (0 rows)
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -15,14 +18,14 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                            Table "public.gtest1"
+                    Table "generated_stored_tests.gtest1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -270,7 +273,7 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                           Table "public.gtest1_1"
+                   Table "generated_stored_tests.gtest1_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -312,7 +315,7 @@ ERROR:  column "b" inherits from generated column but specifies identity
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                                Table "public.gtestx"
+                                        Table "generated_stored_tests.gtestx"
  Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
 --------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
  a      | integer |           | not null |                                     | plain   |              | 
@@ -348,7 +351,7 @@ NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                           Table "public.gtest1_y"
+                   Table "generated_stored_tests.gtest1_y"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -523,7 +526,7 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-              Table "public.gtest10"
+      Table "generated_stored_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
@@ -622,7 +625,7 @@ CREATE INDEX gtest22c_b_idx ON gtest22c (b);
 CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
 CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
 \d gtest22c
-                           Table "public.gtest22c"
+                   Table "generated_stored_tests.gtest22c"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -726,7 +729,7 @@ CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
 CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
 \d gtest23b
-                           Table "public.gtest23b"
+                   Table "generated_stored_tests.gtest23b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -805,7 +808,7 @@ DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -814,7 +817,7 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -823,7 +826,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -855,7 +858,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -865,7 +868,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -874,7 +877,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -883,7 +886,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -902,7 +905,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -912,7 +915,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -921,7 +924,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                         Table "public.gtest_child2"
+                 Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -930,7 +933,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                         Table "public.gtest_child3"
+                 Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -987,7 +990,7 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                         Table "public.gtest25"
+                                 Table "generated_stored_tests.gtest25"
  Column |       Type       | Collation | Nullable |                       Default                        
 --------+------------------+-----------+----------+------------------------------------------------------
  a      | integer          |           | not null | 
@@ -1011,7 +1014,7 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                                Table "public.gtest27"
+                        Table "generated_stored_tests.gtest27"
  Column |  Type   | Collation | Nullable |                  Default                   
 --------+---------+-----------+----------+--------------------------------------------
  a      | integer |           |          | 
@@ -1037,7 +1040,7 @@ ALTER TABLE gtest27
   ALTER COLUMN b TYPE bigint,
   ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1051,7 +1054,7 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1079,7 +1082,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1101,7 +1104,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1120,7 +1123,7 @@ SELECT * FROM gtest29;
 (4 rows)
 
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1129,7 +1132,7 @@ SELECT * FROM gtest29;
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  b      | integer |           |          | 
@@ -1142,7 +1145,7 @@ CREATE TABLE gtest30 (
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 \d gtest30
-              Table "public.gtest30"
+      Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1150,7 +1153,7 @@ ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-             Table "public.gtest30_1"
+     Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1167,7 +1170,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                            Table "public.gtest30"
+                    Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1175,7 +1178,7 @@ ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                           Table "public.gtest30_1"
+                   Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1336,14 +1339,14 @@ CREATE TABLE gtest28a (
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                           Table "public.gtest28a"
+                   Table "generated_stored_tests.gtest28a"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
-                           Table "public.gtest28b"
+                   Table "generated_stored_tests.gtest28b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index cb55d77821f..c18e0e1f655 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -2,12 +2,16 @@
 SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
 
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
+
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
-- 
2.44.0

From 6653f72f7990488a5958451666b81c105d7f91de Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 29 Apr 2024 09:46:43 +0200
Subject: [PATCH v1 3/5] Remove useless initializations

The struct is already initialized to all zeros right before this, and
randomly initializing a few but not all fields to zero again has no
technical or educational value.
---
 src/backend/utils/cache/relcache.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index cc9b0c6524f..b09f6a90e44 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -535,8 +535,6 @@ RelationBuildTupleDesc(Relation relation)
 
 	constr = (TupleConstr *) MemoryContextAllocZero(CacheMemoryContext,
 													sizeof(TupleConstr));
-	constr->has_not_null = false;
-	constr->has_generated_stored = false;
 
 	/*
 	 * Form a scan key that selects only user attributes (attnum > 0).
-- 
2.44.0

From d2325a73711d77e5bd0bdc3df234efac229cb948 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 29 Apr 2024 09:46:44 +0200
Subject: [PATCH v1 4/5] Remove useless code

BuildDescForRelation() goes out of its way to fill in
->constr->has_not_null, but that value is not used for anything later,
so this code can all be removed.  Note that BuildDescForRelation()
doesn't make any effort to fill in the rest of ->constr, so there is
no claim that that structure is completely filled in.
---
 src/backend/commands/tablecmds.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 313c782cae2..958007ca316 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1272,7 +1272,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
  *
  * Given a list of ColumnDef nodes, build a TupleDesc.
  *
- * Note: tdtypeid will need to be filled in later on.
+ * Note: This is only for the limited purpose of table and view creation.  Not
+ * everything is filled in.  A real tuple descriptor should be obtained from
+ * the relcache.
  */
 TupleDesc
 BuildDescForRelation(const List *columns)
@@ -1281,7 +1283,6 @@ BuildDescForRelation(const List *columns)
 	AttrNumber	attnum;
 	ListCell   *l;
 	TupleDesc	desc;
-	bool		has_not_null;
 	char	   *attname;
 	Oid			atttypid;
 	int32		atttypmod;
@@ -1293,7 +1294,6 @@ BuildDescForRelation(const List *columns)
 	 */
 	natts = list_length(columns);
 	desc = CreateTemplateTupleDesc(natts);
-	has_not_null = false;
 
 	attnum = 0;
 
@@ -1339,7 +1339,6 @@ BuildDescForRelation(const List *columns)
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
 		att->attnotnull = entry->is_not_null;
-		has_not_null |= entry->is_not_null;
 		att->attislocal = entry->is_local;
 		att->attinhcount = entry->inhcount;
 		att->attidentity = entry->identity;
@@ -1351,24 +1350,6 @@ BuildDescForRelation(const List *columns)
 			att->attstorage = GetAttributeStorage(att->atttypid, entry->storage_name);
 	}
 
-	if (has_not_null)
-	{
-		TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
-
-		constr->has_not_null = true;
-		constr->has_generated_stored = false;
-		constr->defval = NULL;
-		constr->missing = NULL;
-		constr->num_defval = 0;
-		constr->check = NULL;
-		constr->num_check = 0;
-		desc->constr = constr;
-	}
-	else
-	{
-		desc->constr = NULL;
-	}
-
 	return desc;
 }
 
-- 
2.44.0

From 687cb97094ba038cc4d59f1a6fb04492efaf6a46 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 22 May 2024 10:44:52 +0200
Subject: [PATCH v1 5/5] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  10 +
 src/backend/commands/tablecmds.c              | 104 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/analyze.c                  |   8 +
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_clause.c             |   4 +
 src/backend/parser/parse_relation.c           |   9 +-
 src/backend/parser/parse_utilcmd.c            |  40 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 164 +++-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   3 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/parser/parse_node.h               |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |   6 +-
 ...rated_stored.out => generated_virtual.out} | 790 ++++++++----------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |   2 +-
 ...rated_stored.sql => generated_virtual.sql} | 280 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 53 files changed, 1184 insertions(+), 710 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (70%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (74%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60a..7e0b09e279b 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b5..186dda1e8d0 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 078b8a966f8..7a3e71c07b4 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7215,65 +7215,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7281,28 +7284,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 09ba234e43d..1fc28b3e264 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1806,12 +1806,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 15f6255d865..839b1ddb682 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1317,8 +1317,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 6aab79e901c..d800f538146 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 5d352abf991..f89f85fb195 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -271,6 +271,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -283,10 +288,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index f19306e7760..6bca32ff383 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2e..5953d24ae8f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 309389e20d2..c7c991ad57f 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..fd56e472d88 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,11 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +274,11 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 958007ca316..fa8fc3bde56 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2939,6 +2939,12 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname)));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3210,6 +3216,12 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname)));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -5998,7 +6010,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7683,6 +7695,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 const char *colName, LOCKMODE lockmode)
 {
 	HeapTuple	tuple;
+	Form_pg_attribute attTup;
 	AttrNumber	attnum;
 	Relation	attr_rel;
 	ObjectAddress address;
@@ -7699,8 +7712,8 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				(errcode(ERRCODE_UNDEFINED_COLUMN),
 				 errmsg("column \"%s\" of relation \"%s\" does not exist",
 						colName, RelationGetRelationName(rel))));
-
-	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
+	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = attTup->attnum;
 
 	/* Prevent them from altering a system attribute */
 	if (attnum <= 0)
@@ -7709,12 +7722,20 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
-	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
+	if (!attTup->attnotnull)
 	{
-		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = true;
+		attTup->attnotnull = true;
 
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
@@ -7725,7 +7746,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 		 * already found that we must verify some other not-null constraint.
 		 */
 		if (!tab->verify_new_notnull &&
-			!NotNullImpliedByRelConstraints(rel, (Form_pg_attribute) GETSTRUCT(tuple)))
+			!NotNullImpliedByRelConstraints(rel, attTup))
 		{
 			/* Tell Phase 3 it needs to test the constraint */
 			tab->verify_new_notnull = true;
@@ -8307,7 +8328,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8464,17 +8496,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -9696,6 +9741,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11659,7 +11717,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12700,8 +12758,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -17858,8 +17920,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -17941,9 +18006,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 95de402fa65..92c8c9824e2 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2501,6 +2511,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3058,6 +3070,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3488,6 +3502,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6593,3 +6608,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 852186312c5..3eeddc81311 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2001,6 +2001,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 4d7c92d63c1..d82170785bf 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1748,6 +1748,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2295,7 +2296,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 28fed9d87f6..01dedbfc396 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -562,6 +562,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -988,6 +989,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1453,6 +1455,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1679,6 +1682,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1930,6 +1934,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2404,6 +2409,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2471,6 +2477,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2837,6 +2844,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 4d582950b72..6c80405c48e 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -641,7 +641,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -791,7 +791,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -4025,7 +4025,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -4033,6 +4033,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4079,6 +4080,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17882,6 +17889,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18538,6 +18546,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495b..48524ac3fc2 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e37..b864749f09c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 639cfa443e2..0ae731861a6 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -760,10 +760,36 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
+
+				/*
+				 * TODO: Prevent virtual generated columns from having a
+				 * domain type.  We would have to enforce domain constraints
+				 * when columns underlying the generated column change.  This
+				 * could possibly be implemented, but it's not.
+				 *
+				 * XXX If column->typeName is not set, then this column
+				 * definition is probably a partition definition and will
+				 * presumably get its pre-vetted type from elsewhere.  If that
+				 * doesn't hold, maybe this check needs to be moved elsewhere.
+				 */
+				if (column->generated == ATTRIBUTE_GENERATED_VIRTUAL && column->typeName)
+				{
+					Type		ctype;
+
+					ctype = typenameType(cxt->pstate, column->typeName, NULL);
+					if (((Form_pg_type) GETSTRUCT(ctype))->typtype == TYPTYPE_DOMAIN)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("virtual generated column \"%s\" cannot have a domain type",
+										column->colname),
+								 parser_errposition(cxt->pstate,
+													column->location)));
+					ReleaseSysCache(ctype);
+				}
 				break;
 
 			case CONSTR_CHECK:
@@ -848,6 +874,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index d2b35cfb96d..e44ec8ae644 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 8a29fbbc465..2e5b48a533e 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -89,6 +89,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
 
 
 /*
@@ -973,7 +975,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4341,6 +4344,150 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+static Node *
+expand_generated_columns_in_expr_mutator(Node *node, Relation rel)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		AttrNumber	attnum = v->varattno;
+
+		if (attnum > 0 && TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			node = build_column_default(rel, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rel));
+			ChangeVarNodes(node, 1, v->varno, 0);
+		}
+
+		return node;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_in_expr_mutator, rel);
+}
+
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		return expression_tree_mutator(node,
+									   expand_generated_columns_in_expr_mutator,
+									   rel);
+	else
+		return node;
+}
+
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+};
+
+static Node *
+expand_generated_columns_in_query_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_in_query_mutator, context);
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_in_query_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4396,6 +4543,21 @@ QueryRewrite(Query *parsetree)
 	/*
 	 * Step 3
 	 *
+	 * Expand virtual generated columns.
+	 */
+	foreach(l, querylist)
+	{
+		Query	   *query = (Query *) lfirst(l);
+		struct expand_generated_context context;
+
+		context.rtables = NIL;
+
+		query = expand_generated_columns_in_query(query, &context);
+	}
+
+	/*
+	 * Step 4
+	 *
 	 * Determine which, if any, of the resulting queries is supposed to set
 	 * the command-result tag; and update the canSetTag fields accordingly.
 	 *
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index b09f6a90e44..747322e8136 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -588,6 +588,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index e3240708284..f4b147e48b4 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16004,6 +16004,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index d3dd8784d64..794610ee010 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index f67bf0b8925..7474a481559 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index ddfed02db22..3163fff7db0 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2745,6 +2747,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f7fe834cf45..96167877b75 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -492,6 +492,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9d..1b02128548b 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be345..9611aa82352 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 008ea195095..3bf63ba6133 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 18d14a2b982..fc2399fc978 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3114,6 +3114,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2db75a333a0..e4acf6a5fd9 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 0ed94f1d2fb..4ef8a33858c 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index dd74a1a9f0b..c74d6b4e5cf 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -1091,9 +1091,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 70%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index dd74a1a9f0b..16c8e0ede16 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -273,11 +267,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +290,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +306,41 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +353,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +391,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +413,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +478,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +487,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +502,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +517,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +530,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +538,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +571,139 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+LINE 1: CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENE...
+                                                 ^
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +713,10 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +730,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +767,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +775,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +882,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +937,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +945,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1032,20 +963,19 @@ ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0;  -- error
 ERROR:  generation expression for column "x" cannot be cast automatically to type boolean
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1054,12 +984,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1071,7 +1001,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1082,107 +1012,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1190,7 +1131,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1243,7 +1184,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1253,12 +1194,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1268,8 +1209,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1280,6 +1221,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1293,9 +1236,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1319,14 +1264,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1334,22 +1278,22 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index d4bbc0db25b..fbce82cf7e4 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 4929d373a2f..3ae42a99272 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..03ea1954903 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 74%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..b1c4421c3ed 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -134,22 +134,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +165,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +226,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +241,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +252,168 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +421,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +433,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +464,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +486,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +500,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +512,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +539,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +548,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +559,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +621,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +677,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();
-- 
2.44.0

From 0c2eeb33e0cfc34997ce66233a43363bd34bffde Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 8 Aug 2024 08:13:48 +0200
Subject: [PATCH v2 1/3] Rename regress test generated to generated_stored

This makes naming room to have another test file for virtual generated
columns.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 .../regress/expected/{generated.out => generated_stored.out}    | 0
 src/test/regress/parallel_schedule                              | 2 +-
 src/test/regress/sql/{generated.sql => generated_stored.sql}    | 0
 3 files changed, 1 insertion(+), 1 deletion(-)
 rename src/test/regress/expected/{generated.out => generated_stored.out} (100%)
 rename src/test/regress/sql/{generated.sql => generated_stored.sql} (100%)

diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated_stored.out
similarity index 100%
rename from src/test/regress/expected/generated.out
rename to src/test/regress/expected/generated_stored.out
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 2429ec2bbaa..b0804691f5d 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -66,7 +66,7 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated join_hash
+test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
 # ----------
 # Additional BRIN tests
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated_stored.sql
similarity index 100%
rename from src/test/regress/sql/generated.sql
rename to src/test/regress/sql/generated_stored.sql

base-commit: e56ccc8e4204d9faf86f3bd2e435a0788b3d0429
-- 
2.46.0

From 0645fc149635451df0509191a370dfadf0d2a6a3 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 8 Aug 2024 08:13:48 +0200
Subject: [PATCH v2 2/3] Put generated_stored test objects in a schema

This avoids naming conflicts with concurrent tests with similarly
named objects.  Currently, there are none, but a tests for virtual
generated columns are planned to be added.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 .../regress/expected/generated_stored.out     | 71 ++++++++++---------
 src/test/regress/sql/generated_stored.sql     |  8 ++-
 2 files changed, 43 insertions(+), 36 deletions(-)

diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 44058db7c1d..dd74a1a9f0b 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -4,9 +4,12 @@ SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT
 ----------+---------+--------------
 (0 rows)
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -15,14 +18,14 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                            Table "public.gtest1"
+                    Table "generated_stored_tests.gtest1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -270,7 +273,7 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                           Table "public.gtest1_1"
+                   Table "generated_stored_tests.gtest1_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -312,7 +315,7 @@ ERROR:  column "b" inherits from generated column but specifies identity
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                                Table "public.gtestx"
+                                        Table "generated_stored_tests.gtestx"
  Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
 --------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
  a      | integer |           | not null |                                     | plain   |              | 
@@ -348,7 +351,7 @@ NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                           Table "public.gtest1_y"
+                   Table "generated_stored_tests.gtest1_y"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -523,7 +526,7 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-              Table "public.gtest10"
+      Table "generated_stored_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
@@ -622,7 +625,7 @@ CREATE INDEX gtest22c_b_idx ON gtest22c (b);
 CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
 CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
 \d gtest22c
-                           Table "public.gtest22c"
+                   Table "generated_stored_tests.gtest22c"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -726,7 +729,7 @@ CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
 CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
 \d gtest23b
-                           Table "public.gtest23b"
+                   Table "generated_stored_tests.gtest23b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -805,7 +808,7 @@ DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -814,7 +817,7 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -823,7 +826,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -855,7 +858,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -865,7 +868,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -874,7 +877,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -883,7 +886,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -902,7 +905,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -912,7 +915,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -921,7 +924,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                         Table "public.gtest_child2"
+                 Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -930,7 +933,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                         Table "public.gtest_child3"
+                 Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -987,7 +990,7 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                         Table "public.gtest25"
+                                 Table "generated_stored_tests.gtest25"
  Column |       Type       | Collation | Nullable |                       Default                        
 --------+------------------+-----------+----------+------------------------------------------------------
  a      | integer          |           | not null | 
@@ -1011,7 +1014,7 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                                Table "public.gtest27"
+                        Table "generated_stored_tests.gtest27"
  Column |  Type   | Collation | Nullable |                  Default                   
 --------+---------+-----------+----------+--------------------------------------------
  a      | integer |           |          | 
@@ -1037,7 +1040,7 @@ ALTER TABLE gtest27
   ALTER COLUMN b TYPE bigint,
   ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1051,7 +1054,7 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1079,7 +1082,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1101,7 +1104,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1120,7 +1123,7 @@ SELECT * FROM gtest29;
 (4 rows)
 
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1129,7 +1132,7 @@ SELECT * FROM gtest29;
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  b      | integer |           |          | 
@@ -1142,7 +1145,7 @@ CREATE TABLE gtest30 (
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 \d gtest30
-              Table "public.gtest30"
+      Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1150,7 +1153,7 @@ ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-             Table "public.gtest30_1"
+     Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1167,7 +1170,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                            Table "public.gtest30"
+                    Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1175,7 +1178,7 @@ ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                           Table "public.gtest30_1"
+                   Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1336,14 +1339,14 @@ CREATE TABLE gtest28a (
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                           Table "public.gtest28a"
+                   Table "generated_stored_tests.gtest28a"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
-                           Table "public.gtest28b"
+                   Table "generated_stored_tests.gtest28b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index cb55d77821f..c18e0e1f655 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -2,12 +2,16 @@
 SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
 
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
+
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
-- 
2.46.0

From 71bafa088c96746820876e9934658044d11826c5 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 8 Aug 2024 08:13:48 +0200
Subject: [PATCH v2 3/3] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 104 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/analyze.c                  |   8 +
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_clause.c             |   4 +
 src/backend/parser/parse_merge.c              |   1 +
 src/backend/parser/parse_relation.c           |   9 +-
 src/backend/parser/parse_utilcmd.c            |  40 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 151 +++-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   3 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/parser/parse_node.h               |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |  27 +-
 ...rated_stored.out => generated_virtual.out} | 835 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |  10 +-
 ...rated_stored.sql => generated_virtual.sql} | 301 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 55 files changed, 1280 insertions(+), 711 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (69%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (72%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60a..7e0b09e279b 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b5..186dda1e8d0 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f3eb055e2c7..926c1fddbe3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0734716ad90..058d53364db 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index b654fae1b2f..579b1d61660 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 626d35514cc..785ae6aa04f 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 6a2822adad7..10647332622 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -271,6 +271,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -283,10 +288,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f21..ee79867d969 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2e..5953d24ae8f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c590a2adc35..89d6d2025fa 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1012,6 +1012,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c5a56c75f69..ec4e8bc3902 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1f94f4fdbbc..f0049d742f3 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2940,6 +2940,12 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname)));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3211,6 +3217,12 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname)));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6044,7 +6056,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7736,6 +7748,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 const char *colName, LOCKMODE lockmode)
 {
 	HeapTuple	tuple;
+	Form_pg_attribute attTup;
 	AttrNumber	attnum;
 	Relation	attr_rel;
 	ObjectAddress address;
@@ -7752,8 +7765,8 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				(errcode(ERRCODE_UNDEFINED_COLUMN),
 				 errmsg("column \"%s\" of relation \"%s\" does not exist",
 						colName, RelationGetRelationName(rel))));
-
-	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
+	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = attTup->attnum;
 
 	/* Prevent them from altering a system attribute */
 	if (attnum <= 0)
@@ -7762,12 +7775,20 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
-	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
+	if (!attTup->attnotnull)
 	{
-		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = true;
+		attTup->attnotnull = true;
 
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
@@ -7778,7 +7799,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 		 * already found that we must verify some other not-null constraint.
 		 */
 		if (!tab->verify_new_notnull &&
-			!NotNullImpliedByRelConstraints(rel, (Form_pg_attribute) GETSTRUCT(tuple)))
+			!NotNullImpliedByRelConstraints(rel, attTup))
 		{
 			/* Tell Phase 3 it needs to test the constraint */
 			tab->verify_new_notnull = true;
@@ -8360,7 +8381,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8517,17 +8549,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -9749,6 +9794,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11713,7 +11771,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12754,8 +12812,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -17912,8 +17974,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -17995,9 +18060,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 170360edda8..021328746a1 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2502,6 +2512,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3059,6 +3071,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3489,6 +3503,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6596,3 +6611,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index ea47c4d6f9c..0ffcff3afe7 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2009,6 +2009,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 4d7c92d63c1..d82170785bf 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1748,6 +1748,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2295,7 +2296,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e901203424d..e3936a0b8ea 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,6 +568,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -994,6 +995,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1459,6 +1461,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1685,6 +1688,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1936,6 +1940,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2410,6 +2415,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2477,6 +2483,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2843,6 +2850,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index a043fd4c669..16d847fa3fe 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -641,7 +641,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -791,7 +791,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -4025,7 +4025,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -4033,6 +4033,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4079,6 +4080,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17882,6 +17889,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18538,6 +18546,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495b..48524ac3fc2 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 87df79027d7..350e9e18885 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,6 +405,7 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e37..b864749f09c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index d5c2b2ff0b0..b445387b853 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -754,10 +754,36 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
+
+				/*
+				 * TODO: Prevent virtual generated columns from having a
+				 * domain type.  We would have to enforce domain constraints
+				 * when columns underlying the generated column change.  This
+				 * could possibly be implemented, but it's not.
+				 *
+				 * XXX If column->typeName is not set, then this column
+				 * definition is probably a partition definition and will
+				 * presumably get its pre-vetted type from elsewhere.  If that
+				 * doesn't hold, maybe this check needs to be moved elsewhere.
+				 */
+				if (column->generated == ATTRIBUTE_GENERATED_VIRTUAL && column->typeName)
+				{
+					Type		ctype;
+
+					ctype = typenameType(cxt->pstate, column->typeName, NULL);
+					if (((Form_pg_type) GETSTRUCT(ctype))->typtype == TYPTYPE_DOMAIN)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("virtual generated column \"%s\" cannot have a domain type",
+										column->colname),
+								 parser_errposition(cxt->pstate,
+													column->location)));
+					ReleaseSysCache(ctype);
+				}
 				break;
 
 			case CONSTR_CHECK:
@@ -842,6 +868,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index abef4eaf68b..52dc9b5fcac 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index c223a2c50af..7662810e9e2 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -90,6 +90,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
 
 
 /*
@@ -974,7 +976,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4365,6 +4368,149 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Virtual generated columns support
+ */
+
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+
+	/* incremented for every level where it's true */
+	int			ancestor_has_virtual;
+};
+
+static Node *
+expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+		List	   *rtable;
+		struct expand_generated_context context;
+
+		/*
+		 * Make a dummy range table for a single relation.  For the benefit of
+		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
+		 * PRS2_NEW_VARNO.
+		 */
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		rtable = list_make2(rte, rte);
+		context.rtables = list_make1(rtable);
+
+		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
+	}
+	else
+		return node;
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4409,9 +4555,12 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
+		struct expand_generated_context context = {0};
 
 		query = fireRIRrules(query, NIL);
 
+		query = expand_generated_columns_in_query(query, &context);
+
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 66ed24e4012..4f756acd39d 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index b6e01d3d292..4b2aac8cd33 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15998,6 +15998,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 5bcc2244d58..c3d6022015c 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 7c9a1f234c6..4309d3e757d 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 85a62b538e5..7fabdc0cd97 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2745,6 +2747,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f7fe834cf45..96167877b75 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -492,6 +492,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9d..1b02128548b 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be345..9611aa82352 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 21b2b045933..cb715ad08b6 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index dd74a1a9f0b..be53a9f8837 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -217,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -1091,9 +1112,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 69%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index dd74a1a9f0b..3e90132edad 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +211,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +288,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +311,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +327,41 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +374,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +412,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +434,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +499,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +508,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +523,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +538,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +551,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +559,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +592,139 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+LINE 1: CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENE...
+                                                 ^
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +734,10 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +751,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +788,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +796,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +903,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +958,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +966,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1032,20 +984,19 @@ ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0;  -- error
 ERROR:  generation expression for column "x" cannot be cast automatically to type boolean
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1054,12 +1005,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1071,7 +1022,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1082,107 +1033,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1190,7 +1152,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1243,7 +1205,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1253,12 +1215,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1268,8 +1230,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1280,6 +1242,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1293,9 +1257,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1319,14 +1285,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1334,22 +1299,46 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index b0804691f5d..31e5d151051 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..46fef4aa2f4 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 72%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..574a176e399 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +142,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +173,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +234,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +249,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +260,168 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +429,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +441,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +472,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +494,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +508,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +520,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +547,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +556,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +567,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +629,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +685,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +693,16 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();
-- 
2.46.0

From bebdc5f805066037957f7e1174efde8df3dc3d64 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 8 Aug 2024 08:13:48 +0200
Subject: [PATCH v3 1/3] Rename regress test generated to generated_stored

This makes naming room to have another test file for virtual generated
columns.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 .../regress/expected/{generated.out => generated_stored.out}    | 0
 src/test/regress/parallel_schedule                              | 2 +-
 src/test/regress/sql/{generated.sql => generated_stored.sql}    | 0
 3 files changed, 1 insertion(+), 1 deletion(-)
 rename src/test/regress/expected/{generated.out => generated_stored.out} (100%)
 rename src/test/regress/sql/{generated.sql => generated_stored.sql} (100%)

diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated_stored.out
similarity index 100%
rename from src/test/regress/expected/generated.out
rename to src/test/regress/expected/generated_stored.out
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 2429ec2bbaa..b0804691f5d 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -66,7 +66,7 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated join_hash
+test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
 # ----------
 # Additional BRIN tests
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated_stored.sql
similarity index 100%
rename from src/test/regress/sql/generated.sql
rename to src/test/regress/sql/generated_stored.sql

base-commit: 4d93bbd4e0d414a33521f62d6249ac88486c866f
-- 
2.46.0

From 4cd22fc28030984a87cca2577b319dd4b1108422 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 8 Aug 2024 08:13:48 +0200
Subject: [PATCH v3 2/3] Put generated_stored test objects in a schema

This avoids naming conflicts with concurrent tests with similarly
named objects.  Currently, there are none, but a tests for virtual
generated columns are planned to be added.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 .../regress/expected/generated_stored.out     | 71 ++++++++++---------
 src/test/regress/sql/generated_stored.sql     |  8 ++-
 2 files changed, 43 insertions(+), 36 deletions(-)

diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 44058db7c1d..dd74a1a9f0b 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -4,9 +4,12 @@ SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT
 ----------+---------+--------------
 (0 rows)
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -15,14 +18,14 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                            Table "public.gtest1"
+                    Table "generated_stored_tests.gtest1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -270,7 +273,7 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                           Table "public.gtest1_1"
+                   Table "generated_stored_tests.gtest1_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -312,7 +315,7 @@ ERROR:  column "b" inherits from generated column but specifies identity
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                                Table "public.gtestx"
+                                        Table "generated_stored_tests.gtestx"
  Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
 --------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
  a      | integer |           | not null |                                     | plain   |              | 
@@ -348,7 +351,7 @@ NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                           Table "public.gtest1_y"
+                   Table "generated_stored_tests.gtest1_y"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -523,7 +526,7 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-              Table "public.gtest10"
+      Table "generated_stored_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
@@ -622,7 +625,7 @@ CREATE INDEX gtest22c_b_idx ON gtest22c (b);
 CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
 CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
 \d gtest22c
-                           Table "public.gtest22c"
+                   Table "generated_stored_tests.gtest22c"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -726,7 +729,7 @@ CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
 CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
 \d gtest23b
-                           Table "public.gtest23b"
+                   Table "generated_stored_tests.gtest23b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -805,7 +808,7 @@ DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -814,7 +817,7 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -823,7 +826,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -855,7 +858,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -865,7 +868,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -874,7 +877,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -883,7 +886,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -902,7 +905,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -912,7 +915,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -921,7 +924,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                         Table "public.gtest_child2"
+                 Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -930,7 +933,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                         Table "public.gtest_child3"
+                 Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -987,7 +990,7 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                         Table "public.gtest25"
+                                 Table "generated_stored_tests.gtest25"
  Column |       Type       | Collation | Nullable |                       Default                        
 --------+------------------+-----------+----------+------------------------------------------------------
  a      | integer          |           | not null | 
@@ -1011,7 +1014,7 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                                Table "public.gtest27"
+                        Table "generated_stored_tests.gtest27"
  Column |  Type   | Collation | Nullable |                  Default                   
 --------+---------+-----------+----------+--------------------------------------------
  a      | integer |           |          | 
@@ -1037,7 +1040,7 @@ ALTER TABLE gtest27
   ALTER COLUMN b TYPE bigint,
   ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1051,7 +1054,7 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1079,7 +1082,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1101,7 +1104,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1120,7 +1123,7 @@ SELECT * FROM gtest29;
 (4 rows)
 
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1129,7 +1132,7 @@ SELECT * FROM gtest29;
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  b      | integer |           |          | 
@@ -1142,7 +1145,7 @@ CREATE TABLE gtest30 (
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 \d gtest30
-              Table "public.gtest30"
+      Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1150,7 +1153,7 @@ ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-             Table "public.gtest30_1"
+     Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1167,7 +1170,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                            Table "public.gtest30"
+                    Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1175,7 +1178,7 @@ ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                           Table "public.gtest30_1"
+                   Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1336,14 +1339,14 @@ CREATE TABLE gtest28a (
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                           Table "public.gtest28a"
+                   Table "generated_stored_tests.gtest28a"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
-                           Table "public.gtest28b"
+                   Table "generated_stored_tests.gtest28b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index cb55d77821f..c18e0e1f655 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -2,12 +2,16 @@
 SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
 
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
+
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
-- 
2.46.0

From fcdcdb8725a97e06a1e35297a9fa96e03d922249 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 20 Aug 2024 12:17:46 +0200
Subject: [PATCH v3 3/3] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 120 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/analyze.c                  |   8 +
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_clause.c             |   4 +
 src/backend/parser/parse_merge.c              |   1 +
 src/backend/parser/parse_relation.c           |   9 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 171 +++-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   3 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/parser/parse_node.h               |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |  32 +-
 ...rated_stored.out => generated_virtual.out} | 853 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |  14 +-
 ...rated_stored.sql => generated_virtual.sql} | 319 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 58 files changed, 1350 insertions(+), 712 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (68%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (71%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60a..7e0b09e279b 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b5..186dda1e8d0 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f3eb055e2c7..926c1fddbe3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0734716ad90..058d53364db 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index b654fae1b2f..579b1d61660 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 626d35514cc..785ae6aa04f 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 6a2822adad7..10647332622 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -271,6 +271,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -283,10 +288,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f21..ee79867d969 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2e..5953d24ae8f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1c6da286d43..0c95a11f044 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2048,6 +2048,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 01b43cc6a84..29358f37307 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 902eb1a4508..f79ff40c3ec 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1030,6 +1030,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c5a56c75f69..ec4e8bc3902 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7a36db6af6d..2cfdda16d40 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2940,6 +2940,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3211,6 +3220,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6044,7 +6062,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7736,6 +7754,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 const char *colName, LOCKMODE lockmode)
 {
 	HeapTuple	tuple;
+	Form_pg_attribute attTup;
 	AttrNumber	attnum;
 	Relation	attr_rel;
 	ObjectAddress address;
@@ -7752,8 +7771,8 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				(errcode(ERRCODE_UNDEFINED_COLUMN),
 				 errmsg("column \"%s\" of relation \"%s\" does not exist",
 						colName, RelationGetRelationName(rel))));
-
-	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
+	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = attTup->attnum;
 
 	/* Prevent them from altering a system attribute */
 	if (attnum <= 0)
@@ -7762,12 +7781,20 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
-	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
+	if (!attTup->attnotnull)
 	{
-		((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = true;
+		attTup->attnotnull = true;
 
 		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
 
@@ -7778,7 +7805,7 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 		 * already found that we must verify some other not-null constraint.
 		 */
 		if (!tab->verify_new_notnull &&
-			!NotNullImpliedByRelConstraints(rel, (Form_pg_attribute) GETSTRUCT(tuple)))
+			!NotNullImpliedByRelConstraints(rel, attTup))
 		{
 			/* Tell Phase 3 it needs to test the constraint */
 			tab->verify_new_notnull = true;
@@ -8360,7 +8387,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8517,17 +8555,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8670,6 +8721,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9749,6 +9810,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11730,7 +11804,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12771,8 +12845,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -17929,8 +18007,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18012,9 +18093,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 170360edda8..021328746a1 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2502,6 +2512,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3059,6 +3071,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3489,6 +3503,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6596,3 +6611,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 77394e76c37..58b0f2f76d6 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2119,6 +2119,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 29e186fa73d..a49b1e821e0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1743,6 +1743,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2290,7 +2291,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e901203424d..e3936a0b8ea 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,6 +568,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -994,6 +995,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1459,6 +1461,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1685,6 +1688,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1936,6 +1940,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2410,6 +2415,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2477,6 +2483,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2843,6 +2850,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index c3f25582c38..6f794fc61eb 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -641,7 +641,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -791,7 +791,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -4025,7 +4025,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -4033,6 +4033,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4079,6 +4080,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17863,6 +17870,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18518,6 +18526,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495b..48524ac3fc2 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 87df79027d7..350e9e18885 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,6 +405,7 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e37..b864749f09c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index d5c2b2ff0b0..cfc86d3f6cf 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -754,7 +754,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -842,6 +842,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index abef4eaf68b..52dc9b5fcac 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index c223a2c50af..03b4b857ed1 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -44,6 +44,7 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 
 
 /* We use a list of these to detect recursion in RewriteQuery */
@@ -90,6 +91,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
 
 
 /*
@@ -974,7 +977,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4365,6 +4369,168 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Virtual generated columns support
+ */
+
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+
+	/* incremented for every level where it's true */
+	int			ancestor_has_virtual;
+};
+
+static Node *
+expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			Oid			attcollid;
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+
+			/*
+			 * If the column definition has a collation and it is different
+			 * from the collation of the generation expression, put a COLLATE
+			 * clause around the expression.
+			 */
+			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+			if (attcollid && attcollid != exprCollation(node))
+			{
+				CollateExpr *ce = makeNode(CollateExpr);
+
+				ce->arg = (Expr *) node;
+				ce->collOid = attcollid;
+				ce->location = -1;
+
+				node = (Node *) ce;
+			}
+
+			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+		List	   *rtable;
+		struct expand_generated_context context;
+
+		/*
+		 * Make a dummy range table for a single relation.  For the benefit of
+		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
+		 * PRS2_NEW_VARNO.
+		 */
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		rtable = list_make2(rte, rte);
+		context.rtables = list_make1(rtable);
+
+		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
+	}
+	else
+		return node;
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4409,9 +4575,12 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
+		struct expand_generated_context context = {0};
 
 		query = fireRIRrules(query, NIL);
 
+		query = expand_generated_columns_in_query(query, &context);
+
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 66ed24e4012..4f756acd39d 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index b6e01d3d292..4b2aac8cd33 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15998,6 +15998,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 5bcc2244d58..c3d6022015c 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 7c9a1f234c6..4309d3e757d 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index c512824cd1c..235ad73eedc 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 85a62b538e5..7fabdc0cd97 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2745,6 +2747,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index bb191b1f469..0597d9ea9e1 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -491,6 +491,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9d..1b02128548b 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be345..9611aa82352 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 21b2b045933..cb715ad08b6 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index dd74a1a9f0b..2e8e4c71d18 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -217,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -762,6 +783,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -1091,9 +1117,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 68%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index dd74a1a9f0b..d28dba4f51f 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +211,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +288,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +311,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +327,42 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +375,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +413,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +435,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +500,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +509,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +524,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +539,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +552,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +560,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +593,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +738,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +756,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +793,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +801,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +908,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +963,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +971,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1032,20 +989,19 @@ ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0;  -- error
 ERROR:  generation expression for column "x" cannot be cast automatically to type boolean
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1054,12 +1010,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1071,7 +1027,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1082,107 +1038,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1190,7 +1157,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1243,7 +1210,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1253,12 +1220,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1268,8 +1235,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1280,6 +1247,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1293,9 +1262,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1319,14 +1290,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1334,22 +1304,59 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index b0804691f5d..31e5d151051 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..36a6c2bddbe 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -390,6 +398,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 71%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..2bb9e1b45fe 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +142,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +173,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +234,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +249,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +260,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +433,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +445,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +476,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +498,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +512,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +524,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +551,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +560,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +633,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +689,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +697,30 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
+
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();
-- 
2.46.0

From 0169f9e1cb3f83d75f1697f47825977a36afa63e Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 29 Aug 2024 16:37:27 +0800
Subject: [PATCH v4 1/1] misc

---
 contrib/pageinspect/expected/page.out         |   35 +
 contrib/pageinspect/sql/page.sql              |   17 +
 .../postgres_fdw/expected/postgres_fdw.out    |   81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |    9 +-
 doc/src/sgml/catalogs.sgml                    |    4 +-
 doc/src/sgml/ddl.sgml                         |   25 +-
 doc/src/sgml/ref/alter_table.sgml             |   14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |   11 +-
 doc/src/sgml/ref/create_table.sgml            |   22 +-
 doc/src/sgml/ref/create_trigger.sgml          |    2 +-
 doc/src/sgml/trigger.sgml                     |    4 +
 src/backend/access/common/tupdesc.c           |    3 +
 src/backend/access/heap/heapam_handler.c      |    2 +
 src/backend/catalog/heap.c                    |   13 +-
 src/backend/commands/analyze.c                |    4 +
 src/backend/commands/functioncmds.c           |   35 +-
 src/backend/commands/indexcmds.c              |   29 +-
 src/backend/commands/statscmds.c              |   20 +-
 src/backend/commands/tablecmds.c              |  118 +-
 src/backend/commands/trigger.c                |   48 +-
 src/backend/commands/view.c                   |    3 +
 src/backend/executor/execExprInterp.c         |    4 +
 src/backend/executor/execMain.c               |   16 +-
 src/backend/parser/analyze.c                  |    8 +
 src/backend/parser/gram.y                     |   15 +-
 src/backend/parser/parse_clause.c             |    4 +
 src/backend/parser/parse_merge.c              |    1 +
 src/backend/parser/parse_relation.c           |    9 +-
 src/backend/parser/parse_utilcmd.c            |   14 +-
 src/backend/replication/pgoutput/pgoutput.c   |    3 +-
 src/backend/rewrite/rewriteHandler.c          |  316 +++-
 src/backend/utils/adt/varlena.c               |   18 +-
 src/backend/utils/cache/partcache.c           |    3 +
 src/backend/utils/cache/relcache.c            |    2 +
 src/bin/pg_dump/pg_dump.c                     |    3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |    6 +-
 src/bin/psql/describe.c                       |    6 +
 src/include/access/tupdesc.h                  |    1 +
 src/include/catalog/heap.h                    |    1 +
 src/include/catalog/pg_attribute.h            |    1 +
 src/include/catalog/pg_extension.h            |    3 -
 src/include/nodes/parsenodes.h                |    3 +
 src/include/parser/kwlist.h                   |    1 +
 src/include/parser/parse_node.h               |    1 +
 src/include/rewrite/rewriteHandler.h          |    2 +
 src/pl/plperl/expected/plperl_trigger.out     |    7 +-
 src/pl/plperl/plperl.c                        |    3 +
 src/pl/plperl/sql/plperl_trigger.sql          |    3 +-
 src/pl/plpython/expected/plpython_trigger.out |    7 +-
 src/pl/plpython/plpy_typeio.c                 |    3 +
 src/pl/plpython/sql/plpython_trigger.sql      |    3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |   19 +-
 src/pl/tcl/pltcl.c                            |    3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |    3 +-
 .../regress/expected/create_table_like.out    |   23 +-
 .../{generated.out => generated_stored.out}   |  103 +-
 .../regress/expected/generated_virtual.out    | 1363 +++++++++++++++++
 src/test/regress/parallel_schedule            |    5 +-
 src/test/regress/sql/create_table_like.sql    |    2 +-
 .../{generated.sql => generated_stored.sql}   |   22 +-
 src/test/regress/sql/generated_virtual.sql    |  726 +++++++++
 src/test/subscription/t/011_generated.pl      |   38 +-
 62 files changed, 3052 insertions(+), 221 deletions(-)
 rename src/test/regress/expected/{generated.out => generated_stored.out} (94%)
 create mode 100644 src/test/regress/expected/generated_virtual.out
 rename src/test/regress/sql/{generated.sql => generated_stored.sql} (96%)
 create mode 100644 src/test/regress/sql/generated_virtual.sql

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60..7e0b09e279 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b..186dda1e8d 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f3eb055e2c..926c1fddbe 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0734716ad9..058d53364d 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index b654fae1b2..579b1d6166 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index b671858627..378ae934ba 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ INSERT INTO people (id, name, address) VALUE (<emphasis>DEFAULT</emphasis>, 'C',
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ INSERT INTO people (id, name, address) VALUE (<emphasis>DEFAULT</emphasis>, 'C',
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ CREATE TABLE people (
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 1a49f321cf..c5aaf76544 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -264,6 +264,11 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -276,10 +281,15 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b907599..21b5d6a14d 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="parameter">table_name
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f2..ee79867d96 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXI
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ CREATE TABLE cities_partdef
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee..752fe50860 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2..5953d24ae8 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef22..13840ba533 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1c6da286d4..0c95a11f04 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2048,6 +2048,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 01b43cc6a8..29358f3730 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 902eb1a450..f79ff40c3e 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1030,6 +1030,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index d43b89d3ef..6593fd7d81 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -1689,18 +1689,13 @@ CreateCast(CreateCastStmt *stmt)
 					 errmsg("source and target data types are not physically compatible")));
 
 		/*
-		 * We know that composite, array, range and enum types are never
-		 * binary-compatible with each other.  They all have OIDs embedded in
-		 * them.
+		 * We know that composite, enum and array types are never binary-
+		 * compatible with each other.  They all have OIDs embedded in them.
 		 *
 		 * Theoretically you could build a user-defined base type that is
-		 * binary-compatible with such a type.  But we disallow it anyway, as
-		 * in practice such a cast is surely a mistake.  You can always work
-		 * around that by writing a cast function.
-		 *
-		 * NOTE: if we ever have a kind of container type that doesn't need to
-		 * be rejected for this reason, we'd likely need to recursively apply
-		 * all of these same checks to the contained type(s).
+		 * binary-compatible with a composite, enum, or array type.  But we
+		 * disallow that too, as in practice such a cast is surely a mistake.
+		 * You can always work around that by writing a cast function.
 		 */
 		if (sourcetyptype == TYPTYPE_COMPOSITE ||
 			targettyptype == TYPTYPE_COMPOSITE)
@@ -1708,26 +1703,18 @@ CreateCast(CreateCastStmt *stmt)
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 					 errmsg("composite data types are not binary-compatible")));
 
-		if (OidIsValid(get_element_type(sourcetypeid)) ||
-			OidIsValid(get_element_type(targettypeid)))
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-					 errmsg("array data types are not binary-compatible")));
-
-		if (sourcetyptype == TYPTYPE_RANGE ||
-			targettyptype == TYPTYPE_RANGE ||
-			sourcetyptype == TYPTYPE_MULTIRANGE ||
-			targettyptype == TYPTYPE_MULTIRANGE)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-					 errmsg("range data types are not binary-compatible")));
-
 		if (sourcetyptype == TYPTYPE_ENUM ||
 			targettyptype == TYPTYPE_ENUM)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 					 errmsg("enum data types are not binary-compatible")));
 
+		if (OidIsValid(get_element_type(sourcetypeid)) ||
+			OidIsValid(get_element_type(targettypeid)))
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+					 errmsg("array data types are not binary-compatible")));
+
 		/*
 		 * We also disallow creating binary-compatibility casts involving
 		 * domains.  Casting from a domain to its base type is already
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c5a56c75f6..ec4e8bc390 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d2..744b3508c2 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 70cd266916..4227a955ca 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2936,6 +2936,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3207,6 +3216,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -5986,7 +6004,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7703,6 +7721,13 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
 	 * Okay, actually perform the catalog change ... if needed
@@ -8301,7 +8326,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8458,17 +8494,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8611,6 +8660,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9690,6 +9749,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11671,7 +11743,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12677,6 +12749,16 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Cannot specify USING when altering type of a generated column, because
+	 * that would violate the generation expression.
+	 */
+	if (attTup->attgenerated && def->cooked_default)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+				 errmsg("cannot specify USING when altering type of generated column"),
+				 errdetail("Column \"%s\" is a generated column.", colName)));
+
 	/*
 	 * Cannot specify USING when altering type of a generated column, because
 	 * that would violate the generation expression.
@@ -12722,8 +12804,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -17884,8 +17970,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -17967,9 +18056,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 170360edda..021328746a 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2502,6 +2512,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3059,6 +3071,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3489,6 +3503,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6596,3 +6611,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/commands/view.c b/src/backend/commands/view.c
index fdad833832..150115c13b 100644
--- a/src/backend/commands/view.c
+++ b/src/backend/commands/view.c
@@ -278,6 +278,9 @@ checkViewColumns(TupleDesc newdesc, TupleDesc olddesc)
 		Form_pg_attribute newattr = TupleDescAttr(newdesc, i);
 		Form_pg_attribute oldattr = TupleDescAttr(olddesc, i);
 
+		Assert(newattr->attgenerated == '\0');
+		Assert(oldattr->attgenerated == '\0');
+
 		/* XXX msg not right, but we don't support DROP COL on view anyway */
 		if (newattr->attisdropped != oldattr->attisdropped)
 			ereport(ERROR,
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 77394e76c3..58b0f2f76d 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2119,6 +2119,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 29e186fa73..898f99a48c 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -255,6 +255,17 @@ standard_ExecutorStart(QueryDesc *queryDesc, int eflags)
 	 */
 	InitPlan(queryDesc, eflags);
 
+	{
+		int i;
+		for (i = 0; i < queryDesc->tupDesc->natts; i++)
+		{
+			Form_pg_attribute att = TupleDescAttr(queryDesc->tupDesc, i);
+			if (att->attisdropped)
+				continue;
+			Assert(att->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL);
+			Assert(att->attgenerated != ATTRIBUTE_GENERATED_STORED);
+		}
+	}
 	MemoryContextSwitchTo(oldcontext);
 }
 
@@ -1743,6 +1754,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2290,7 +2302,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e901203424..e3936a0b8e 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,6 +568,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -994,6 +995,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1459,6 +1461,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1685,6 +1688,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1936,6 +1940,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2410,6 +2415,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2477,6 +2483,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2843,6 +2850,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 84cef57a70..18ce875c40 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -640,7 +640,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -788,7 +788,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3973,7 +3973,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3981,6 +3981,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4027,6 +4028,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17809,6 +17816,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18462,6 +18470,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495..48524ac3fc 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 87df79027d..350e9e1888 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,6 +405,7 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e3..b864749f09 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 79cad4ab30..03301f9c53 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -751,7 +751,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -839,6 +839,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index abef4eaf68..52dc9b5fca 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index c223a2c50a..598ca75fcc 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -30,6 +30,7 @@
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
+#include "nodes/print.h"
 #include "optimizer/optimizer.h"
 #include "parser/analyze.h"
 #include "parser/parse_coerce.h"
@@ -44,6 +45,7 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 
 
 /* We use a list of these to detect recursion in RewriteQuery */
@@ -90,8 +92,20 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
 
-
+typedef struct virtual_generated_context
+{
+	int			ancestor_has_virtual;
+	List		*rtables;
+	List		*virtual_gen_tlist;
+	List		*virtual_gen_varno;
+	List		*virtual_gen_rte;
+}	virtual_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
+static Node *
+get_generated_columns_tlelist_mutator(Node *node, virtual_generated_context *context);
+static Query *make_generated_columns_targetlist_query(Query *query, virtual_generated_context *context);
 /*
  * AcquireRewriteLocks -
  *	  Acquire suitable locks on all the relations mentioned in the Query.
@@ -974,7 +988,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4365,6 +4380,284 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Virtual generated columns support
+ */
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+
+	/* incremented for every level where it's true */
+	int			ancestor_has_virtual;
+};
+
+static Node *
+expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			Oid			attcollid;
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+
+			/*
+			 * If the column definition has a collation and it is different
+			 * from the collation of the generation expression, put a COLLATE
+			 * clause around the expression.
+			 */
+			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+			if (attcollid && attcollid != exprCollation(node))
+			{
+				CollateExpr *ce = makeNode(CollateExpr);
+
+				ce->arg = (Expr *) node;
+				ce->collOid = attcollid;
+				ce->location = -1;
+
+				node = (Node *) ce;
+			}
+
+			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+pg_attribute_unused()
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+		List	   *rtable;
+		struct expand_generated_context context;
+
+		/*
+		 * Make a dummy range table for a single relation.  For the benefit of
+		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
+		 * PRS2_NEW_VARNO.
+		 */
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		rtable = list_make2(rte, rte);
+		context.rtables = list_make1(rtable);
+
+		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
+	}
+	else
+		return node;
+}
+
+static Query *
+make_generated_columns_targetlist_query(Query *query, virtual_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	if (context->ancestor_has_virtual)
+		query =  query_tree_mutator(query,
+									get_generated_columns_tlelist_mutator,
+									context,
+									QTW_DONT_COPY_QUERY);
+	else
+	{
+		foreach_node(RangeTblEntry, rte, query->rtable)
+		{
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = make_generated_columns_targetlist_query(rte->subquery, context);
+		}
+
+		foreach_node(CommonTableExpr, cte, query->cteList)
+			cte->ctequery = (Node *) make_generated_columns_targetlist_query(castNode(Query, cte->ctequery), context);
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+	return query;
+}
+
+static Node *
+get_generated_columns_tlelist_mutator(Node *node, virtual_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		Relation	rt_entry_relation;
+		RangeTblEntry *rte;
+		TupleDesc	tupdesc;
+		AttrNumber	attnum;
+		int			i;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+		if (IS_SPECIAL_VARNO(v->varno))
+			return node;
+		rte = rt_fetch(v->varno, rtable);
+		if (rte->rtekind != RTE_RELATION)
+			return node;
+
+		relid = rte->relid;
+		Assert(OidIsValid(relid));
+
+		attnum = v->varattno;
+		rt_entry_relation = table_open(relid, NoLock);
+		tupdesc = RelationGetDescr(rt_entry_relation);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			Oid			attcollid;
+			Node		*virtual_expr;
+			TargetEntry *tle;
+			for (i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+				if (att->attisdropped)
+					continue;
+
+				if (att->attgenerated == 'v' && attnum == att->attnum)
+				{
+					virtual_expr = build_column_default(rt_entry_relation, attnum);
+					attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+					if (attcollid && attcollid != exprCollation(virtual_expr))
+					{
+						CollateExpr *ce = makeNode(CollateExpr);
+
+						ce->arg = (Expr *) virtual_expr;
+						ce->collOid = attcollid;
+						ce->location = -1;
+
+						virtual_expr = (Node *) ce;
+					}
+					ChangeVarNodes(virtual_expr, 1, v->varno, v->varlevelsup);
+					context->virtual_gen_varno = list_append_unique_int(context->virtual_gen_varno, v->varno);
+					context->virtual_gen_rte = list_append_unique_ptr(context->virtual_gen_rte, rte);
+
+					tle = makeTargetEntry((Expr *) virtual_expr, att->attnum,
+										NULL,
+										false);
+					tle->resorigtbl = relid;
+					tle->resorigcol = attnum;
+					context->virtual_gen_tlist = lappend(context->virtual_gen_tlist, tle);
+				}
+			}
+		}
+		table_close(rt_entry_relation, NoLock);
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *newnode = (Query *) node;
+		context->rtables = lappend(context->rtables, newnode->rtable);
+		newnode = query_tree_mutator((Query *) node,
+									get_generated_columns_tlelist_mutator,
+									(void *) context,
+									0);
+		return (Node *) newnode;
+	}
+	else
+		return expression_tree_mutator(node, get_generated_columns_tlelist_mutator, (void *) context);
+}
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4409,9 +4702,26 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
-
+		virtual_generated_context gen_context = {0};
+		ListCell   *lc,
+					*lc2;
 		query = fireRIRrules(query, NIL);
+		query = make_generated_columns_targetlist_query(query, &gen_context);
 
+		forboth(lc, gen_context.virtual_gen_varno, lc2, gen_context.virtual_gen_rte)
+		{
+			int			result_varno = lfirst_int(lc);
+			RangeTblEntry *virtual_rte = lfirst_node(RangeTblEntry, lc2);
+			query = (Query *)
+				ReplaceVarsFromTargetList((Node *)query,
+											result_varno,
+											0,
+											virtual_rte,
+											gen_context.virtual_gen_tlist,
+											REPLACEVARS_CHANGE_VARNO,
+											result_varno,
+											&query->hasSubLinks);
+		}
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 7c6391a276..f2ecef000a 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1521,12 +1521,12 @@ check_collation_set(Oid collid)
 	}
 }
 
-/*
- * varstr_cmp()
- *
- * Comparison function for text strings with given lengths, using the
- * appropriate locale. Returns an integer less than, equal to, or greater than
- * zero, indicating whether arg1 is less than, equal to, or greater than arg2.
+/* varstr_cmp()
+ * Comparison function for text strings with given lengths.
+ * Includes locale support, but must copy strings to temporary memory
+ *	to allow null-termination for inputs to strcoll().
+ * Returns an integer less than, equal to, or greater than zero, indicating
+ * whether arg1 is less than, equal to, or greater than arg2.
  *
  * Note: many functions that depend on this are marked leakproof; therefore,
  * avoid reporting the actual contents of the input when throwing errors.
@@ -1541,6 +1541,12 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
 
 	check_collation_set(collid);
 
+	/*
+	 * Unfortunately, there is no strncoll(), so in the non-C locale case we
+	 * have to do some memory copying.  This turns out to be significantly
+	 * slower, so we optimize the case where LC_COLLATE is C.  We also try to
+	 * optimize relatively-short strings by avoiding palloc/pfree overhead.
+	 */
 	if (lc_collate_is_c(collid))
 	{
 		result = memcmp(arg1, arg2, Min(len1, len2));
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc..1dee7c1e89 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 66ed24e401..4f756acd39 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index b6e01d3d29..4b2aac8cd3 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15998,6 +15998,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 5bcc2244d5..c3d6022015 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@ my %tests = (
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 7c9a1f234c..4309d3e757 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d66..6ef4024958 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index c512824cd1..235ad73eed 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb..8f158dc608 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/catalog/pg_extension.h b/src/include/catalog/pg_extension.h
index 673181b39a..cdfacc0930 100644
--- a/src/include/catalog/pg_extension.h
+++ b/src/include/catalog/pg_extension.h
@@ -56,7 +56,4 @@ DECLARE_TOAST(pg_extension, 4147, 4148);
 DECLARE_UNIQUE_INDEX_PKEY(pg_extension_oid_index, 3080, ExtensionOidIndexId, pg_extension, btree(oid oid_ops));
 DECLARE_UNIQUE_INDEX(pg_extension_name_index, 3081, ExtensionNameIndexId, pg_extension, btree(extname name_ops));
 
-MAKE_SYSCACHE(EXTENSIONOID, pg_extension_oid_index, 2);
-MAKE_SYSCACHE(EXTENSIONNAME, pg_extension_name_index, 2);
-
 #endif							/* PG_EXTENSION_H */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 124d853e49..355f52199f 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2730,6 +2732,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f8659078ce..6416f9b110 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -489,6 +489,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9..1b02128548 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71c..a646a20675 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03..42c52ecbba 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be34..9611aa8235 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80a..2798a02fa1 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb520..64eab2fa3f 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8da..51e1d61025 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a..440549c078 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba6..5298e50a5e 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 21b2b04593..cb715ad08b 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83b..0ed00f4952 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ ALTER TABLE trigger_test DROP dropme;
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040f..97157dc635 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated.out b/src/test/regress/expected/generated_stored.out
similarity index 94%
rename from src/test/regress/expected/generated.out
rename to src/test/regress/expected/generated_stored.out
index 499072e14c..8f0951e26a 100644
--- a/src/test/regress/expected/generated.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,12 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -15,14 +18,14 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                            Table "public.gtest1"
+                    Table "generated_stored_tests.gtest1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -214,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -270,7 +294,7 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                           Table "public.gtest1_1"
+                   Table "generated_stored_tests.gtest1_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -312,7 +336,7 @@ ERROR:  column "b" inherits from generated column but specifies identity
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                                Table "public.gtestx"
+                                        Table "generated_stored_tests.gtestx"
  Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
 --------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
  a      | integer |           | not null |                                     | plain   |              | 
@@ -348,7 +372,7 @@ NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                           Table "public.gtest1_y"
+                   Table "generated_stored_tests.gtest1_y"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -523,7 +547,7 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-              Table "public.gtest10"
+      Table "generated_stored_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
@@ -622,7 +646,7 @@ CREATE INDEX gtest22c_b_idx ON gtest22c (b);
 CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
 CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
 \d gtest22c
-                           Table "public.gtest22c"
+                   Table "generated_stored_tests.gtest22c"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -726,7 +750,7 @@ CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
 CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
 \d gtest23b
-                           Table "public.gtest23b"
+                   Table "generated_stored_tests.gtest23b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           | not null | 
@@ -759,6 +783,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -805,7 +834,7 @@ DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -814,7 +843,7 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -823,7 +852,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -855,7 +884,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -865,7 +894,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -874,7 +903,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                          Table "public.gtest_child2"
+                  Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -883,7 +912,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                          Table "public.gtest_child3"
+                  Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default                
 --------+--------+-----------+----------+--------------------------------------
  f1     | date   |           | not null | 
@@ -902,7 +931,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-                   Partitioned table "public.gtest_parent"
+           Partitioned table "generated_stored_tests.gtest_parent"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -912,7 +941,7 @@ Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                          Table "public.gtest_child"
+                  Table "generated_stored_tests.gtest_child"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -921,7 +950,7 @@ Number of partitions: 3 (Use \d+ to list them.)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                         Table "public.gtest_child2"
+                 Table "generated_stored_tests.gtest_child2"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -930,7 +959,7 @@ Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                         Table "public.gtest_child3"
+                 Table "generated_stored_tests.gtest_child3"
  Column |  Type  | Collation | Nullable |               Default               
 --------+--------+-----------+----------+-------------------------------------
  f1     | date   |           | not null | 
@@ -987,7 +1016,7 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                         Table "public.gtest25"
+                                 Table "generated_stored_tests.gtest25"
  Column |       Type       | Collation | Nullable |                       Default                        
 --------+------------------+-----------+----------+------------------------------------------------------
  a      | integer          |           | not null | 
@@ -1011,7 +1040,7 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                                Table "public.gtest27"
+                        Table "generated_stored_tests.gtest27"
  Column |  Type   | Collation | Nullable |                  Default                   
 --------+---------+-----------+----------+--------------------------------------------
  a      | integer |           |          | 
@@ -1038,7 +1067,7 @@ ALTER TABLE gtest27
   ALTER COLUMN b TYPE bigint,
   ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1052,7 +1081,7 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                              Table "public.gtest27"
+                      Table "generated_stored_tests.gtest27"
  Column |  Type  | Collation | Nullable |                 Default                  
 --------+--------+-----------+----------+------------------------------------------
  a      | bigint |           |          | 
@@ -1080,7 +1109,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1089,9 +1118,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1102,7 +1131,7 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                            Table "public.gtest29"
+                    Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1121,7 +1150,7 @@ SELECT * FROM gtest29;
 (4 rows)
 
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1130,7 +1159,7 @@ SELECT * FROM gtest29;
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
 \d gtest29
-              Table "public.gtest29"
+      Table "generated_stored_tests.gtest29"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  b      | integer |           |          | 
@@ -1143,7 +1172,7 @@ CREATE TABLE gtest30 (
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 \d gtest30
-              Table "public.gtest30"
+      Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1151,7 +1180,7 @@ ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-             Table "public.gtest30_1"
+     Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
@@ -1168,7 +1197,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                            Table "public.gtest30"
+                    Table "generated_stored_tests.gtest30"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1176,7 +1205,7 @@ ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                           Table "public.gtest30_1"
+                   Table "generated_stored_tests.gtest30_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
@@ -1337,14 +1366,14 @@ CREATE TABLE gtest28a (
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                           Table "public.gtest28a"
+                   Table "generated_stored_tests.gtest28a"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
-                           Table "public.gtest28b"
+                   Table "generated_stored_tests.gtest28b"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  b      | integer |           |          | 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
new file mode 100644
index 0000000000..597ac4d941
--- /dev/null
+++ b/src/test/regress/expected/generated_virtual.out
@@ -0,0 +1,1363 @@
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+ attrelid | attname | attgenerated 
+----------+---------+--------------
+(0 rows)
+
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
+ table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
+------------+-------------+----------------+-------------+--------------+-----------------------
+ gtest0     | a           |                | NO          | NEVER        | 
+ gtest0     | b           |                | YES         | ALWAYS       | 55
+ gtest1     | a           |                | NO          | NEVER        | 
+ gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
+(4 rows)
+
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
+ table_name | column_name | dependent_column 
+------------+-------------+------------------
+ gtest1     | a           | b
+(1 row)
+
+\d gtest1
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           | not null | 
+ b      | integer |           |          | generated always as (a * 2)
+Indexes:
+    "gtest1_pkey" PRIMARY KEY, btree (a)
+
+-- duplicate generated
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
+ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
+                                                             ^
+-- references to other generated columns, including self-references
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+ERROR:  cannot use generated column "b" in column generation expression
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
+                                                             ^
+DETAIL:  A generated column cannot reference another generated column.
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
+ERROR:  cannot use generated column "b" in column generation expression
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
+                                                             ^
+DETAIL:  A generated column cannot reference another generated column.
+-- a whole-row var is a self-reference on steroids, so disallow that too
+CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
+ERROR:  cannot use whole-row variable in column generation expression
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
+                                                 ^
+DETAIL:  This would cause the generated column to depend on its own value.
+-- invalid reference
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
+ERROR:  column "c" does not exist
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
+                                                             ^
+-- generation expression must be immutable
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
+ERROR:  generation expression is not immutable
+-- ... but be sure that the immutability test is accurate
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
+DROP TABLE gtest2;
+-- cannot have default/identity and generated
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
+LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
+                                                             ^
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
+LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
+                                                             ^
+-- reference to system column not allowed in generated column
+-- (except tableoid, which we test below)
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
+ERROR:  cannot use system column "xmin" in column generation expression
+LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
+                                                             ^
+-- various prohibited constructs
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+ERROR:  aggregate functions are not allowed in column generation expressions
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
+                                                             ^
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+ERROR:  window functions are not allowed in column generation expressions
+LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
+                                                             ^
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+ERROR:  cannot use subquery in column generation expression
+LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
+                                                             ^
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
+ERROR:  set-returning functions are not allowed in column generation expressions
+LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
+                                                             ^
+-- GENERATED BY DEFAULT not allowed
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
+ERROR:  for a generated column, GENERATED ALWAYS must be specified
+LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
+                                                             ^
+INSERT INTO gtest1 VALUES (1);
+INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
+INSERT INTO gtest1 VALUES (3, 33);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1 VALUES (3, 33), (4, 44);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1 VALUES (3, DEFAULT), (4, 44);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1 VALUES (3, 33), (4, DEFAULT);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
+DELETE FROM gtest1 WHERE a >= 3;
+UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
+UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
+ERROR:  column "b" can only be updated to DEFAULT
+DETAIL:  Column "b" is a generated column.
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
+ a | b | b2 
+---+---+----
+ 1 | 2 |  4
+ 2 | 4 |  8
+(2 rows)
+
+SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
+ a | b 
+---+---
+ 2 | 4
+(1 row)
+
+-- test that overflow error happens on read
+INSERT INTO gtest1 VALUES (2000000000);
+SELECT * FROM gtest1;
+ERROR:  integer out of range
+DELETE FROM gtest1 WHERE a = 2000000000;
+-- test with joins
+CREATE TABLE gtestx (x int, y int);
+INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
+SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+ x  | y | a | b 
+----+---+---+---
+ 11 | 1 | 1 | 2
+ 22 | 2 | 2 | 4
+(2 rows)
+
+DROP TABLE gtestx;
+-- test UPDATE/DELETE quals
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+(2 rows)
+
+UPDATE gtest1 SET a = 3 WHERE b = 4;
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+ 3 | 6
+(2 rows)
+
+DELETE FROM gtest1 WHERE b = 2;
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 3 | 6
+(1 row)
+
+-- test MERGE
+CREATE TABLE gtestm (
+  id int PRIMARY KEY,
+  f1 int,
+  f2 int,
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
+);
+INSERT INTO gtestm VALUES (1, 5, 100);
+MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
+  WHEN MATCHED THEN UPDATE SET f1 = v.f1
+  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200);
+SELECT * FROM gtestm ORDER BY id;
+ id | f1 | f2  | f3 | f4  
+----+----+-----+----+-----
+  1 | 10 | 100 | 20 | 200
+  2 | 20 | 200 | 40 | 400
+(2 rows)
+
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
+DROP TABLE gtestm;
+-- views
+CREATE VIEW gtest1v AS SELECT * FROM gtest1;
+SELECT * FROM gtest1v;
+ a | b 
+---+---
+ 3 | 6
+(1 row)
+
+INSERT INTO gtest1v VALUES (4, 8);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1v VALUES (5, DEFAULT);  -- ok
+INSERT INTO gtest1v VALUES (6, 66), (7, 77);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1v VALUES (6, DEFAULT), (7, 77);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1v VALUES (6, 66), (7, DEFAULT);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1v VALUES (6, DEFAULT), (7, DEFAULT);  -- ok
+ALTER VIEW gtest1v ALTER COLUMN b SET DEFAULT 100;
+INSERT INTO gtest1v VALUES (8, DEFAULT);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+INSERT INTO gtest1v VALUES (8, DEFAULT), (9, DEFAULT);  -- error
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+SELECT * FROM gtest1v;
+ a | b  
+---+----
+ 3 |  6
+ 5 | 10
+ 6 | 12
+ 7 | 14
+(4 rows)
+
+DELETE FROM gtest1v WHERE a >= 5;
+DROP VIEW gtest1v;
+-- CTEs
+WITH foo AS (SELECT * FROM gtest1) SELECT * FROM foo;
+ a | b 
+---+---
+ 3 | 6
+(1 row)
+
+-- inheritance
+CREATE TABLE gtest1_1 () INHERITS (gtest1);
+SELECT * FROM gtest1_1;
+ a | b 
+---+---
+(0 rows)
+
+\d gtest1_1
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           | not null | 
+ b      | integer |           |          | generated always as (a * 2)
+Inherits: gtest1
+
+INSERT INTO gtest1_1 VALUES (4);
+SELECT * FROM gtest1_1;
+ a | b 
+---+---
+ 4 | 8
+(1 row)
+
+SELECT * FROM gtest1;
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
+(2 rows)
+
+-- can't have generated column that is a child of normal column
+CREATE TABLE gtest_normal (a int, b int);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
+ERROR:  child column "b" specifies generation expression
+HINT:  A child table column cannot be generated unless its parent column is.
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
+ERROR:  column "b" in child table must not be a generated column
+DROP TABLE gtest_normal, gtest_normal_child;
+-- test inheritance mismatches between parent and child
+CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column but specifies default
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
+NOTICE:  merging column "b" with inherited definition
+\d+ gtestx
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
+Inherits: gtest1
+
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
+CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
+ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
+ERROR:  column "b" in child table must be a generated column
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
+ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
+-- test multiple inheritance mismatches
+CREATE TABLE gtesty (x int, b int DEFAULT 55);
+CREATE TABLE gtest1_y () INHERITS (gtest0, gtesty);  -- error
+NOTICE:  merging multiple inherited definitions of column "b"
+ERROR:  inherited column "b" has a generation conflict
+DROP TABLE gtesty;
+CREATE TABLE gtesty (x int, b int);
+CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
+NOTICE:  merging multiple inherited definitions of column "b"
+ERROR:  inherited column "b" has a generation conflict
+DROP TABLE gtesty;
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
+CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
+NOTICE:  merging multiple inherited definitions of column "b"
+ERROR:  column "b" inherits conflicting generation expressions
+HINT:  To resolve the conflict, specify a generation expression explicitly.
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
+NOTICE:  merging multiple inherited definitions of column "b"
+NOTICE:  moving and merging column "b" with inherited definition
+DETAIL:  User-specified column moved to the position of the inherited column.
+\d gtest1_y
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           | not null | 
+ b      | integer |           |          | generated always as (x + 1)
+ x      | integer |           |          | 
+Inherits: gtest1,
+          gtesty
+
+-- test correct handling of GENERATED column that's only in child
+CREATE TABLE gtestp (f1 int);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
+INSERT INTO gtestc values(42);
+TABLE gtestc;
+ f1 | f2 
+----+----
+ 42 | 43
+(1 row)
+
+UPDATE gtestp SET f1 = f1 * 10;
+TABLE gtestc;
+ f1  | f2  
+-----+-----
+ 420 | 421
+(1 row)
+
+DROP TABLE gtestp CASCADE;
+NOTICE:  drop cascades to table gtestc
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
+INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
+SELECT * FROM gtest3 ORDER BY a;
+ a | b 
+---+---
+ 1 | 3
+ 2 | 6
+ 3 | 9
+   |  
+(4 rows)
+
+UPDATE gtest3 SET a = 22 WHERE a = 2;
+SELECT * FROM gtest3 ORDER BY a;
+ a  | b  
+----+----
+  1 |  3
+  3 |  9
+ 22 | 66
+    |   
+(4 rows)
+
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
+INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
+SELECT * FROM gtest3a ORDER BY a;
+ a |  b  
+---+-----
+ a | a+a
+ b | b+b
+ c | c+c
+   | 
+(4 rows)
+
+UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
+SELECT * FROM gtest3a ORDER BY a;
+ a  |   b   
+----+-------
+ a  | a+a
+ bb | bb+bb
+ c  | c+c
+    | 
+(4 rows)
+
+-- COPY
+TRUNCATE gtest1;
+INSERT INTO gtest1 (a) VALUES (1), (2);
+COPY gtest1 TO stdout;
+1
+2
+COPY gtest1 (a, b) TO stdout;
+ERROR:  column "b" is a generated column
+DETAIL:  Generated columns cannot be used in COPY.
+COPY gtest1 FROM stdin;
+COPY gtest1 (a, b) FROM stdin;
+ERROR:  column "b" is a generated column
+DETAIL:  Generated columns cannot be used in COPY.
+SELECT * FROM gtest1 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
+TRUNCATE gtest3;
+INSERT INTO gtest3 (a) VALUES (1), (2);
+COPY gtest3 TO stdout;
+1
+2
+COPY gtest3 (a, b) TO stdout;
+ERROR:  column "b" is a generated column
+DETAIL:  Generated columns cannot be used in COPY.
+COPY gtest3 FROM stdin;
+COPY gtest3 (a, b) FROM stdin;
+ERROR:  column "b" is a generated column
+DETAIL:  Generated columns cannot be used in COPY.
+SELECT * FROM gtest3 ORDER BY a;
+ a | b  
+---+----
+ 1 |  3
+ 2 |  6
+ 3 |  9
+ 4 | 12
+(4 rows)
+
+-- null values
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
+INSERT INTO gtest2 VALUES (1);
+SELECT * FROM gtest2;
+ a | b 
+---+---
+ 1 |  
+(1 row)
+
+-- simple column reference for varlena types
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
+INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
+INSERT INTO gtest_varlena (a) VALUES(NULL);
+SELECT * FROM gtest_varlena ORDER BY a;
+          a           |          b           
+----------------------+----------------------
+ 01234567890123456789 | 01234567890123456789
+                      | 
+(2 rows)
+
+DROP TABLE gtest_varlena;
+-- composite types
+CREATE TYPE double_int as (a int, b int);
+CREATE TABLE gtest4 (
+    a int,
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
+);
+INSERT INTO gtest4 VALUES (1), (6);
+SELECT * FROM gtest4;
+ a |    b    
+---+---------
+ 1 | (2,3)
+ 6 | (12,18)
+(2 rows)
+
+DROP TABLE gtest4;
+DROP TYPE double_int;
+-- using tableoid is allowed
+CREATE TABLE gtest_tableoid (
+  a int PRIMARY KEY,
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
+);
+INSERT INTO gtest_tableoid VALUES (1), (2);
+ALTER TABLE gtest_tableoid ADD COLUMN
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
+SELECT * FROM gtest_tableoid;
+ a | b |       c        
+---+---+----------------
+ 1 | t | gtest_tableoid
+ 2 | t | gtest_tableoid
+(2 rows)
+
+-- drop column behavior
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+ALTER TABLE gtest10 DROP COLUMN b;  -- fails
+ERROR:  cannot drop column b of table gtest10 because other objects depend on it
+DETAIL:  column c of table gtest10 depends on column b of table gtest10
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
+ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
+NOTICE:  drop cascades to column c of table gtest10
+\d gtest10
+      Table "generated_virtual_tests.gtest10"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           | not null | 
+Indexes:
+    "gtest10_pkey" PRIMARY KEY, btree (a)
+
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest10a DROP COLUMN b;
+INSERT INTO gtest10a (a) VALUES (1);
+-- privileges
+CREATE USER regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
+CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
+REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
+SET ROLE regress_user11;
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
+ a | c  
+---+----
+ 1 | 20
+ 2 | 40
+(2 rows)
+
+SELECT gf1(10);  -- not allowed
+ERROR:  permission denied for function gf1
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
+RESET ROLE;
+DROP FUNCTION gf1(int);  -- fail
+ERROR:  cannot drop function gf1(integer) because other objects depend on it
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
+DROP TABLE gtest11v, gtest12v;
+DROP FUNCTION gf1(int);
+DROP USER regress_user11;
+-- check constraints
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
+INSERT INTO gtest20 (a) VALUES (10);  -- ok
+INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
+ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
+DETAIL:  Failing row contains (30, virtual).
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+INSERT INTO gtest20a (a) VALUES (10);
+INSERT INTO gtest20a (a) VALUES (30);
+ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
+ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+INSERT INTO gtest20b (a) VALUES (10);
+INSERT INTO gtest20b (a) VALUES (30);
+ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
+ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
+ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+-- index constraints
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
+-- indexes
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
+-- foreign keys
+CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
+-- domains
+CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
+-- typed tables (currently not supported)
+CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
+ERROR:  generated columns are not supported on typed tables
+DROP TYPE gtest_type CASCADE;
+-- partitioning cases
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_child PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
+) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
+ERROR:  child column "f3" specifies generation expression
+HINT:  A child table column cannot be generated unless its parent column is.
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
+ERROR:  column "f3" in child table must not be a generated column
+DROP TABLE gtest_parent, gtest_child;
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_child PARTITION OF gtest_parent
+  FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
+CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
+) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 DEFAULT 42  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column but specifies default
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" in child table must be a generated column
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" in child table must be a generated column
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  table "gtest_child3" being attached contains an identity column "f3"
+DETAIL:  The new partition may not contain an identity column.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+\d gtest_child
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 2)
+Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
+
+\d gtest_child2
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 22)
+Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
+
+\d gtest_child3
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 33)
+Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
+
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child  | 07-15-2016 |  1 |  2
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+(3 rows)
+
+UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
+(3 rows)
+
+-- alter only parent's and one child's generation expression
+ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
+ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
+\d gtest_parent
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 2)
+Partition key: RANGE (f1)
+Number of partitions: 3 (Use \d+ to list them.)
+
+\d gtest_child
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 2)
+Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
+
+\d gtest_child2
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 22)
+Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
+
+\d gtest_child3
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 33)
+Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
+
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
+(3 rows)
+
+-- alter generation expression of parent and all its children altogether
+ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
+\d gtest_parent
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 2)
+Partition key: RANGE (f1)
+Number of partitions: 3 (Use \d+ to list them.)
+
+\d gtest_child
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 2)
+Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
+
+\d gtest_child2
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 22)
+Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
+
+\d gtest_child3
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
+ f1     | date   |           | not null | 
+ f2     | bigint |           |          | 
+ f3     | bigint |           |          | generated always as (f2 * 33)
+Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
+
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
+(3 rows)
+
+-- we leave these tables around for purposes of testing dump/reload/upgrade
+-- generated columns in partition key (not allowed)
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+ERROR:  cannot use generated column in partition key
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+                                                                   ^
+DETAIL:  Column "f3" is a generated column.
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
+ERROR:  cannot use generated column in partition key
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
+                                                             ^
+DETAIL:  Column "f3" is a generated column.
+-- ALTER TABLE ... ADD COLUMN
+CREATE TABLE gtest25 (a int PRIMARY KEY);
+INSERT INTO gtest25 VALUES (3), (4);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
+SELECT * FROM gtest25 ORDER BY a;
+ a 
+---
+ 3
+ 4
+(2 rows)
+
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
+ERROR:  column "z" does not exist
+ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
+ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
+ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
+SELECT * FROM gtest25 ORDER BY a;
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
+(2 rows)
+
+\d gtest25
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
+ a      | integer          |           | not null | 
+ c      | integer          |           |          | 42
+ x      | integer          |           |          | generated always as (c * 4)
+ d      | double precision |           |          | 101
+ y      | double precision |           |          | generated always as (d * 4::double precision)
+Indexes:
+    "gtest25_pkey" PRIMARY KEY, btree (a)
+
+-- ALTER TABLE ... ALTER COLUMN
+CREATE TABLE gtest27 (
+    a int,
+    b int,
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
+);
+INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
+ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
+ERROR:  cannot alter type of a column used by a generated column
+DETAIL:  Column "a" is used by generated column "x".
+ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
+\d gtest27
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ x      | numeric |           |          | generated always as (((a + b) * 2))
+
+SELECT * FROM gtest27;
+ a | b  | x  
+---+----+----
+ 3 |  7 | 20
+ 4 | 11 | 30
+(2 rows)
+
+ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0;  -- error
+ERROR:  cannot specify USING when altering type of generated column
+DETAIL:  Column "x" is a generated column.
+ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
+ERROR:  column "x" of relation "gtest27" is a generated column
+-- It's possible to alter the column types this way:
+ALTER TABLE gtest27
+  DROP COLUMN x,
+  ALTER COLUMN a TYPE bigint,
+  ALTER COLUMN b TYPE bigint,
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
+\d gtest27
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
+ a      | bigint |           |          | 
+ b      | bigint |           |          | 
+ x      | bigint |           |          | generated always as ((a + b) * 2)
+
+-- Ideally you could just do this, but not today (and should x change type?):
+ALTER TABLE gtest27
+  ALTER COLUMN a TYPE float8,
+  ALTER COLUMN b TYPE float8;  -- error
+ERROR:  cannot alter type of a column used by a generated column
+DETAIL:  Column "a" is used by generated column "x".
+\d gtest27
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
+ a      | bigint |           |          | 
+ b      | bigint |           |          | 
+ x      | bigint |           |          | generated always as ((a + b) * 2)
+
+SELECT * FROM gtest27;
+ a | b  | x  
+---+----+----
+ 3 |  7 | 20
+ 4 | 11 | 30
+(2 rows)
+
+-- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
+CREATE TABLE gtest29 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtest29 (a) VALUES (3), (4);
+SELECT * FROM gtest29;
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
+(2 rows)
+
+\d gtest29
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+
+ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
+ERROR:  column "a" of relation "gtest29" is not a generated column
+ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
+ERROR:  column "a" of relation "gtest29" is not a generated column
+ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
+-- Change the expression
+ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
+SELECT * FROM gtest29;
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
+(2 rows)
+
+\d gtest29
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
+INSERT INTO gtest29 (a) VALUES (5);
+INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
+SELECT * FROM gtest29;
+ a | b  
+---+----
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
+
+\d gtest29
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+
+-- check that dependencies between columns have also been removed
+ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
+\d gtest29
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+
+-- with inheritance
+CREATE TABLE gtest30 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+CREATE TABLE gtest30_1 () INHERITS (gtest30);
+ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
+\d gtest30
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d gtest30_1
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+Inherits: gtest30
+
+DROP TABLE gtest30 CASCADE;
+NOTICE:  drop cascades to table gtest30_1
+CREATE TABLE gtest30 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+CREATE TABLE gtest30_1 () INHERITS (gtest30);
+ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
+ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
+\d gtest30
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+Number of child tables: 1 (Use \d+ to list them.)
+
+\d gtest30_1
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
+Inherits: gtest30
+
+ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
+ERROR:  cannot drop generation expression from inherited column
+-- triggers
+CREATE TABLE gtest26 (
+    a int PRIMARY KEY,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+CREATE FUNCTION gtest_trigger_func() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  IF tg_op IN ('DELETE', 'UPDATE') THEN
+    RAISE INFO '%: %: old = %', TG_NAME, TG_WHEN, OLD;
+  END IF;
+  IF tg_op IN ('INSERT', 'UPDATE') THEN
+    RAISE INFO '%: %: new = %', TG_NAME, TG_WHEN, NEW;
+  END IF;
+  IF tg_op = 'DELETE' THEN
+    RETURN OLD;
+  ELSE
+    RETURN NEW;
+  END IF;
+END
+$$;
+CREATE TRIGGER gtest1 BEFORE DELETE OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (OLD.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+CREATE TRIGGER gtest2a BEFORE INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.b < 0)  -- error
+  EXECUTE PROCEDURE gtest_trigger_func();
+ERROR:  BEFORE trigger's WHEN condition cannot reference NEW generated columns
+LINE 3:   WHEN (NEW.b < 0)  -- error
+                ^
+DETAIL:  Column "b" is a generated column.
+CREATE TRIGGER gtest2b BEFORE INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.* IS NOT NULL)  -- error
+  EXECUTE PROCEDURE gtest_trigger_func();
+ERROR:  BEFORE trigger's WHEN condition cannot reference NEW generated columns
+LINE 3:   WHEN (NEW.* IS NOT NULL)  -- error
+                ^
+DETAIL:  A whole-row reference is used and the table contains generated columns.
+CREATE TRIGGER gtest2 BEFORE INSERT ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.a < 0)
+  EXECUTE PROCEDURE gtest_trigger_func();
+CREATE TRIGGER gtest3 AFTER DELETE OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (OLD.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
+INFO:  gtest2: BEFORE: new = (-2,)
+INFO:  gtest4: AFTER: new = (-2,)
+SELECT * FROM gtest26 ORDER BY a;
+ a  | b  
+----+----
+ -2 | -4
+  0 |  0
+  3 |  6
+(3 rows)
+
+UPDATE gtest26 SET a = a * -2;
+INFO:  gtest1: BEFORE: old = (-2,)
+INFO:  gtest1: BEFORE: new = (4,)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
+SELECT * FROM gtest26 ORDER BY a;
+ a  |  b  
+----+-----
+ -6 | -12
+  0 |   0
+  4 |   8
+(3 rows)
+
+DELETE FROM gtest26 WHERE a = -6;
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
+SELECT * FROM gtest26 ORDER BY a;
+ a | b 
+---+---
+ 0 | 0
+ 4 | 8
+(2 rows)
+
+DROP TRIGGER gtest1 ON gtest26;
+DROP TRIGGER gtest2 ON gtest26;
+DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
+-- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
+-- SQL standard.
+CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  RAISE NOTICE 'OK';
+  RETURN NEW;
+END
+$$;
+CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
+UPDATE gtest26 SET a = 1 WHERE a = 0;
+DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
+TRUNCATE gtest26;
+-- check that modifications of stored generated columns in triggers do
+-- not get propagated
+CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  NEW.a = 10;
+  NEW.b = 300;
+  RETURN NEW;
+END;
+$$;
+CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func();
+CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func4();
+CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func();
+INSERT INTO gtest26 (a) VALUES (1);
+UPDATE gtest26 SET a = 11 WHERE a = 1;
+INFO:  gtest12_01: BEFORE: old = (1,)
+INFO:  gtest12_01: BEFORE: new = (11,)
+ERROR:  trigger modified virtual generated column value
+SELECT * FROM gtest26 ORDER BY a;
+ a | b 
+---+---
+ 1 | 2
+(1 row)
+
+-- LIKE INCLUDING GENERATED and dropped column handling
+CREATE TABLE gtest28a (
+  a int,
+  b int,
+  c int,
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
+);
+ALTER TABLE gtest28a DROP COLUMN a;
+CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
+\d gtest28*
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+ x      | integer |           |          | generated always as (b * 2)
+
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+ x      | integer |           |          | generated always as (b * 2)
+
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index f53a526f7c..2e56537f19 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -66,7 +66,10 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 # Another group of parallel tests
 # ----------
-test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated join_hash
+test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
+
+# TODO: find a place for this (above group is full)
+test: generated_virtual
 
 # ----------
 # Additional BRIN tests
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b..ddf893f7ec 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ INSERT INTO test_like_id_3 (b) VALUES ('b3');
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated.sql b/src/test/regress/sql/generated_stored.sql
similarity index 96%
rename from src/test/regress/sql/generated.sql
rename to src/test/regress/sql/generated_stored.sql
index cb55d77821..36a6c2bddb 100644
--- a/src/test/regress/sql/generated.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,13 +1,17 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
+CREATE SCHEMA generated_stored_tests;
+GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
+SET search_path = generated_stored_tests;
+
 CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
 CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_name LIKE 'gtest_' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
@@ -99,6 +103,14 @@ MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -386,6 +398,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
new file mode 100644
index 0000000000..2bb9e1b45f
--- /dev/null
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -0,0 +1,726 @@
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+
+
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
+
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
+
+\d gtest1
+
+-- duplicate generated
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
+
+-- references to other generated columns, including self-references
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
+-- a whole-row var is a self-reference on steroids, so disallow that too
+CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
+
+-- invalid reference
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
+
+-- generation expression must be immutable
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
+-- ... but be sure that the immutability test is accurate
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
+DROP TABLE gtest2;
+
+-- cannot have default/identity and generated
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
+
+-- reference to system column not allowed in generated column
+-- (except tableoid, which we test below)
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
+
+-- various prohibited constructs
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
+
+-- GENERATED BY DEFAULT not allowed
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
+
+INSERT INTO gtest1 VALUES (1);
+INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
+INSERT INTO gtest1 VALUES (3, 33);  -- error
+INSERT INTO gtest1 VALUES (3, 33), (4, 44);  -- error
+INSERT INTO gtest1 VALUES (3, DEFAULT), (4, 44);  -- error
+INSERT INTO gtest1 VALUES (3, 33), (4, DEFAULT);  -- error
+INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
+
+SELECT * FROM gtest1 ORDER BY a;
+DELETE FROM gtest1 WHERE a >= 3;
+
+UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
+UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
+
+SELECT * FROM gtest1 ORDER BY a;
+
+SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
+SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
+
+-- test that overflow error happens on read
+INSERT INTO gtest1 VALUES (2000000000);
+SELECT * FROM gtest1;
+DELETE FROM gtest1 WHERE a = 2000000000;
+
+-- test with joins
+CREATE TABLE gtestx (x int, y int);
+INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
+SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+DROP TABLE gtestx;
+
+-- test UPDATE/DELETE quals
+SELECT * FROM gtest1 ORDER BY a;
+UPDATE gtest1 SET a = 3 WHERE b = 4;
+SELECT * FROM gtest1 ORDER BY a;
+DELETE FROM gtest1 WHERE b = 2;
+SELECT * FROM gtest1 ORDER BY a;
+
+-- test MERGE
+CREATE TABLE gtestm (
+  id int PRIMARY KEY,
+  f1 int,
+  f2 int,
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
+);
+INSERT INTO gtestm VALUES (1, 5, 100);
+MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
+  WHEN MATCHED THEN UPDATE SET f1 = v.f1
+  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200);
+SELECT * FROM gtestm ORDER BY id;
+DROP TABLE gtestm;
+
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
+-- views
+CREATE VIEW gtest1v AS SELECT * FROM gtest1;
+SELECT * FROM gtest1v;
+INSERT INTO gtest1v VALUES (4, 8);  -- error
+INSERT INTO gtest1v VALUES (5, DEFAULT);  -- ok
+INSERT INTO gtest1v VALUES (6, 66), (7, 77);  -- error
+INSERT INTO gtest1v VALUES (6, DEFAULT), (7, 77);  -- error
+INSERT INTO gtest1v VALUES (6, 66), (7, DEFAULT);  -- error
+INSERT INTO gtest1v VALUES (6, DEFAULT), (7, DEFAULT);  -- ok
+
+ALTER VIEW gtest1v ALTER COLUMN b SET DEFAULT 100;
+INSERT INTO gtest1v VALUES (8, DEFAULT);  -- error
+INSERT INTO gtest1v VALUES (8, DEFAULT), (9, DEFAULT);  -- error
+
+SELECT * FROM gtest1v;
+DELETE FROM gtest1v WHERE a >= 5;
+DROP VIEW gtest1v;
+
+-- CTEs
+WITH foo AS (SELECT * FROM gtest1) SELECT * FROM foo;
+
+-- inheritance
+CREATE TABLE gtest1_1 () INHERITS (gtest1);
+SELECT * FROM gtest1_1;
+\d gtest1_1
+INSERT INTO gtest1_1 VALUES (4);
+SELECT * FROM gtest1_1;
+SELECT * FROM gtest1;
+
+-- can't have generated column that is a child of normal column
+CREATE TABLE gtest_normal (a int, b int);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
+DROP TABLE gtest_normal, gtest_normal_child;
+
+-- test inheritance mismatches between parent and child
+CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
+\d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
+
+CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
+ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
+ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
+
+-- test multiple inheritance mismatches
+CREATE TABLE gtesty (x int, b int DEFAULT 55);
+CREATE TABLE gtest1_y () INHERITS (gtest0, gtesty);  -- error
+DROP TABLE gtesty;
+
+CREATE TABLE gtesty (x int, b int);
+CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
+DROP TABLE gtesty;
+
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
+CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
+\d gtest1_y
+
+-- test correct handling of GENERATED column that's only in child
+CREATE TABLE gtestp (f1 int);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
+INSERT INTO gtestc values(42);
+TABLE gtestc;
+UPDATE gtestp SET f1 = f1 * 10;
+TABLE gtestc;
+DROP TABLE gtestp CASCADE;
+
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
+INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
+SELECT * FROM gtest3 ORDER BY a;
+UPDATE gtest3 SET a = 22 WHERE a = 2;
+SELECT * FROM gtest3 ORDER BY a;
+
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
+INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
+SELECT * FROM gtest3a ORDER BY a;
+UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
+SELECT * FROM gtest3a ORDER BY a;
+
+-- COPY
+TRUNCATE gtest1;
+INSERT INTO gtest1 (a) VALUES (1), (2);
+
+COPY gtest1 TO stdout;
+
+COPY gtest1 (a, b) TO stdout;
+
+COPY gtest1 FROM stdin;
+3
+4
+\.
+
+COPY gtest1 (a, b) FROM stdin;
+
+SELECT * FROM gtest1 ORDER BY a;
+
+TRUNCATE gtest3;
+INSERT INTO gtest3 (a) VALUES (1), (2);
+
+COPY gtest3 TO stdout;
+
+COPY gtest3 (a, b) TO stdout;
+
+COPY gtest3 FROM stdin;
+3
+4
+\.
+
+COPY gtest3 (a, b) FROM stdin;
+
+SELECT * FROM gtest3 ORDER BY a;
+
+-- null values
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
+INSERT INTO gtest2 VALUES (1);
+SELECT * FROM gtest2;
+
+-- simple column reference for varlena types
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
+INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
+INSERT INTO gtest_varlena (a) VALUES(NULL);
+SELECT * FROM gtest_varlena ORDER BY a;
+DROP TABLE gtest_varlena;
+
+-- composite types
+CREATE TYPE double_int as (a int, b int);
+CREATE TABLE gtest4 (
+    a int,
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
+);
+INSERT INTO gtest4 VALUES (1), (6);
+SELECT * FROM gtest4;
+
+DROP TABLE gtest4;
+DROP TYPE double_int;
+
+-- using tableoid is allowed
+CREATE TABLE gtest_tableoid (
+  a int PRIMARY KEY,
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
+);
+INSERT INTO gtest_tableoid VALUES (1), (2);
+ALTER TABLE gtest_tableoid ADD COLUMN
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
+SELECT * FROM gtest_tableoid;
+
+-- drop column behavior
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+ALTER TABLE gtest10 DROP COLUMN b;  -- fails
+ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
+
+\d gtest10
+
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest10a DROP COLUMN b;
+INSERT INTO gtest10a (a) VALUES (1);
+
+-- privileges
+CREATE USER regress_user11;
+
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
+
+CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
+REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
+
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+
+SET ROLE regress_user11;
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
+SELECT gf1(10);  -- not allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+RESET ROLE;
+
+DROP FUNCTION gf1(int);  -- fail
+DROP TABLE gtest11v, gtest12v;
+DROP FUNCTION gf1(int);
+DROP USER regress_user11;
+
+-- check constraints
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
+INSERT INTO gtest20 (a) VALUES (10);  -- ok
+INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
+
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+INSERT INTO gtest20a (a) VALUES (10);
+INSERT INTO gtest20a (a) VALUES (30);
+ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
+
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+INSERT INTO gtest20b (a) VALUES (10);
+INSERT INTO gtest20b (a) VALUES (30);
+ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
+ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
+
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+
+-- index constraints
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
+
+-- indexes
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
+
+-- foreign keys
+CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
+
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
+
+CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
+
+-- domains
+CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
+
+-- typed tables (currently not supported)
+CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
+DROP TYPE gtest_type CASCADE;
+
+-- partitioning cases
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_child PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
+) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
+DROP TABLE gtest_parent, gtest_child;
+
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_child PARTITION OF gtest_parent
+  FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
+CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
+) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 DEFAULT 42  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+\d gtest_child
+\d gtest_child2
+\d gtest_child3
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
+INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+
+-- alter only parent's and one child's generation expression
+ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+\d gtest_parent
+\d gtest_child
+\d gtest_child2
+\d gtest_child3
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+
+-- alter generation expression of parent and all its children altogether
+ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+\d gtest_parent
+\d gtest_child
+\d gtest_child2
+\d gtest_child3
+SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+-- we leave these tables around for purposes of testing dump/reload/upgrade
+
+-- generated columns in partition key (not allowed)
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
+
+-- ALTER TABLE ... ADD COLUMN
+CREATE TABLE gtest25 (a int PRIMARY KEY);
+INSERT INTO gtest25 VALUES (3), (4);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+SELECT * FROM gtest25 ORDER BY a;
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
+ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
+ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
+SELECT * FROM gtest25 ORDER BY a;
+\d gtest25
+
+-- ALTER TABLE ... ALTER COLUMN
+CREATE TABLE gtest27 (
+    a int,
+    b int,
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
+);
+INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
+ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
+ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
+\d gtest27
+SELECT * FROM gtest27;
+ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0;  -- error
+ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
+-- It's possible to alter the column types this way:
+ALTER TABLE gtest27
+  DROP COLUMN x,
+  ALTER COLUMN a TYPE bigint,
+  ALTER COLUMN b TYPE bigint,
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
+\d gtest27
+-- Ideally you could just do this, but not today (and should x change type?):
+ALTER TABLE gtest27
+  ALTER COLUMN a TYPE float8,
+  ALTER COLUMN b TYPE float8;  -- error
+\d gtest27
+SELECT * FROM gtest27;
+
+-- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
+CREATE TABLE gtest29 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtest29 (a) VALUES (3), (4);
+SELECT * FROM gtest29;
+\d gtest29
+ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
+ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
+ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
+
+-- Change the expression
+ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+SELECT * FROM gtest29;
+\d gtest29
+
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+INSERT INTO gtest29 (a) VALUES (5);
+INSERT INTO gtest29 (a, b) VALUES (6, 66);
+SELECT * FROM gtest29;
+\d gtest29
+
+-- check that dependencies between columns have also been removed
+ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+\d gtest29
+
+-- with inheritance
+CREATE TABLE gtest30 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+CREATE TABLE gtest30_1 () INHERITS (gtest30);
+ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+\d gtest30
+\d gtest30_1
+DROP TABLE gtest30 CASCADE;
+CREATE TABLE gtest30 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+CREATE TABLE gtest30_1 () INHERITS (gtest30);
+ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
+\d gtest30
+\d gtest30_1
+ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
+
+-- triggers
+CREATE TABLE gtest26 (
+    a int PRIMARY KEY,
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+
+CREATE FUNCTION gtest_trigger_func() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  IF tg_op IN ('DELETE', 'UPDATE') THEN
+    RAISE INFO '%: %: old = %', TG_NAME, TG_WHEN, OLD;
+  END IF;
+  IF tg_op IN ('INSERT', 'UPDATE') THEN
+    RAISE INFO '%: %: new = %', TG_NAME, TG_WHEN, NEW;
+  END IF;
+  IF tg_op = 'DELETE' THEN
+    RETURN OLD;
+  ELSE
+    RETURN NEW;
+  END IF;
+END
+$$;
+
+CREATE TRIGGER gtest1 BEFORE DELETE OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (OLD.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest2a BEFORE INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.b < 0)  -- error
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest2b BEFORE INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.* IS NOT NULL)  -- error
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest2 BEFORE INSERT ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.a < 0)
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest3 AFTER DELETE OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (OLD.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
+  FOR EACH ROW
+  WHEN (NEW.b < 0)  -- ok
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
+SELECT * FROM gtest26 ORDER BY a;
+UPDATE gtest26 SET a = a * -2;
+SELECT * FROM gtest26 ORDER BY a;
+DELETE FROM gtest26 WHERE a = -6;
+SELECT * FROM gtest26 ORDER BY a;
+
+DROP TRIGGER gtest1 ON gtest26;
+DROP TRIGGER gtest2 ON gtest26;
+DROP TRIGGER gtest3 ON gtest26;
+
+-- check disallowed modification of virtual columns
+-- TODO
+
+-- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
+-- SQL standard.
+CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  RAISE NOTICE 'OK';
+  RETURN NEW;
+END
+$$;
+
+CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func3();
+
+UPDATE gtest26 SET a = 1 WHERE a = 0;
+
+DROP TRIGGER gtest11 ON gtest26;
+TRUNCATE gtest26;
+
+-- check that modifications of stored generated columns in triggers do
+-- not get propagated
+CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
+  LANGUAGE plpgsql
+AS $$
+BEGIN
+  NEW.a = 10;
+  NEW.b = 300;
+  RETURN NEW;
+END;
+$$;
+
+CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func4();
+
+CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+  FOR EACH ROW
+  EXECUTE PROCEDURE gtest_trigger_func();
+
+INSERT INTO gtest26 (a) VALUES (1);
+UPDATE gtest26 SET a = 11 WHERE a = 1;
+SELECT * FROM gtest26 ORDER BY a;
+
+-- LIKE INCLUDING GENERATED and dropped column handling
+CREATE TABLE gtest28a (
+  a int,
+  b int,
+  c int,
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
+);
+
+ALTER TABLE gtest28a DROP COLUMN a;
+
+CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
+
+\d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
+
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708..faee155daa 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@ $node_subscriber->start;
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@ $node_subscriber->safe_psql('postgres',
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@ $node_publisher->safe_psql('postgres', "UPDATE tab1 SET a = 6 WHERE a = 5");
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@ $node_subscriber->safe_psql(
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ $node_publisher->wait_for_catchup('sub1');
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();
-- 
2.34.1

From 5a73fb029cc215134d0213c06ede10a3a42b755b Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 29 Aug 2024 11:49:48 +0200
Subject: [PATCH v4] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 124 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/analyze.c                  |   8 +
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_clause.c             |   4 +
 src/backend/parser/parse_merge.c              |   1 +
 src/backend/parser/parse_relation.c           |   9 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 171 +++-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   3 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/parser/parse_node.h               |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |  32 +-
 ...rated_stored.out => generated_virtual.out} | 871 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |  14 +-
 ...rated_stored.sql => generated_virtual.sql} | 336 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 58 files changed, 1391 insertions(+), 710 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (69%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60a..7e0b09e279b 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b5..186dda1e8d0 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f3eb055e2c7..926c1fddbe3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0734716ad90..058d53364db 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index b654fae1b2f..579b1d61660 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index b671858627b..378ae934baa 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 1a49f321cf7..c5aaf765446 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -264,6 +264,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -276,10 +281,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f21..ee79867d969 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2e..5953d24ae8f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1c6da286d43..0c95a11f044 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2048,6 +2048,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 01b43cc6a84..29358f37307 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 902eb1a4508..f79ff40c3ec 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1030,6 +1030,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c5a56c75f69..ec4e8bc3902 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 70cd2669164..2f83274daac 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2936,6 +2936,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3207,6 +3216,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -5986,7 +6004,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7704,6 +7722,14 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
@@ -8301,7 +8327,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8458,17 +8495,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8611,6 +8661,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9690,6 +9750,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11671,7 +11744,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12722,8 +12795,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -12796,11 +12873,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -15758,6 +15836,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -17884,8 +17970,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -17967,9 +18056,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 170360edda8..021328746a1 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2502,6 +2512,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3059,6 +3071,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3489,6 +3503,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6596,3 +6611,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 77394e76c37..58b0f2f76d6 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2119,6 +2119,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 29e186fa73d..a49b1e821e0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1743,6 +1743,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2290,7 +2291,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e901203424d..e3936a0b8ea 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,6 +568,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -994,6 +995,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1459,6 +1461,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1685,6 +1688,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1936,6 +1940,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2410,6 +2415,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2477,6 +2483,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2843,6 +2850,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 84cef57a707..18ce875c406 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -640,7 +640,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -788,7 +788,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3973,7 +3973,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3981,6 +3981,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4027,6 +4028,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17809,6 +17816,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18462,6 +18470,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495b..48524ac3fc2 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 87df79027d7..350e9e18885 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,6 +405,7 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e37..b864749f09c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 79cad4ab30c..03301f9c53e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -751,7 +751,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -839,6 +839,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index abef4eaf68b..52dc9b5fcac 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index c223a2c50af..03b4b857ed1 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -44,6 +44,7 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 
 
 /* We use a list of these to detect recursion in RewriteQuery */
@@ -90,6 +91,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
 
 
 /*
@@ -974,7 +977,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4365,6 +4369,168 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Virtual generated columns support
+ */
+
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+
+	/* incremented for every level where it's true */
+	int			ancestor_has_virtual;
+};
+
+static Node *
+expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			Oid			attcollid;
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+
+			/*
+			 * If the column definition has a collation and it is different
+			 * from the collation of the generation expression, put a COLLATE
+			 * clause around the expression.
+			 */
+			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+			if (attcollid && attcollid != exprCollation(node))
+			{
+				CollateExpr *ce = makeNode(CollateExpr);
+
+				ce->arg = (Expr *) node;
+				ce->collOid = attcollid;
+				ce->location = -1;
+
+				node = (Node *) ce;
+			}
+
+			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+		List	   *rtable;
+		struct expand_generated_context context;
+
+		/*
+		 * Make a dummy range table for a single relation.  For the benefit of
+		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
+		 * PRS2_NEW_VARNO.
+		 */
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		rtable = list_make2(rte, rte);
+		context.rtables = list_make1(rtable);
+
+		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
+	}
+	else
+		return node;
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4409,9 +4575,12 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
+		struct expand_generated_context context = {0};
 
 		query = fireRIRrules(query, NIL);
 
+		query = expand_generated_columns_in_query(query, &context);
+
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 66ed24e4012..4f756acd39d 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index b6e01d3d292..4b2aac8cd33 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15998,6 +15998,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 5bcc2244d58..c3d6022015c 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 7c9a1f234c6..4309d3e757d 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index c512824cd1c..235ad73eedc 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 124d853e499..355f52199fa 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2730,6 +2732,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f8659078ced..6416f9b110b 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -489,6 +489,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9d..1b02128548b 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be345..9611aa82352 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 21b2b045933..cb715ad08b6 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 8ea8a3a92d2..8f0951e26a7 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -217,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -762,6 +783,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -1092,9 +1118,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 8ea8a3a92d2..4cf4f8118f3 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +211,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +288,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +311,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +327,42 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +375,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +413,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +435,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +500,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +509,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +524,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +539,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +552,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +560,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +593,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +738,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +756,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +793,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +801,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +908,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +963,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +971,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1033,20 +990,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1055,12 +1011,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1072,7 +1028,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1083,107 +1039,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1191,7 +1158,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1244,7 +1211,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1254,12 +1221,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1269,8 +1236,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1281,6 +1248,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1294,9 +1263,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1320,14 +1291,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1335,22 +1305,77 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 7a5a910562e..2e56537f194 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..36a6c2bddbe 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -390,6 +398,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 69%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..34b8070b3e3 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +142,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +173,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +234,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +249,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +260,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +433,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +445,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +476,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +498,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +512,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +524,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +551,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +560,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +633,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +689,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +697,47 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
+
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();

base-commit: 894be11adfa60ad1ce5f74534cf5f04e66d51c30
-- 
2.46.0

From 8f0e74efdb4ae92f6b0a27d2446688461f7346f5 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 29 Aug 2024 21:22:06 +0800
Subject: [PATCH v4 1/1] Virtual generated columns

address the get_attgenerated overhead.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 src/backend/rewrite/rewriteHandler.c | 135 +++++++++++++++++++--------
 1 file changed, 98 insertions(+), 37 deletions(-)

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index f2713eaef2..d4da0178f2 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -4380,6 +4380,12 @@ struct expand_generated_context
 
 	/* incremented for every level where it's true */
 	int			ancestor_has_virtual;
+
+	/* list of relation oids that have virtual generated column */
+	List		*virtual_gen_rel;
+
+	/* list of attnums that have virtual generated column */
+	List		*virtual_attnums;
 };
 
 static Node *
@@ -4393,6 +4399,9 @@ expand_generated_columns_mutator(Node *node, struct expand_generated_context *co
 		Var		   *v = (Var *) node;
 		Oid			relid;
 		AttrNumber	attnum;
+		ListCell   *lc,
+				   *lc2;
+		Oid			attcollid;
 		List	   *rtable = list_nth_node(List,
 										   context->rtables,
 										   list_length(context->rtables) - v->varlevelsup - 1);
@@ -4403,39 +4412,45 @@ expand_generated_columns_mutator(Node *node, struct expand_generated_context *co
 		if (!relid || !attnum)
 			return node;
 
-		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		forboth(lc, context->virtual_gen_rel, lc2, context->virtual_attnums)
 		{
-			Relation	rt_entry_relation = table_open(relid, NoLock);
-			Oid			attcollid;
+			Oid	 virtual_rel = lfirst_oid(lc);
+			AttrNumber	attno = lfirst_int(lc2);
 
-			node = build_column_default(rt_entry_relation, attnum);
-			if (node == NULL)
-				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
-					 attnum, RelationGetRelationName(rt_entry_relation));
-
-			/*
-			 * If the column definition has a collation and it is different
-			 * from the collation of the generation expression, put a COLLATE
-			 * clause around the expression.
-			 */
-			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
-			if (attcollid && attcollid != exprCollation(node))
+			if(attno == attnum && virtual_rel == relid)
 			{
-				CollateExpr *ce = makeNode(CollateExpr);
+				Relation	rt_entry_relation = table_open(relid, NoLock);
 
-				ce->arg = (Expr *) node;
-				ce->collOid = attcollid;
-				ce->location = -1;
+				Assert(get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL);
 
-				node = (Node *) ce;
+				node = build_column_default(rt_entry_relation, attnum);
+				if (node == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						attnum, RelationGetRelationName(rt_entry_relation));
+
+				/*
+				* If the column definition has a collation and it is different
+				* from the collation of the generation expression, put a COLLATE
+				* clause around the expression.
+				*/
+				attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+				if (attcollid && attcollid != exprCollation(node))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) node;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					node = (Node *) ce;
+				}
+
+				IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+				ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+				table_close(rt_entry_relation, NoLock);
 			}
-
-			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
-			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
-
-			table_close(rt_entry_relation, NoLock);
 		}
-
 		return node;
 	}
 	else if (IsA(node, Query))
@@ -4457,6 +4472,7 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 
 	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
+		int	i;
 		RangeTblEntry *rte;
 		List	   *rtable;
 		struct expand_generated_context context;
@@ -4470,6 +4486,23 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 		rte->relid = RelationGetRelid(rel);
 		rtable = list_make2(rte, rte);
 		context.rtables = list_make1(rtable);
+		context.virtual_gen_rel = NIL;
+		context.virtual_attnums = NIL;
+
+		for (i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+			if (att->attisdropped)
+				continue;
+
+			if (att->attgenerated == 'v')
+			{
+				context.virtual_gen_rel = lappend_oid(context.virtual_gen_rel, rte->relid);
+				context.virtual_attnums = lappend_int(context.virtual_attnums, att->attnum);
+			}
+		}
+		Assert(list_length(context.virtual_gen_rel) > 0);
+		Assert(list_length(context.virtual_gen_rel) == list_length(context.virtual_attnums));
 
 		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
 	}
@@ -4486,13 +4519,49 @@ expand_generated_columns_in_query(Query *query, struct expand_generated_context
 {
 	context->rtables = lappend(context->rtables, query->rtable);
 	if (query->hasGeneratedVirtual)
+	{
+		List		*rte_relids = NIL;
 		context->ancestor_has_virtual++;
+		context->ancestor_has_virtual++;
+
+		foreach_node(RangeTblEntry, rte, query->rtable)
+		{
+			if(OidIsValid(rte->relid))
+				rte_relids = list_append_unique_oid(rte_relids, rte->relid);
+		}
+
+		foreach_oid(relid, rte_relids)
+		{
+			int	i;
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			TupleDesc	tupdesc = RelationGetDescr(rt_entry_relation);
+
+			if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+			{
+				for (i = 0; i < tupdesc->natts; i++)
+				{
+					Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+					if (att->attisdropped)
+						continue;
+
+					if (att->attgenerated == 'v')
+					{
+						context->virtual_gen_rel = lappend_oid(context->virtual_gen_rel, relid);
+						context->virtual_attnums = lappend_int(context->virtual_attnums, att->attnum);
+					}
+				}
+				Assert(list_length(context->virtual_gen_rel) > 0);
+				Assert(list_length(context->virtual_gen_rel) == list_length(context->virtual_attnums));
+			}
+			table_close(rt_entry_relation, NoLock);
+		}
 
+	}
 	/*
 	 * If any table in the query has a virtual column or there is a sublink,
 	 * then we need to do the whole walk.
 	 */
-	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	if (context->ancestor_has_virtual)
 	{
 		query = query_tree_mutator(query,
 								   expand_generated_columns_mutator,
@@ -4505,22 +4574,14 @@ expand_generated_columns_in_query(Query *query, struct expand_generated_context
 	 */
 	else
 	{
-		ListCell   *lc;
-
-		foreach(lc, query->rtable)
+		foreach_node(RangeTblEntry, rte, query->rtable)
 		{
-			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
-
 			if (rte->rtekind == RTE_SUBQUERY)
 				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
 		}
 
-		foreach(lc, query->cteList)
-		{
-			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
-
+		foreach_node(CommonTableExpr, cte, query->cteList)
 			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
-		}
 	}
 
 	if (query->hasGeneratedVirtual)
-- 
2.34.1

From 748721898e8171d35d54ffe2b6edb38b9f5b020d Mon Sep 17 00:00:00 2001
From: Nazir Bilal Yavuz <byavuz81@gmail.com>
Date: Mon, 2 Sep 2024 16:18:57 +0300
Subject: [PATCH v1] Fix xid_wraparound/002_limits test

Error message used in xid_wraparound/002_limits is updated in edee0c621d.
Apply the same update in the test file as well.
---
 src/test/modules/xid_wraparound/t/002_limits.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/modules/xid_wraparound/t/002_limits.pl b/src/test/modules/xid_wraparound/t/002_limits.pl
index aca3fa15149..889689d3bde 100644
--- a/src/test/modules/xid_wraparound/t/002_limits.pl
+++ b/src/test/modules/xid_wraparound/t/002_limits.pl
@@ -103,7 +103,7 @@ $ret = $node->psql(
 	stderr => \$stderr);
 like(
 	$stderr,
-	qr/ERROR:  database is not accepting commands that assign new XIDs to avoid wraparound data loss in database "postgres"/,
+	qr/ERROR:  database is not accepting commands that assign new transaction IDs to avoid wraparound data loss in database "postgres"/,
 	"stop-limit");
 
 # Finish the old transaction, to allow vacuum freezing to advance
-- 
2.45.2

From 478660db3b96e9bb12adc7131c35b26f52d26c78 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Tue, 3 Sep 2024 12:49:33 +0800
Subject: [PATCH v5 1/1] Virtual generated wholerow var and virtual checking
 optimization

1. make checking a var is references to a virtual generated column faster
2. make virtual generated column expand correct with wholerow var

The first is via Tuple constraint struct (TupleConstr) has_generated_virtual
boolean flag bit.  walk through the query tree, open each relation, check
has_generated_virtual flag.  If so, then collect it.

the second, see expand_generated_columns_mutator case when "attnum == 0"
---
 src/backend/rewrite/rewriteHandler.c          | 221 +++++++++++++++---
 .../regress/expected/generated_virtual.out    |  31 +++
 src/test/regress/sql/generated_virtual.sql    |   7 +
 3 files changed, 227 insertions(+), 32 deletions(-)

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index f2713eaef2..7985c79f29 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -4380,6 +4380,12 @@ struct expand_generated_context
 
 	/* incremented for every level where it's true */
 	int			ancestor_has_virtual;
+
+	/* list of relation oids that have virtual generated column */
+	List		*virtual_gen_rel;
+
+	/* list of attnums that is virtual generated column */
+	List		*virtual_attnums;
 };
 
 static Node *
@@ -4393,6 +4399,9 @@ expand_generated_columns_mutator(Node *node, struct expand_generated_context *co
 		Var		   *v = (Var *) node;
 		Oid			relid;
 		AttrNumber	attnum;
+		ListCell   *lc,
+				   *lc2;
+		Oid			attcollid;
 		List	   *rtable = list_nth_node(List,
 										   context->rtables,
 										   list_length(context->rtables) - v->varlevelsup - 1);
@@ -4400,42 +4409,116 @@ expand_generated_columns_mutator(Node *node, struct expand_generated_context *co
 		relid = rt_fetch(v->varno, rtable)->relid;
 		attnum = v->varattno;
 
-		if (!relid || !attnum)
+		if (!OidIsValid(relid))
 			return node;
 
-		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		/* wholerow case when some individual var is virtual generated */
+		if (attnum == 0)
 		{
 			Relation	rt_entry_relation = table_open(relid, NoLock);
-			Oid			attcollid;
+			TupleDesc	tupdesc = RelationGetDescr(rt_entry_relation);
+			Node		*virtual_node = NULL;
+			RowExpr    *rowexpr =  NULL;
+			List	   *fields = NIL;
+			int			i;
 
-			node = build_column_default(rt_entry_relation, attnum);
-			if (node == NULL)
-				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
-					 attnum, RelationGetRelationName(rt_entry_relation));
+			if (tupdesc->constr && !tupdesc->constr->has_generated_virtual)
+			{
+				table_close(rt_entry_relation, NoLock);
+				return node;
+			}
 
-			/*
-			 * If the column definition has a collation and it is different
-			 * from the collation of the generation expression, put a COLLATE
-			 * clause around the expression.
-			 */
-			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
-			if (attcollid && attcollid != exprCollation(node))
+			for (i = 0; i < tupdesc->natts; i++)
 			{
-				CollateExpr *ce = makeNode(CollateExpr);
+				Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+				if (att->attisdropped)
+					continue;	//TODO, i am not so sure.
 
-				ce->arg = (Expr *) node;
-				ce->collOid = attcollid;
-				ce->location = -1;
+				if (att->attgenerated == 'v')
+				{
+					virtual_node = build_column_default(rt_entry_relation, att->attnum);
+					if (virtual_node == NULL)
+						elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+							attnum, RelationGetRelationName(rt_entry_relation));
 
-				node = (Node *) ce;
-			}
+					attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, att->attnum, 0, 0);
+					if (attcollid && attcollid != exprCollation(node))
+					{
+						CollateExpr *ce = makeNode(CollateExpr);
 
-			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
-			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+						ce->arg = (Expr *) node;
+						ce->collOid = attcollid;
+						ce->location = -1;
+						virtual_node = (Node *) ce;
+					}
+
+					IncrementVarSublevelsUp(virtual_node, v->varlevelsup, 0);
+					ChangeVarNodes(virtual_node, 1, v->varno, v->varlevelsup);
+					fields = lappend(fields, virtual_node);
+				}
+				else
+				{
+					Var	*var = makeVar(v->varno,
+										att->attnum,
+										att->atttypid,
+										att->atttypmod,
+										att->attcollation,
+										v->varlevelsup);
+					fields = lappend(fields, var);
+				}
+			}
 
+			rowexpr = makeNode(RowExpr);
+			rowexpr->args = fields;
+			rowexpr->row_typeid = v->vartype;;
+			rowexpr->row_format = COERCE_IMPLICIT_CAST;
+			rowexpr->colnames = NIL;
+			rowexpr->location = -1;
 			table_close(rt_entry_relation, NoLock);
+			node = (Node *) rowexpr;
+			return node;
 		}
 
+
+		forboth(lc, context->virtual_gen_rel, lc2, context->virtual_attnums)
+		{
+			Oid	 virtual_rel = lfirst_oid(lc);
+			AttrNumber	attno = lfirst_int(lc2);
+
+			if(attno == attnum && virtual_rel == relid)
+			{
+				Relation	rt_entry_relation = table_open(relid, NoLock);
+
+				Assert(get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL);
+
+				node = build_column_default(rt_entry_relation, attnum);
+				if (node == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						attnum, RelationGetRelationName(rt_entry_relation));
+
+				/*
+				* If the column definition has a collation and it is different
+				* from the collation of the generation expression, put a COLLATE
+				* clause around the expression.
+				*/
+				attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+				if (attcollid && attcollid != exprCollation(node))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) node;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					node = (Node *) ce;
+				}
+
+				IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+				ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+				table_close(rt_entry_relation, NoLock);
+			}
+		}
 		return node;
 	}
 	else if (IsA(node, Query))
@@ -4457,6 +4540,7 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 
 	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
+		int	i;
 		RangeTblEntry *rte;
 		List	   *rtable;
 		struct expand_generated_context context;
@@ -4470,6 +4554,23 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 		rte->relid = RelationGetRelid(rel);
 		rtable = list_make2(rte, rte);
 		context.rtables = list_make1(rtable);
+		context.virtual_gen_rel = NIL;
+		context.virtual_attnums = NIL;
+
+		for (i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+			if (att->attisdropped)
+				continue;
+
+			if (att->attgenerated == 'v')
+			{
+				context.virtual_gen_rel = lappend_oid(context.virtual_gen_rel, rte->relid);
+				context.virtual_attnums = lappend_int(context.virtual_attnums, att->attnum);
+			}
+		}
+		Assert(list_length(context.virtual_gen_rel) > 0);
+		Assert(list_length(context.virtual_gen_rel) == list_length(context.virtual_attnums));
 
 		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
 	}
@@ -4477,6 +4578,65 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 		return node;
 }
 
+
+/*
+ * In a Query tree, if some vars are referencing virtual generated column we may
+ * need expand to its original default expression, however searching var is
+ * virtual generated via pg_attribute is expensive. so we preliminary collect
+ * the relation and virtual attnums that are virtual generated columns.  later
+ * we ultile this in expand_generated_columns_mutator.
+*/
+static bool
+collect_all_virtual_reloid_walker(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, RangeTblEntry))
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) node;
+		Oid		relid = rte->relid;
+
+		if (OidIsValid(relid))
+		{
+			int	i;
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			TupleDesc	tupdesc = RelationGetDescr(rt_entry_relation);
+
+			if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+			{
+				for (i = 0; i < tupdesc->natts; i++)
+				{
+					Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+					if (att->attisdropped)
+						continue;
+					if (att->attgenerated == 'v')
+					{
+						context->virtual_gen_rel = lappend_oid(context->virtual_gen_rel, relid);
+						context->virtual_attnums = lappend_int(context->virtual_attnums, att->attnum);
+					}
+				}
+				Assert(list_length(context->virtual_gen_rel) > 0);
+				Assert(list_length(context->virtual_gen_rel) == list_length(context->virtual_attnums));
+			}
+			table_close(rt_entry_relation, NoLock);
+			return false;
+		}
+		return false;			/* allow range_table_walker to continue */
+	}
+
+	if (IsA(node, Query))
+	{
+		return query_tree_walker((Query *) node,
+								  collect_all_virtual_reloid_walker,
+								  (void *) context,
+								  QTW_EXAMINE_RTES_AFTER);
+	}
+
+	return expression_tree_walker(node, collect_all_virtual_reloid_walker,
+								  (void *) context);
+}
+
 /*
  * Expand virtual generated columns in a Query.  We do some optimizations here
  * to avoid digging through the whole Query unless necessary.
@@ -4505,22 +4665,14 @@ expand_generated_columns_in_query(Query *query, struct expand_generated_context
 	 */
 	else
 	{
-		ListCell   *lc;
-
-		foreach(lc, query->rtable)
+		foreach_node(RangeTblEntry, rte, query->rtable)
 		{
-			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
-
 			if (rte->rtekind == RTE_SUBQUERY)
 				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
 		}
 
-		foreach(lc, query->cteList)
-		{
-			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
-
+		foreach_node(CommonTableExpr, cte, query->cteList)
 			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
-		}
 	}
 
 	if (query->hasGeneratedVirtual)
@@ -4579,6 +4731,11 @@ QueryRewrite(Query *parsetree)
 
 		query = fireRIRrules(query, NIL);
 
+		query_or_expression_tree_walker((Node *) query,
+										collect_all_virtual_reloid_walker,
+										(void *) &context,
+										QTW_EXAMINE_RTES_AFTER);
+
 		query = expand_generated_columns_in_query(query, &context);
 
 		query->queryId = input_query_id;
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 4cf4f8118f..67e9ffeec3 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -33,6 +33,37 @@ SELECT table_name, column_name, dependent_column FROM information_schema.column_
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
+--test with wholerow and ROW expr, some invidiual virtual generated should expanded.
+insert into gtest1 values (11, default) returning (select (select gtest1));
+ gtest1  
+---------
+ (11,22)
+(1 row)
+
+select gtest1 from gtest1 except all select gtest1 from gtest1;
+ gtest1 
+--------
+(0 rows)
+
+select row(gtest1.b) from gtest1;
+ row  
+------
+ (22)
+(1 row)
+
+select row(gtest1) from gtest1;
+     row     
+-------------
+ ("(11,22)")
+(1 row)
+
+with cte as (select (select gtest1) from gtest1) select cte from cte;
+     cte     
+-------------
+ ("(11,22)")
+(1 row)
+
+truncate gtest1;
 -- duplicate generated
 CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34b8070b3e..cd5a2eec3d 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -15,6 +15,13 @@ SELECT table_name, column_name, dependent_column FROM information_schema.column_
 
 \d gtest1
 
+--test with wholerow and ROW expr, some invidiual virtual generated should expanded.
+insert into gtest1 values (11, default) returning (select (select gtest1));
+select gtest1 from gtest1 except all select gtest1 from gtest1;
+select row(gtest1.b) from gtest1;
+select row(gtest1) from gtest1;
+with cte as (select (select gtest1) from gtest1) select cte from cte;
+truncate gtest1;
 -- duplicate generated
 CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
-- 
2.34.1

From 9eabb5d196f63edd934bb9b7be0c246abbea260a Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 29 Aug 2024 11:49:48 +0200
Subject: [PATCH v6 1/2] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 124 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/analyze.c                  |   8 +
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_clause.c             |   4 +
 src/backend/parser/parse_merge.c              |   1 +
 src/backend/parser/parse_relation.c           |   9 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 171 +++-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   3 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/parser/parse_node.h               |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |  32 +-
 ...rated_stored.out => generated_virtual.out} | 871 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |  14 +-
 ...rated_stored.sql => generated_virtual.sql} | 336 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 58 files changed, 1391 insertions(+), 710 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (69%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 80ddb45a60a..7e0b09e279b 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 5bff568d3b5..186dda1e8d0 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f3eb055e2c7..926c1fddbe3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 0734716ad90..058d53364db 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index b654fae1b2f..579b1d61660 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index b671858627b..378ae934baa 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 1a49f321cf7..c5aaf765446 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -264,6 +264,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -276,10 +281,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f21..ee79867d969 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2380,9 +2384,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 31626536a2e..5953d24ae8f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1c6da286d43..0c95a11f044 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2048,6 +2048,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 01b43cc6a84..29358f37307 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 902eb1a4508..f79ff40c3ec 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1030,6 +1030,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c5a56c75f69..ec4e8bc3902 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1085,6 +1085,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1094,14 +1097,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1114,6 +1125,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index b3cc6f8f690..0914e0566b0 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2936,6 +2936,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3207,6 +3216,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -5986,7 +6004,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7704,6 +7722,14 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
@@ -8301,7 +8327,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8458,17 +8495,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8611,6 +8661,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9690,6 +9750,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11671,7 +11744,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12722,8 +12795,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -12796,11 +12873,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -15758,6 +15836,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -17884,8 +17970,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -17967,9 +18056,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 170360edda8..021328746a1 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -942,6 +945,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2502,6 +2512,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3059,6 +3071,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3489,6 +3503,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6596,3 +6611,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index a6c47f61e0d..0baad880431 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2119,6 +2119,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 29e186fa73d..a49b1e821e0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1743,6 +1743,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2290,7 +2291,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e901203424d..e3936a0b8ea 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,6 +568,7 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -994,6 +995,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1459,6 +1461,7 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1685,6 +1688,7 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1936,6 +1940,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2410,6 +2415,7 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2477,6 +2483,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2843,6 +2850,7 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 84cef57a707..18ce875c406 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -640,7 +640,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -788,7 +788,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3973,7 +3973,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3981,6 +3981,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4027,6 +4028,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17809,6 +17816,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18462,6 +18470,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 8118036495b..48524ac3fc2 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,6 +207,10 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
+	if (pstate->p_target_relation->rd_att->constr &&
+		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 87df79027d7..350e9e18885 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,6 +405,7 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
+	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 2f64eaf0e37..b864749f09c 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
@@ -1511,6 +1515,9 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
+	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
+		pstate->p_hasGeneratedVirtual = true;
+
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 79cad4ab30c..03301f9c53e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -751,7 +751,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -839,6 +839,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 00e7024563e..cb2e864ad45 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 6d59a2bb8dc..f2713eaef23 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -44,6 +44,7 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
+#include "utils/syscache.h"
 
 
 /* We use a list of these to detect recursion in RewriteQuery */
@@ -90,6 +91,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+struct expand_generated_context;
+static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
 
 
 /*
@@ -974,7 +977,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -4365,6 +4369,168 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Virtual generated columns support
+ */
+
+struct expand_generated_context
+{
+	/* list of range tables, innermost last */
+	List	   *rtables;
+
+	/* incremented for every level where it's true */
+	int			ancestor_has_virtual;
+};
+
+static Node *
+expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+
+	if (IsA(node, Var))
+	{
+		Var		   *v = (Var *) node;
+		Oid			relid;
+		AttrNumber	attnum;
+		List	   *rtable = list_nth_node(List,
+										   context->rtables,
+										   list_length(context->rtables) - v->varlevelsup - 1);
+
+		relid = rt_fetch(v->varno, rtable)->relid;
+		attnum = v->varattno;
+
+		if (!relid || !attnum)
+			return node;
+
+		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Relation	rt_entry_relation = table_open(relid, NoLock);
+			Oid			attcollid;
+
+			node = build_column_default(rt_entry_relation, attnum);
+			if (node == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 attnum, RelationGetRelationName(rt_entry_relation));
+
+			/*
+			 * If the column definition has a collation and it is different
+			 * from the collation of the generation expression, put a COLLATE
+			 * clause around the expression.
+			 */
+			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
+			if (attcollid && attcollid != exprCollation(node))
+			{
+				CollateExpr *ce = makeNode(CollateExpr);
+
+				ce->arg = (Expr *) node;
+				ce->collOid = attcollid;
+				ce->location = -1;
+
+				node = (Node *) ce;
+			}
+
+			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
+			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+
+			table_close(rt_entry_relation, NoLock);
+		}
+
+		return node;
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *query = (Query *) node;
+
+		query = expand_generated_columns_in_query(query, context);
+
+		return (Node *) query;
+	}
+	else
+		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+		List	   *rtable;
+		struct expand_generated_context context;
+
+		/*
+		 * Make a dummy range table for a single relation.  For the benefit of
+		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
+		 * PRS2_NEW_VARNO.
+		 */
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		rtable = list_make2(rte, rte);
+		context.rtables = list_make1(rtable);
+
+		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
+	}
+	else
+		return node;
+}
+
+/*
+ * Expand virtual generated columns in a Query.  We do some optimizations here
+ * to avoid digging through the whole Query unless necessary.
+ */
+static Query *
+expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
+{
+	context->rtables = lappend(context->rtables, query->rtable);
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual++;
+
+	/*
+	 * If any table in the query has a virtual column or there is a sublink,
+	 * then we need to do the whole walk.
+	 */
+	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
+	{
+		query = query_tree_mutator(query,
+								   expand_generated_columns_mutator,
+								   context,
+								   QTW_DONT_COPY_QUERY);
+	}
+
+	/*
+	 * Else we only need to process subqueries.
+	 */
+	else
+	{
+		ListCell   *lc;
+
+		foreach(lc, query->rtable)
+		{
+			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+			if (rte->rtekind == RTE_SUBQUERY)
+				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
+		}
+
+		foreach(lc, query->cteList)
+		{
+			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
+		}
+	}
+
+	if (query->hasGeneratedVirtual)
+		context->ancestor_has_virtual--;
+	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
+
+	return query;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
@@ -4409,9 +4575,12 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
+		struct expand_generated_context context = {0};
 
 		query = fireRIRrules(query, NIL);
 
+		query = expand_generated_columns_in_query(query, &context);
+
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 63efc55f09e..dca8a5a4a21 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index dacb033e989..29662c5c19a 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -15994,6 +15994,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 5bcc2244d58..c3d6022015c 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3595,12 +3595,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 7c9a1f234c6..4309d3e757d 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index c512824cd1c..235ad73eedc 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 124d853e499..355f52199fa 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,6 +160,8 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
+	/* some table has a virtual generated column */
+	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
@@ -2730,6 +2732,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f8659078ced..6416f9b110b 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -489,6 +489,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 5b781d87a9d..1b02128548b 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,6 +225,7 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
+	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index d68ad7be345..9611aa82352 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3052,6 +3052,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 21b2b045933..cb715ad08b6 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 8ea8a3a92d2..8f0951e26a7 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -217,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -762,6 +783,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -1092,9 +1118,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 8ea8a3a92d2..4cf4f8118f3 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +211,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +288,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +311,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +327,42 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +375,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +413,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +435,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +500,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +509,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +524,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +539,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +552,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +560,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +593,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +738,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +756,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +793,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +801,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +908,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +963,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +971,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1033,20 +990,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1055,12 +1011,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1072,7 +1028,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1083,107 +1039,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1191,7 +1158,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1244,7 +1211,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1254,12 +1221,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1269,8 +1236,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1281,6 +1248,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1294,9 +1263,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1320,14 +1291,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1335,22 +1305,77 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 7a5a910562e..2e56537f194 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..36a6c2bddbe 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -390,6 +398,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 69%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..34b8070b3e3 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +142,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +173,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +234,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +249,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +260,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +433,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +445,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +476,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +498,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +512,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +524,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +551,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +560,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +633,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +689,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +697,47 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
+
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();

base-commit: a68159ff2b32f290b1136e2940470d50b8491301
-- 
2.46.0

From 7bfe4fc9ce81124d9e7fdc24a1f46099bcaec726 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 4 Sep 2024 09:38:42 +0200
Subject: [PATCH v6 2/2] Use ReplaceVarsFromTargetList() for rewriting virtual
 columns

---
 src/backend/parser/analyze.c         |   8 --
 src/backend/parser/parse_clause.c    |   4 -
 src/backend/parser/parse_merge.c     |   1 -
 src/backend/parser/parse_relation.c  |   3 -
 src/backend/rewrite/rewriteHandler.c | 185 ++++++++-------------------
 src/include/nodes/parsenodes.h       |   2 -
 src/include/parser/parse_node.h      |   1 -
 7 files changed, 54 insertions(+), 150 deletions(-)

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index e3936a0b8ea..e901203424d 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -568,7 +568,6 @@ transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -995,7 +994,6 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1461,7 +1459,6 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, stmt->lockingClause)
 	{
@@ -1688,7 +1685,6 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);
 
 	qry->hasSubLinks = pstate->p_hasSubLinks;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -1940,7 +1936,6 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, lockingClause)
 	{
@@ -2415,7 +2410,6 @@ transformReturnStmt(ParseState *pstate, ReturnStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2483,7 +2477,6 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
@@ -2850,7 +2843,6 @@ transformPLAssignStmt(ParseState *pstate, PLAssignStmt *stmt)
 	qry->hasWindowFuncs = pstate->p_hasWindowFuncs;
 	qry->hasTargetSRFs = pstate->p_hasTargetSRFs;
 	qry->hasAggs = pstate->p_hasAggs;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	foreach(l, sstmt->lockingClause)
 	{
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 48524ac3fc2..8118036495b 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -207,10 +207,6 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
 	pstate->p_target_relation = parserOpenTable(pstate, relation,
 												RowExclusiveLock);
 
-	if (pstate->p_target_relation->rd_att->constr &&
-		pstate->p_target_relation->rd_att->constr->has_generated_virtual)
-		pstate->p_hasGeneratedVirtual = true;
-
 	/*
 	 * Now build an RTE and a ParseNamespaceItem.
 	 */
diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c
index 350e9e18885..87df79027d7 100644
--- a/src/backend/parser/parse_merge.c
+++ b/src/backend/parser/parse_merge.c
@@ -405,7 +405,6 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt)
 
 	qry->hasTargetSRFs = false;
 	qry->hasSubLinks = pstate->p_hasSubLinks;
-	qry->hasGeneratedVirtual = pstate->p_hasGeneratedVirtual;
 
 	assign_query_collations(pstate, qry);
 
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b864749f09c..7a3199ae1d3 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -1515,9 +1515,6 @@ addRangeTableEntry(ParseState *pstate,
 	rte->eref = makeAlias(refname, NIL);
 	buildRelationAliases(rel->rd_att, alias, rte->eref);
 
-	if (rel->rd_att->constr && rel->rd_att->constr->has_generated_virtual)
-		pstate->p_hasGeneratedVirtual = true;
-
 	/*
 	 * Set flags and initialize access permissions.
 	 *
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index f2713eaef23..0241d471571 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -44,7 +44,6 @@
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
-#include "utils/syscache.h"
 
 
 /* We use a list of these to detect recursion in RewriteQuery */
@@ -91,8 +90,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
-struct expand_generated_context;
-static Query *expand_generated_columns_in_query(Query *query, struct expand_generated_context *context);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -2139,6 +2137,9 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 			}
 		}
 
+		/* Expand virtual generated columns of this table */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree, rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4370,84 +4371,66 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 
 
 /*
- * Virtual generated columns support
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
  */
-
-struct expand_generated_context
-{
-	/* list of range tables, innermost last */
-	List	   *rtables;
-
-	/* incremented for every level where it's true */
-	int			ancestor_has_virtual;
-};
-
 static Node *
-expand_generated_columns_mutator(Node *node, struct expand_generated_context *context)
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
 {
-	if (node == NULL)
-		return NULL;
+	TupleDesc	tupdesc;
 
-	if (IsA(node, Var))
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
-		Var		   *v = (Var *) node;
-		Oid			relid;
-		AttrNumber	attnum;
-		List	   *rtable = list_nth_node(List,
-										   context->rtables,
-										   list_length(context->rtables) - v->varlevelsup - 1);
-
-		relid = rt_fetch(v->varno, rtable)->relid;
-		attnum = v->varattno;
+		List	   *tlist = NIL;
 
-		if (!relid || !attnum)
-			return node;
-
-		if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+		for (int i = 0; i < tupdesc->natts; i++)
 		{
-			Relation	rt_entry_relation = table_open(relid, NoLock);
-			Oid			attcollid;
-
-			node = build_column_default(rt_entry_relation, attnum);
-			if (node == NULL)
-				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
-					 attnum, RelationGetRelationName(rt_entry_relation));
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
 
-			/*
-			 * If the column definition has a collation and it is different
-			 * from the collation of the generation expression, put a COLLATE
-			 * clause around the expression.
-			 */
-			attcollid = GetSysCacheOid(ATTNUM, Anum_pg_attribute_attcollation, relid, attnum, 0, 0);
-			if (attcollid && attcollid != exprCollation(node))
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			{
-				CollateExpr *ce = makeNode(CollateExpr);
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
 
-				ce->arg = (Expr *) node;
-				ce->collOid = attcollid;
-				ce->location = -1;
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
 
-				node = (Node *) ce;
-			}
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
 
-			IncrementVarSublevelsUp(node, v->varlevelsup, 0);
-			ChangeVarNodes(node, 1, v->varno, v->varlevelsup);
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
 
-			table_close(rt_entry_relation, NoLock);
-		}
+					defexpr = (Node *) ce;
+				}
 
-		return node;
-	}
-	else if (IsA(node, Query))
-	{
-		Query	   *query = (Query *) node;
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
 
-		query = expand_generated_columns_in_query(query, context);
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
 
-		return (Node *) query;
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
 	}
-	else
-		return expression_tree_mutator(node, expand_generated_columns_mutator, context);
+
+	return node;
 }
 
 Node *
@@ -4458,76 +4441,19 @@ expand_generated_columns_in_expr(Node *node, Relation rel)
 	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
 		RangeTblEntry *rte;
-		List	   *rtable;
-		struct expand_generated_context context;
 
-		/*
-		 * Make a dummy range table for a single relation.  For the benefit of
-		 * triggers, add the same entry twice, so it covers PRS2_OLD_VARNO and
-		 * PRS2_NEW_VARNO.
-		 */
 		rte = makeNode(RangeTblEntry);
 		rte->relid = RelationGetRelid(rel);
-		rtable = list_make2(rte, rte);
-		context.rtables = list_make1(rtable);
-
-		return expression_tree_mutator(node, expand_generated_columns_mutator, &context);
-	}
-	else
-		return node;
-}
-
-/*
- * Expand virtual generated columns in a Query.  We do some optimizations here
- * to avoid digging through the whole Query unless necessary.
- */
-static Query *
-expand_generated_columns_in_query(Query *query, struct expand_generated_context *context)
-{
-	context->rtables = lappend(context->rtables, query->rtable);
-	if (query->hasGeneratedVirtual)
-		context->ancestor_has_virtual++;
-
-	/*
-	 * If any table in the query has a virtual column or there is a sublink,
-	 * then we need to do the whole walk.
-	 */
-	if (query->hasGeneratedVirtual || query->hasSubLinks || context->ancestor_has_virtual)
-	{
-		query = query_tree_mutator(query,
-								   expand_generated_columns_mutator,
-								   context,
-								   QTW_DONT_COPY_QUERY);
-	}
-
-	/*
-	 * Else we only need to process subqueries.
-	 */
-	else
-	{
-		ListCell   *lc;
-
-		foreach(lc, query->rtable)
-		{
-			RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
-
-			if (rte->rtekind == RTE_SUBQUERY)
-				rte->subquery = expand_generated_columns_in_query(rte->subquery, context);
-		}
 
-		foreach(lc, query->cteList)
-		{
-			CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
-
-			cte->ctequery = (Node *) expand_generated_columns_in_query(castNode(Query, cte->ctequery), context);
-		}
+		/*
+		 * XXX For the benefit of triggers, make two passes, so it covers
+		 * PRS2_OLD_VARNO and PRS2_NEW_VARNO.
+		 */
+		node = expand_generated_columns_internal(node, rel, 1, rte);
+		node = expand_generated_columns_internal(node, rel, 2, rte);
 	}
 
-	if (query->hasGeneratedVirtual)
-		context->ancestor_has_virtual--;
-	context->rtables = list_truncate(context->rtables, list_length(context->rtables) - 1);
-
-	return query;
+	return node;
 }
 
 
@@ -4575,12 +4501,9 @@ QueryRewrite(Query *parsetree)
 	foreach(l, querylist)
 	{
 		Query	   *query = (Query *) lfirst(l);
-		struct expand_generated_context context = {0};
 
 		query = fireRIRrules(query, NIL);
 
-		query = expand_generated_columns_in_query(query, &context);
-
 		query->queryId = input_query_id;
 
 		results = lappend(results, query);
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 355f52199fa..0e91c084a01 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -160,8 +160,6 @@ typedef struct Query
 	bool		hasForUpdate pg_node_attr(query_jumble_ignore);
 	/* rewriter has applied some RLS policy */
 	bool		hasRowSecurity pg_node_attr(query_jumble_ignore);
-	/* some table has a virtual generated column */
-	bool		hasGeneratedVirtual pg_node_attr(query_jumble_ignore);
 	/* is a RETURN statement */
 	bool		isReturn pg_node_attr(query_jumble_ignore);
 
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 1b02128548b..5b781d87a9d 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -225,7 +225,6 @@ struct ParseState
 	bool		p_hasTargetSRFs;
 	bool		p_hasSubLinks;
 	bool		p_hasModifyingCTE;
-	bool		p_hasGeneratedVirtual;
 
 	Node	   *p_last_srf;		/* most recent set-returning func/op found */
 
-- 
2.46.0

From 7a79374caa8196d6bba908c7a83ebe4ef7e66f53 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 16 Sep 2024 16:58:55 +0800
Subject: [PATCH v7 1/1] Virtual generated columns no table_rewrite

minor change RelationBuildTupleDesc.
if constr->has_generated_virtual is true
assign constr to relation->rd_att->constr.

make virtual generated columns no table_rewrite.
add tests on src/test/regress/sql/fast_default.sql
---
 src/backend/commands/tablecmds.c           |  2 +-
 src/backend/utils/cache/relcache.c         |  1 +
 src/test/regress/expected/fast_default.out | 12 ++++++++++++
 src/test/regress/sql/fast_default.sql      | 10 ++++++++++
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0914e0566b..b01e431355 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -7181,7 +7181,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index dca8a5a4a2..c8a711cb7e 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -687,6 +687,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad96..0c77fdada8 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+--virtual generated column don't need rewrite.
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+--here, we do need rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+--stored generated column need rewrite.
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35..ed860c1e45 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -65,8 +65,18 @@ ALTER TABLE has_volatile ADD col1 int;
 ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
+--virtual generated column don't need rewrite.
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
 
+--here, we do need rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
 
+--stored generated column need rewrite.
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
 
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);

base-commit: 4632e5cf4bc5c496f41dfc6a89533e7afa7262dd
prerequisite-patch-id: 3d7cd74ab7d10140274b25350d8e27e73db99210
-- 
2.34.1

From 96c6dddfbee75200321ad6a7d0eee6c49a544f74 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Wed, 18 Sep 2024 10:29:46 +0800
Subject: [PATCH v6 1/1] virtual generated columns misc changes.

* change tests on contrib/pageinspect/sql/page.sql
* also change relcache.c make cached constr->has_not_null,
constr->has_generated_stored, constr->has_generated_virtual more accurate.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         | 20 +++++++++++--------
 contrib/pageinspect/sql/page.sql              |  8 ++++++--
 src/backend/commands/tablecmds.c              |  2 +-
 src/backend/utils/cache/relcache.c            | 12 +++++++++--
 .../regress/expected/generated_virtual.out    |  4 ++--
 5 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index bacd371a9d..02b1bbb1ab 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -212,10 +212,12 @@ drop table test8;
 -- stored
 create table test9s (a int not null, b int generated always as (a * 2) stored);
 insert into test9s values (131584);
-select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
- t_infomask | t_bits |       t_data       
-------------+--------+--------------------
-       2048 |        | \x0002020000040400
+select sub.raw_flags as t_infomask_info, t_bits is null as expect_true, t_data 
+from heap_page_items(get_raw_page('test9s', 0)),
+     heap_tuple_infomask_flags(t_infomask, 0) sub;
+   t_infomask_info   | expect_true |       t_data       
+---------------------+-------------+--------------------
+ {HEAP_XMAX_INVALID} | t           | \x0002020000040400
 (1 row)
 
 select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
@@ -229,10 +231,12 @@ drop table test9s;
 -- virtual
 create table test9v (a int not null, b int generated always as (a * 2) virtual);
 insert into test9v values (131584);
-select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
- t_infomask |  t_bits  |   t_data   
-------------+----------+------------
-       2049 | 10000000 | \x00020200
+select sub.raw_flags as t_infomask_info, t_bits is not null as expect_true, t_data 
+from heap_page_items(get_raw_page('test9v', 0)),
+     heap_tuple_infomask_flags(t_infomask, 0) sub;
+         t_infomask_info          | expect_true |   t_data   
+----------------------------------+-------------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | t           | \x00020200
 (1 row)
 
 select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 923687d063..81866db25a 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -88,7 +88,9 @@ drop table test8;
 -- stored
 create table test9s (a int not null, b int generated always as (a * 2) stored);
 insert into test9s values (131584);
-select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select sub.raw_flags as t_infomask_info, t_bits is null as expect_true, t_data
+from heap_page_items(get_raw_page('test9s', 0)),
+     heap_tuple_infomask_flags(t_infomask, 0) sub;
 select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
     from heap_page_items(get_raw_page('test9s', 0));
 drop table test9s;
@@ -96,7 +98,9 @@ drop table test9s;
 -- virtual
 create table test9v (a int not null, b int generated always as (a * 2) virtual);
 insert into test9v values (131584);
-select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select sub.raw_flags as t_infomask_info, t_bits is not null as expect_true, t_data
+from heap_page_items(get_raw_page('test9v', 0)),
+     heap_tuple_infomask_flags(t_infomask, 0) sub;
 select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
     from heap_page_items(get_raw_page('test9v', 0));
 drop table test9v;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index b01e431355..03f9376d8b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9731,7 +9731,7 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	{
 		char		attgenerated = TupleDescAttr(RelationGetDescr(rel), fkattnum[i] - 1)->attgenerated;
 
-		if (attgenerated)
+		if (attgenerated == ATTRIBUTE_GENERATED_STORED)
 		{
 			/*
 			 * Check restrictions on UPDATE/DELETE actions, per SQL standard
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index c8a711cb7e..a421ee6d38 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -3541,6 +3541,8 @@ RelationBuildLocalRelation(const char *relname,
 	int			natts = tupDesc->natts;
 	int			i;
 	bool		has_not_null;
+	bool		has_generated_stored;
+	bool		has_generated_virtual;
 	bool		nailit;
 
 	Assert(natts >= 0);
@@ -3617,6 +3619,8 @@ RelationBuildLocalRelation(const char *relname,
 	rel->rd_att = CreateTupleDescCopy(tupDesc);
 	rel->rd_att->tdrefcount = 1;	/* mark as refcounted */
 	has_not_null = false;
+	has_generated_stored = false;
+	has_generated_virtual = false;
 	for (i = 0; i < natts; i++)
 	{
 		Form_pg_attribute satt = TupleDescAttr(tupDesc, i);
@@ -3626,13 +3630,17 @@ RelationBuildLocalRelation(const char *relname,
 		datt->attgenerated = satt->attgenerated;
 		datt->attnotnull = satt->attnotnull;
 		has_not_null |= satt->attnotnull;
+		has_generated_stored |= (satt->attgenerated == ATTRIBUTE_GENERATED_STORED);
+		has_generated_virtual |= (satt->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL);
 	}
 
-	if (has_not_null)
+	if (has_not_null || has_generated_stored || has_generated_virtual)
 	{
 		TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
 
-		constr->has_not_null = true;
+		constr->has_not_null = has_not_null;
+		constr->has_generated_stored = has_generated_stored;
+		constr->has_generated_virtual = has_generated_virtual;
 		rel->rd_att->constr = constr;
 	}
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 4cf4f8118f..c32ef7f787 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -678,9 +678,9 @@ CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
 --INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
+ERROR:  foreign key constraints on virtual generated columns are not supported
 CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
-ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
+ERROR:  foreign key constraints on virtual generated columns are not supported
 CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
 ERROR:  foreign key constraints on virtual generated columns are not supported
 --\d gtest23b
-- 
2.34.1

From 53499561979cd7af71635194eb86e686643c9f9a Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Sun, 29 Sep 2024 21:55:05 -0400
Subject: [PATCH v7] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control
- check FDW/foreign table behavior

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  35 +
 contrib/pageinspect/sql/page.sql              |  17 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  14 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 122 ++-
 src/backend/commands/trigger.c                |  49 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 111 ++-
 src/backend/utils/cache/partcache.c           |   2 +
 src/backend/utils/cache/relcache.c            |   2 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/create_table_like.out    |  23 +-
 .../regress/expected/generated_stored.out     |  32 +-
 ...rated_stored.out => generated_virtual.out} | 871 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/generated_stored.sql     |  14 +-
 ...rated_stored.sql => generated_virtual.sql} | 336 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 54 files changed, 1311 insertions(+), 709 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (69%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..bacd371a9d5 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,41 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+ t_infomask | t_bits |       t_data       
+------------+--------+--------------------
+       2048 |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+ t_infomask |  t_bits  |   t_data   
+------------+----------+------------
+       2049 | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..923687d0630 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,23 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9s', 0));
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select t_infomask, t_bits, t_data from heap_page_items(get_raw_page('test9v', 0));
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f2bcd6aa98c..614e8135e0e 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 372fe6dad15..32e16bfc0e2 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index bfb97865e18..64d0fc61f62 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 8ab0ddb112f..4591be60488 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 1a49f321cf7..c5aaf765446 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -264,6 +264,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -276,10 +281,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index c1855b8d827..1f7ccbca830 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -720,8 +720,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -897,7 +898,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -906,8 +907,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2447,9 +2451,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 49382d07fa8..dab17f7ae4f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 1c6da286d43..0c95a11f044 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2048,6 +2048,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 78e59384d1c..287f03853ad 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 38fb4c3ef23..713ca5e8661 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1039,6 +1039,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 130cebd6588..ed2377aeed2 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1104,6 +1104,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1113,14 +1116,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1133,6 +1144,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7405023e77b..f67d435e5dc 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2943,6 +2943,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3214,6 +3223,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6040,7 +6058,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7761,6 +7779,14 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
@@ -8358,7 +8384,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8515,17 +8552,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8668,6 +8718,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9778,6 +9838,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12924,8 +12997,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -12998,11 +13075,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -15963,6 +16041,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18096,8 +18182,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18179,9 +18268,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 3671e82535e..7602b271256 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -943,6 +946,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2503,6 +2513,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3060,6 +3072,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3490,6 +3504,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6600,3 +6616,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 9fd988cc992..62d453687f2 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2119,6 +2119,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 728cdee480b..a1c0dcab059 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1761,6 +1761,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2308,7 +2309,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index b1d4642c59b..81d7b1161de 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -641,7 +641,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -789,7 +789,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3974,7 +3974,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3982,6 +3982,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4028,6 +4029,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17845,6 +17852,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18499,6 +18507,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 8075b1b8a1b..6f8f96b34da 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 1e15ce10b48..4707139a91f 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -779,7 +779,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -867,6 +867,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 00e7024563e..60acfb587cf 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -996,7 +997,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 6d59a2bb8dc..0829c3b49db 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -90,6 +90,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -974,7 +975,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2257,6 +2259,30 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		table_close(rel, NoLock);
 	}
 
+	/*
+	 * Expand virtual generated columns of this table
+	 *
+	 * This must be last, since whatever else gets inserted into the query
+	 * above could contain a generated column.
+	 */
+	rt_index = 0;
+	foreach(lc, parsetree->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+
+		++rt_index;
+
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree, rel, rt_index, rte);
+
+		table_close(rel, NoLock);
+	}
+
 	return parsetree;
 }
 
@@ -4365,6 +4391,89 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..20f607bc330 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -157,6 +158,7 @@ RelationBuildPartitionKey(Relation relation)
 		 * in canonical form already (ie, no need for OR-merging or constant
 		 * elimination).
 		 */
+		expr = expand_generated_columns_in_expr(expr, relation, 1);
 		expr = eval_const_expressions(NULL, expr);
 		fix_opfuncids(expr);
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index c326f687eb4..9c2c47d9cf3 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -589,6 +589,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 130b80775db..3b9944ac6db 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16007,6 +16007,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index ab6c8304913..2b7599d3263 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3631,12 +3631,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 6a36c910833..824792075c5 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2089,6 +2089,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index c512824cd1c..235ad73eedc 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index e62ce1b7536..8e9c9980e81 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2739,6 +2739,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	int			inhcount;		/* initial inheritance count to apply, for
 								 * "raw" NOT NULL constraints */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 899d64ad55f..efe25d7de0f 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -490,6 +490,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..8ec879193e2 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index fe719935c67..4cb5969c589 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3048,6 +3048,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index e2ccaa84f3f..bc45412daab 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3203,6 +3203,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 8ea8a3a92d2..8f0951e26a7 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -217,6 +217,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -762,6 +783,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -1092,9 +1118,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 8ea8a3a92d2..4cf4f8118f3 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,15 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +18,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -153,16 +153,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +197,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +211,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +288,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +311,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +327,42 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +375,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +413,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +435,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +500,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +509,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +524,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +539,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +552,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +560,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +593,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +738,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,33 +756,33 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,7 +793,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
@@ -850,95 +801,101 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +908,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +963,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +971,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1033,20 +990,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1055,12 +1011,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1072,7 +1028,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1083,107 +1039,118 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -1191,7 +1158,7 @@ ERROR:  cannot drop generation expression from inherited column
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1244,7 +1211,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1254,12 +1221,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1269,8 +1236,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1281,6 +1248,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1294,9 +1263,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1320,14 +1291,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1335,22 +1305,77 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
+-- TODO: extra tests to weave into the right places
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+ a  | b  | d  | b  
+----+----+----+----
+  1 |  2 | 22 |  2
+  2 |  4 | 22 |  4
+  3 |  6 | 22 |  6
+  4 |  8 | 22 |  8
+  5 | 10 | 22 | 10
+  6 | 12 | 22 | 12
+  7 | 14 | 22 | 14
+  8 | 16 | 22 | 16
+  9 | 18 | 22 | 18
+ 10 | 20 | 22 | 20
+(10 rows)
+
+DROP TABLE t2;
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "at_tab1" because column "at_tab2.y" uses its row type
+DROP TABLE at_tab1, at_tab2;
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 4f38104ba01..b90f48b11d8 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..36a6c2bddbe 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,5 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -390,6 +398,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 69%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..34b8070b3e3 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,55 @@
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -70,7 +70,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +93,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +103,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +142,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +173,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +234,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +249,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +260,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +433,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,7 +445,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
-CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,21 +476,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +498,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +512,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +524,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +551,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +560,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -552,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +633,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +689,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +697,47 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- TODO: extra tests to weave into the right places
+
+-- sublinks
+CREATE TABLE t2 (
+    a int,
+    b int GENERATED ALWAYS AS (a * 2),
+    d int DEFAULT 22
+);
+INSERT INTO t2 (a) SELECT g FROM generate_series(1, 10) g;
+SELECT a, b, d, (SELECT t2.b) FROM t2;
+DROP TABLE t2;
+
+-- collate
+/*
+CREATE COLLATION case_insensitive (provider = icu, locale = 'und-u-ks-level2', deterministic = false);
+CREATE TABLE t5 (
+    a text collate "C",
+    b text collate "C" GENERATED ALWAYS AS (a collate case_insensitive) ,
+    d int DEFAULT 22
+);
+INSERT INTO t5 (a, d) values ('d1', 28), ('D2', 27), ('D1', 26);
+SELECT * FROM t5 ORDER BY b ASC, d ASC;
+DROP TABLE t5;
+DROP COLLATION case_insensitive;
+*/
+
+-- composite type dependencies
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE at_tab1 (a int, b text GENERATED ALWAYS AS ('hello'), c text) PARTITION BY LIST (a);
+CREATE TABLE at_tab2 (x int, y at_tab1);
+ALTER TABLE at_tab1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE at_tab1, at_tab2;
+
+-- attach mixing generated kinds
+CREATE TABLE bar1 (a integer, b integer GENERATED ALWAYS AS (22)) PARTITION BY RANGE (a);
+CREATE TABLE bar2 (a integer, b integer GENERATED ALWAYS AS (22) STORED);
+ALTER TABLE bar1 ATTACH PARTITION bar2 DEFAULT;  -- error
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();

base-commit: 6fd5071909a2886c499871e61127f815fd9bb6a2
-- 
2.46.2

From 842faee2964679e183b164f3bf9f418ba4ae460e Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 5 Nov 2024 16:48:42 +0100
Subject: [PATCH v8] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control

contributions by Jian He, Dean Rasheed

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  16 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 126 ++-
 src/backend/commands/trigger.c                |  48 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 102 +-
 src/backend/utils/cache/partcache.c           |   3 +
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     |  77 +-
 ...rated_stored.out => generated_virtual.out} | 868 +++++++++---------
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/collate.icu.utf8.sql     |  14 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  38 +-
 ...rated_stored.sql => generated_virtual.sql} | 313 ++++---
 src/test/subscription/t/011_generated.pl      |  38 +-
 58 files changed, 1412 insertions(+), 710 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (69%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f2bcd6aa98c..614e8135e0e 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 372fe6dad15..32e16bfc0e2 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 964c819a02d..8c2b5038132 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index f02f67d7b86..2d7c516d569 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 36770c012a6..c55ab25e06a 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -266,6 +266,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -278,10 +283,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index dc4b9075990..21b5d6a14d0 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -275,7 +275,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -284,10 +284,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 83859bac76f..509624b250c 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -724,8 +724,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -901,7 +902,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -910,8 +911,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2451,9 +2455,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index a9abaab9056..46c6c2f126f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a8d95e0f1c1..ecc3f599b41 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index c54a543c536..7a954cf6cc3 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 9a56de2282f..ba7b28523d9 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 2f652463e3c..4e4882a3bd3 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1104,6 +1104,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1113,14 +1116,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1133,6 +1144,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4345b96de5e..22591c233e9 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -2966,6 +2966,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3237,6 +3246,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6061,7 +6079,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7241,7 +7259,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7760,6 +7778,14 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/*
 	 * Okay, actually perform the catalog change ... if needed
 	 */
@@ -8357,7 +8383,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8514,17 +8551,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8667,6 +8717,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9777,6 +9837,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -11933,7 +12006,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -12994,8 +13067,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13068,11 +13145,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16033,6 +16111,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18167,8 +18253,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18250,9 +18339,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 09356e46d16..2228d1a3bce 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -943,6 +946,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2503,6 +2513,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3060,6 +3072,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3490,6 +3504,7 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6600,3 +6615,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 30c5a19aad6..1c50197ae72 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2121,6 +2121,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index cc9a594cba5..5f0d09ab703 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1752,6 +1752,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2299,7 +2300,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 89fdb94c237..65688ffd363 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -628,7 +628,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -776,7 +776,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3982,7 +3982,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3990,6 +3990,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4036,6 +4037,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17904,6 +17911,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18558,6 +18566,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 8075b1b8a1b..6f8f96b34da 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 1e15ce10b48..4707139a91f 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -779,7 +779,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -867,6 +867,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 12c17359063..215c666af7a 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -992,7 +993,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 6d59a2bb8dc..ef86dedd9c0 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -90,6 +90,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -974,7 +975,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2135,6 +2137,15 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 			}
 		}
 
+		/*
+		 * Expand virtual generated columns of this table
+		 *
+		 * FIXME: This should be done after applying RLS policies below, since
+		 * those could also contain virtual columns.  But that currently makes
+		 * some tests fail, so it needs further investigation.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree, rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4365,6 +4376,95 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+
+		/*
+		 * XXX For the benefit of triggers, make two passes, so it covers
+		 * PRS2_OLD_VARNO and PRS2_NEW_VARNO.
+		 */
+		node = expand_generated_columns_internal(node, rel, 1, rte);
+		node = expand_generated_columns_internal(node, rel, 2, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c
index beec6cddbc4..1dee7c1e899 100644
--- a/src/backend/utils/cache/partcache.c
+++ b/src/backend/utils/cache/partcache.c
@@ -26,6 +26,7 @@
 #include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "partitioning/partbounds.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
@@ -148,6 +149,8 @@ RelationBuildPartitionKey(Relation relation)
 		expr = stringToNode(exprString);
 		pfree(exprString);
 
+		expr = expand_generated_columns_in_expr(expr, relation);
+
 		/*
 		 * Run the expressions through const-simplification since the planner
 		 * will be comparing them to similarly-processed qual clause operands,
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 5bbb654a5db..8d3b08475c3 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -590,6 +590,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -686,6 +688,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index d8c6330732e..25480e1b126 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16020,6 +16020,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index ac60829d686..f571a259b06 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3631,12 +3631,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 363a66e7185..d61c4ae7999 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2085,6 +2085,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index d6a2c791290..33b950ad6df 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 0d96db56386..15d898ef5dc 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2765,6 +2765,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 899d64ad55f..efe25d7de0f 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -490,6 +490,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..a646a20675a 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 80de0db40de..0de48148b47 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3202,6 +3202,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index faa376e060c..5a94ce13afa 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2054,6 +2054,26 @@ SELECT (SELECT count(*) FROM test33_0) <> (SELECT count(*) FROM test33_1);
  t
 (1 row)
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 6bfc6d040ff..97157dc635b 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 8ea8a3a92d2..766cb4fc0af 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,6 @@
+-- keep these tests aligned with generated_virtual.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -217,6 +236,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -312,6 +352,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -762,6 +806,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -792,6 +841,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -805,6 +859,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1092,9 +1151,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1188,6 +1247,18 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 8ea8a3a92d2..8864fe8bb18 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,16 @@
+-- keep these tests aligned with generated_stored.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +19,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -153,16 +172,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +216,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +230,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +307,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +330,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,23 +346,42 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -341,28 +394,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -379,8 +432,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -401,7 +454,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -466,7 +519,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -475,7 +528,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -490,7 +543,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -505,11 +558,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -518,7 +571,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -526,30 +579,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -558,231 +612,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -792,6 +757,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -806,32 +776,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -842,103 +817,127 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+  tableoid   |     f1     | f2 | f3 
+-------------+------------+----+----
+ gtest_child | 07-15-2016 |  1 |  2
+ gtest_child | 07-15-2016 |  2 |  4
+(2 rows)
+
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child2 | 08-15-2016 |  3 | 66
+(1 row)
+
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
+ tableoid | f1 | f2 | f3 
+----------+----+----+----
+(0 rows)
+
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -951,54 +950,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1006,7 +1005,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1014,12 +1013,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1033,20 +1032,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1055,12 +1053,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1072,7 +1070,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1083,115 +1081,138 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1244,7 +1265,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1254,12 +1275,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1269,8 +1290,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1281,6 +1302,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1294,9 +1317,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1320,14 +1345,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1335,22 +1359,22 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 81e4222d26a..782d7d11dcb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 80f28a97d78..57cc11a3eed 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -796,6 +796,20 @@ CREATE TABLE test33_1 PARTITION OF test33 FOR VALUES WITH (MODULUS 2, REMAINDER
 -- they end up in the same partition (but it's platform-dependent which one)
 SELECT (SELECT count(*) FROM test33_0) <> (SELECT count(*) FROM test33_1);
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
 
 -- cleanup
 RESET search_path;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 04008a027b8..ddf893f7ec3 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..02fa17386c4 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,8 @@
+-- keep these tests aligned with generated_virtual.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -142,6 +155,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 
@@ -390,6 +404,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
@@ -417,6 +435,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,6 +447,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -549,6 +573,18 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 69%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..cb727c44cfb 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,58 @@
+-- keep these tests aligned with generated_stored.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -70,7 +75,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +98,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +147,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +178,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +239,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +254,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +265,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +438,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -427,6 +451,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -435,6 +462,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
@@ -457,21 +487,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +509,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +523,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +535,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +562,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -549,10 +579,22 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +656,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +712,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 8b2e5f4708e..faee155daa7 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,12 +88,12 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 done_testing();

base-commit: 7d85d87f4d5c35fd5b2d38adaef63dfbfa542ccc
-- 
2.47.0

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
new file mode 100644
index ef86ded..33ef64c
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2137,15 +2137,6 @@ fireRIRrules(Query *parsetree, List *act
 			}
 		}
 
-		/*
-		 * Expand virtual generated columns of this table
-		 *
-		 * FIXME: This should be done after applying RLS policies below, since
-		 * those could also contain virtual columns.  But that currently makes
-		 * some tests fail, so it needs further investigation.
-		 */
-		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree, rel, rt_index, rte);
-
 		table_close(rel, NoLock);
 	}
 
@@ -2171,6 +2162,10 @@ fireRIRrules(Query *parsetree, List *act
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2184,10 +2179,11 @@ fireRIRrules(Query *parsetree, List *act
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2265,6 +2261,14 @@ fireRIRrules(Query *parsetree, List *act
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
+																rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
new file mode 100644
index 3191908..0f31602
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4378,6 +4378,35 @@ INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
 DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
+DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
new file mode 100644
index 3011d71..6e15a5e
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ INSERT INTO r1 VALUES (10)
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);

From 90ee6fb718961d651aede5da998bdeaddbb5cf09 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 12 Nov 2024 12:58:16 +0100
Subject: [PATCH v9] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

Some functionality is currently not supported (but could possibly be
added as incremental features, some easier than others):

- index on virtual column
- expression index using a virtual column
- hence also no unique constraints on virtual columns
- not-null constraints on virtual columns
- (check constraints are supported)
- foreign key constraints on virtual columns
- extended statistics on virtual columns
- ALTER TABLE / SET EXPRESSION
- ALTER TABLE / DROP EXPRESSION
- virtual columns as trigger columns
- virtual column cannot have domain type

TODO:
- analysis of access control

contributions by Jian He, Dean Rasheed

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   4 +-
 doc/src/sgml/ddl.sgml                         |  25 +-
 doc/src/sgml/ref/alter_table.sgml             |  16 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/ref/create_trigger.sgml          |   2 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  13 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  29 +-
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 126 ++-
 src/backend/commands/trigger.c                |  49 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  14 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 109 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     |  77 +-
 ...rated_stored.out => generated_virtual.out} | 868 +++++++++---------
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  38 +-
 ...rated_stored.sql => generated_virtual.sql} | 313 ++++---
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/subscription/t/011_generated.pl      |  38 +-
 59 files changed, 1470 insertions(+), 714 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (69%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f2bcd6aa98c..614e8135e0e 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 372fe6dad15..32e16bfc0e2 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index c180ed7abbc..b6ee20573e5 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,8 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 3c56610d2ac..3769afd92d9 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 6098ebed433..17aae68af43 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -267,6 +267,11 @@ <title>Description</title>
       in the column is rewritten and all the future changes will apply the new
       generation expression.
      </para>
+
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
     </listitem>
    </varlistentry>
 
@@ -279,10 +284,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index fc81ba3c498..7fe13e6e584 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -281,7 +281,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -290,10 +290,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index dd83b07d65f..47f72896d24 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2450,9 +2454,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 982ab6f3ee4..752fe50860a 100644
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -279,7 +279,7 @@ <title>Parameters</title>
      <para>
       <literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
       A column list cannot be specified when requesting transition relations,
-      either.
+      either.  Virtual generated columns are not supported in the column list.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index a9abaab9056..46c6c2f126f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a8d95e0f1c1..ecc3f599b41 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 003af4bf21c..b2ef8254235 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 9a56de2282f..ba7b28523d9 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index d1134733c17..25c1fbf972f 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1111,6 +1111,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1120,14 +1123,22 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("index creation on virtual generated columns is not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1140,6 +1151,22 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("index creation on virtual generated columns is not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index ccd9645e7d2..2907974eed3 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3020,6 +3020,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3292,6 +3301,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6093,7 +6111,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7271,7 +7289,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7748,6 +7766,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8396,7 +8422,18 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a different implementation:
+	 * no rewriting, but still need to recheck any constraints.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
@@ -8553,17 +8590,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8706,6 +8756,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9895,6 +9955,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12051,7 +12124,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -13233,8 +13306,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13307,11 +13384,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16297,6 +16375,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18526,8 +18612,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18609,9 +18698,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 09356e46d16..a9058370348 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -943,6 +946,13 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 						 errmsg("column \"%s\" of relation \"%s\" does not exist",
 								name, RelationGetRelationName(rel))));
 
+			/* Currently doesn't work. */
+			if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("virtual generated columns are not supported as trigger columns"),
+						errdetail("Column \"%s\" is a virtual generated column.", name));
+
 			/* Check for duplicates */
 			for (j = i - 1; j >= 0; j--)
 			{
@@ -2503,6 +2513,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3060,6 +3072,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3490,6 +3504,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6600,3 +6616,34 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			bool		isnull;
+
+			fastgetattr(tuple, i + 1, tupdesc, &isnull);
+			if (!isnull)
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 30c5a19aad6..1c50197ae72 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2121,6 +2121,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 5ca856fd279..e49acc20845 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1757,6 +1757,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2304,7 +2305,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 67eb96396af..242a18cf78d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -628,7 +628,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -776,7 +776,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3985,7 +3985,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3993,6 +3993,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4039,6 +4040,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17921,6 +17928,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18575,6 +18583,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 8075b1b8a1b..6f8f96b34da 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 0f324ee4e31..bcfab424c1e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -986,6 +986,18 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index a6002b223df..3d11d7c5918 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1000,7 +1001,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 063afd4933e..d59fe2e7ce8 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -980,7 +981,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2204,6 +2206,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2217,10 +2223,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2309,6 +2316,14 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
+																rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4420,6 +4435,90 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 342467fd186..60c477ec9f9 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -590,6 +590,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -686,6 +688,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index a8c141b689d..86cc1dd1339 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16182,6 +16182,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index aa1564cd450..8fc981d52e9 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3641,12 +3641,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 5bfebad64d5..e257863cde4 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2084,6 +2084,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 8c278f202b4..ec95d9ba7f1 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 0f9462493e3..07204b7bf62 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2765,6 +2765,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 899d64ad55f..efe25d7de0f 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -490,6 +490,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..8ec879193e2 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index 80de0db40de..0de48148b47 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3202,6 +3202,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 6fa32ae3649..37fb9afd7aa 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2378,6 +2378,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index d091da5a1ef..490ec986b35 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 0d037d48ca0..1095e945b7a 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,6 @@
+-- keep these tests aligned with generated_virtual.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -217,6 +236,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -312,6 +352,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -764,6 +808,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -794,6 +843,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -807,6 +861,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1094,9 +1153,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1190,6 +1249,18 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 0d037d48ca0..b66eba63db8 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,16 @@
+-- keep these tests aligned with generated_stored.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +19,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -153,16 +172,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +216,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +230,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +307,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +330,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,25 +346,44 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -343,28 +396,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -381,8 +434,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -403,7 +456,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -468,7 +521,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -477,7 +530,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -492,7 +545,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -507,11 +560,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -520,7 +573,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -528,30 +581,31 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+ERROR:  relation "gtest12s" does not exist
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -560,231 +614,142 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
+ERROR:  permission denied for table gtest12v
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  index creation on virtual generated columns is not supported
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -794,6 +759,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -808,32 +778,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -844,103 +819,127 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+  tableoid   |     f1     | f2 | f3 
+-------------+------------+----+----
+ gtest_child | 07-15-2016 |  1 |  2
+ gtest_child | 07-15-2016 |  2 |  4
+(2 rows)
+
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child2 | 08-15-2016 |  3 | 66
+(1 row)
+
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
+ tableoid | f1 | f2 | f3 
+----------+----+----+----
+(0 rows)
+
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_child" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  4
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "f3" of relation "gtest_parent" is a virtual generated column.
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -953,54 +952,54 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest25" is a virtual generated column.
 SELECT * FROM gtest25 ORDER BY a;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a 
+---
+ 3
+ 4
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ERROR:  cannot use generated column "b" in column generation expression
-DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ERROR:  column "b" does not exist
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
- a | b  | c  |  x  |  d  |  y  
----+----+----+-----+-----+-----
- 3 |  9 | 42 | 168 | 101 | 404
- 4 | 12 | 42 | 168 | 101 | 404
+ a | c  |  x  |  d  |  y  
+---+----+-----+-----+-----
+ 3 | 42 | 168 | 101 | 404
+ 4 | 42 | 168 | 101 | 404
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1008,7 +1007,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1016,12 +1015,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1035,20 +1034,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1057,12 +1055,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1074,7 +1072,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1085,115 +1083,138 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 SELECT * FROM gtest29;
- a | b  
----+----
- 3 |  9
- 4 | 12
+ a | b 
+---+---
+ 3 | 6
+ 4 | 8
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
- 3 |  9
- 4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 3 |  6
+ 4 |  8
+ 5 | 10
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1246,7 +1267,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1256,12 +1277,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1271,8 +1292,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1283,6 +1304,8 @@ SELECT * FROM gtest26 ORDER BY a;
 DROP TRIGGER gtest1 ON gtest26;
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
+-- check disallowed modification of virtual columns
+-- TODO
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -1296,9 +1319,11 @@ $$;
 CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func3();
+ERROR:  virtual generated columns are not supported as trigger columns
+DETAIL:  Column "b" is a virtual generated column.
 UPDATE gtest26 SET a = 1 WHERE a = 0;
-NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
+ERROR:  trigger "gtest11" for table "gtest26" does not exist
 TRUNCATE gtest26;
 -- check that modifications of stored generated columns in triggers do
 -- not get propagated
@@ -1322,14 +1347,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1337,22 +1361,22 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index 6d127c19f47..af765edf31c 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 81e4222d26a..782d7d11dcb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 49fa9758b40..8b5cd5b38df 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -898,6 +898,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index dea8942c71f..63fd897969a 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..02fa17386c4 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,8 @@
+-- keep these tests aligned with generated_virtual.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -142,6 +155,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 
@@ -390,6 +404,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
@@ -417,6 +435,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,6 +447,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -549,6 +573,18 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 69%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..cb727c44cfb 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,58 @@
+-- keep these tests aligned with generated_stored.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -70,7 +75,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +98,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +147,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +178,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +239,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +254,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +265,172 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+SELECT a, c FROM gtest12v;  -- not allowed; TODO: ought to be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +438,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -427,6 +451,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -435,6 +462,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
@@ -457,21 +487,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +509,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +523,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +535,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +562,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +571,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -549,10 +579,22 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -614,6 +656,9 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
 DROP TRIGGER gtest2 ON gtest26;
 DROP TRIGGER gtest3 ON gtest26;
 
+-- check disallowed modification of virtual columns
+-- TODO
+
 -- Check that an UPDATE of "a" fires the trigger for UPDATE OF b, per
 -- SQL standard.
 CREATE FUNCTION gtest_trigger_func3() RETURNS trigger
@@ -667,7 +712,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index eab7d99003e..1557f200cf5 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 211b54c3162..a721bb573b1 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,10 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +56,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +69,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +88,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");

base-commit: db22b900244d3c51918acce44cbe5bb6f6507d32
-- 
2.47.0

From 09f9484f0d2990b4b9be8d2a8b907c134d6d5ee7 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 28 Nov 2024 10:23:26 +0100
Subject: [PATCH] Fix handling of CREATE DOMAIN with GENERATED constraint
 syntax

Stuff like

    CREATE DOMAIN foo AS int CONSTRAINT cc GENERATED ALWAYS AS (2) STORED

is not supported for domains, but the parser allows it, because it's
the same syntax as for table constraints.  But CreateDomain() did not
explicitly handle all ConstrType values, so the above would get an
internal error like

    ERROR:  unrecognized constraint subtype: 4

Fix that by providing a user-facing error message for all ConstrType
values.  Also, remove the switch default case, so future additions to
ConstrType are caught.

Reported-by: Jian He <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/CACJufxF8fmM=Dbm4pDFuV_nKGz2-No0k4YifhrF3-rjXTWJM3w@mail.gmail.com
---
 src/backend/commands/typecmds.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 859e2191f08..130741e777e 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -1011,10 +1011,14 @@ DefineDomain(CreateDomainStmt *stmt)
 						 errmsg("specifying constraint deferrability not supported for domains")));
 				break;
 
-			default:
-				elog(ERROR, "unrecognized constraint subtype: %d",
-					 (int) constr->contype);
+			case CONSTR_GENERATED:
+			case CONSTR_IDENTITY:
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("specifying GENERATED not supported for domains")));
 				break;
+
+				/* no default, to let compiler warn about missing case */
 		}
 	}
 
-- 
2.47.0

From b7e8a67e963af585a037ec9a586267f215139585 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Fri, 29 Nov 2024 09:45:32 +0100
Subject: [PATCH v10] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

The syntax for the column definition is

    ... GENERATED ALWAYS AS (...) VIRTUAL

and VIRTUAL is also optional.  VIRTUAL is the default rather than
STORED to match various other SQL products.  (The SQL standard makes
no specification about this, but it also doesn't know about VIRTUAL or
STORED.)  (Also, virtual views are the default, rather than
materialized views.)

Virtual generated columns are stored in tuples as null values.  (A
very early version of this patch had the ambition to not store them at
all.  But so much stuff breaks or gets confused if you have tuples
where a column in the middle is completely missing.  This is a
compromise, and it still saves space over being forced to use stored
generated columns.  If we ever find a way to improve this, a bit of
pg_upgrade cleverness could allow for upgrades to a newer scheme.)

The capabilities and restrictions of virtual generated columns are
mostly the same as for stored generated columns.  In some cases, this
patch keeps virtual generated columns more restricted than they might
technically need to be, to keep the two kinds consistent.  Some of
that could maybe be relaxed later after separate careful
considerations.

Some functionality that is currently not supported, but could possibly
be added as incremental features, some easier than others:

- index on or using a virtual column
- hence also no unique constraints on virtual columns
- extended statistics on virtual columns
- foreign key constraints on virtual columns
- not-null constraints on virtual columns (check constraints are supported)
- ALTER TABLE / DROP EXPRESSION
- virtual column cannot have domain type

The tests in generated_virtual.sql have been copied over from
generated_stored.sql with the keyword replaced.  This way we can make
sure the behavior is mostly aligned, and the differences can be
visible.  Some tests for currently not supported features are
currently commented out.

TODO:
- handling of publication option publish_generated_columns

contributions by Jian He, Dean Rasheed

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   6 +-
 doc/src/sgml/ddl.sgml                         |  45 +-
 doc/src/sgml/ref/alter_table.sgml             |  11 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  23 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  33 +-
 src/backend/commands/publicationcmds.c        |   3 +
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 196 +++-
 src/backend/commands/trigger.c                |  44 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/executor/execUtils.c              |   4 +-
 src/backend/executor/nodeModifyTable.c        |  25 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  16 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 115 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/executor/nodeModifyTable.h        |   6 +-
 src/include/nodes/execnodes.h                 |   3 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     |  83 +-
 ...rated_stored.out => generated_virtual.out} | 835 +++++++++---------
 src/test/regress/expected/publication.out     |  18 +-
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  43 +-
 ...rated_stored.sql => generated_virtual.sql} | 321 ++++---
 src/test/regress/sql/publication.sql          |  14 +-
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/subscription/t/011_generated.pl      |  39 +-
 src/test/subscription/t/028_row_filter.pl     |  38 +-
 66 files changed, 1642 insertions(+), 742 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (68%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (68%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index f2bcd6aa98c..614e8135e0e 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 372fe6dad15..32e16bfc0e2 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 59bb833f48d..efcf12a596a 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1318,8 +1318,10 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.  A stored generated column is physically stored like a normal
+       column.  A virtual generated column is physically stored as a null
+       value, with the actual value being computed at run time.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 08155b156a5..b0ed16a9d30 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
@@ -502,6 +507,26 @@ <title>Generated Columns</title>
       particular role can read from a generated column but not from the
       underlying base columns.
      </para>
+
+     <para>
+      For virtual generated columns, this is only fully secure if the
+      generation expression uses only leakproof functions (see <xref
+      linkend="sql-createfunction"/>), but this is not enforced by the system.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Privileges of functions used in generation expressions are checked when
+      the expression is actually executed, on write or read respectively, as
+      if the generation expression had been called directly from the query
+      using the generated column.  The user of a generated column must have
+      permissions to call all functions used by the generation expression.
+      Functions in the generation expression are executed with the privileges
+      of the user executing the query or the function owner, depending on
+      whether the functions are defined as <literal>SECURITY INVOKER</literal>
+      or <literal>SECURITY DEFINER</literal>.
+      <!-- matches create_view.sgml -->
+     </para>
     </listitem>
     <listitem>
      <para>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c8f7ab7d956..3c1e1b77beb 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -279,10 +279,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index fc81ba3c498..7fe13e6e584 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -281,7 +281,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -290,10 +290,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 1a1adc5ae87..5b7d428e2df 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2457,9 +2461,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index a9abaab9056..46c6c2f126f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 47379fef220..13840ba533c 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -190,6 +190,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -494,6 +495,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a8d95e0f1c1..ecc3f599b41 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index d7b88b61dcc..165ebae9abd 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -512,7 +512,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -587,6 +587,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
@@ -2560,6 +2571,11 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
+			/* TODO: see transformColumnDefinition() */
+			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("not-null constraints are not supported on virtual generated columns")));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2848,6 +2864,11 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					errmsg("cannot add not-null constraint on system column \"%s\"",
 						   strVal(linitial(constr->keys))));
+		/* TODO: see transformColumnDefinition() */
+		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 9a56de2282f..ba7b28523d9 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 4049ce1a10f..becbd556e48 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1111,6 +1111,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1120,14 +1123,24 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 stmt->isconstraint ?
+					 errmsg("unique constraints on virtual generated columns are not supported") :
+					 errmsg("indexes on virtual generated columns are not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1140,6 +1153,24 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 stmt->isconstraint ?
+						 errmsg("unique constraints on virtual generated columns are not supported") :
+						 errmsg("indexes on virtual generated columns are not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 031c84ec29f..3dc873fdc07 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -38,6 +38,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parse_collate.h"
 #include "parser/parse_relation.h"
+#include "rewrite/rewriteHandler.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -661,6 +662,8 @@ TransformPubWhereClauses(List *tables, const char *queryString,
 		/* Fix up collation information */
 		assign_expr_collations(pstate, whereclause);
 
+		whereclause = (Node *) expand_generated_columns_in_expr(whereclause, pri->relation, 1);
+
 		/*
 		 * We allow only simple expressions in row filters. See
 		 * check_simple_rowfilter_expr_walker.
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 1db3ef69d22..744b3508c24 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6ccae4cb4a8..28623672fa0 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3020,6 +3020,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3292,6 +3301,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6093,7 +6111,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7271,7 +7289,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7748,6 +7766,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8374,6 +8400,8 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	HeapTuple	tuple;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
+	char		attgenerated;
+	bool		rewrite;
 	Oid			attrdefoid;
 	ObjectAddress address;
 	Expr	   *defval;
@@ -8388,36 +8416,70 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 						colName, RelationGetRelationName(rel))));
 
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
-	attnum = attTup->attnum;
 
+	attnum = attTup->attnum;
 	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	attgenerated = attTup->attgenerated;
+	if (!attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 						colName, RelationGetRelationName(rel))));
-	ReleaseSysCache(tuple);
 
 	/*
-	 * Clear all the missing values if we're rewriting the table, since this
-	 * renders them pointless.
+	 * TODO: This could be done, just need to recheck any constraints
+	 * afterwards.
 	 */
-	RelationClearMissing(rel);
-
-	/* make sure we don't conflict with later attribute modifications */
-	CommandCounterIncrement();
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Find everything that depends on the column (constraints, indexes, etc),
-	 * and record enough information to let us recreate the objects after
-	 * rewrite.
+	 * We need to prevent this because a change of expression could affect a
+	 * row filter and inject expressions that are not permitted in a row
+	 * filter.  XXX We could try to have a more precise check to catch only
+	 * publications with row filters, or even re-verify the row filter
+	 * expressions.
 	 */
-	RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		GetRelationPublications(RelationGetRelid(rel)) != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
+
+	ReleaseSysCache(tuple);
+
+	if (rewrite)
+	{
+		/*
+		 * Clear all the missing values if we're rewriting the table, since
+		 * this renders them pointless.
+		 */
+		RelationClearMissing(rel);
+
+		/* make sure we don't conflict with later attribute modifications */
+		CommandCounterIncrement();
+
+		/*
+		 * Find everything that depends on the column (constraints, indexes,
+		 * etc), and record enough information to let us recreate the objects
+		 * after rewrite.
+		 */
+		RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	}
 
 	/*
 	 * Drop the dependency records of the GENERATED expression, in particular
@@ -8446,7 +8508,7 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	rawEnt->attnum = attnum;
 	rawEnt->raw_default = newExpr;
 	rawEnt->missingMode = false;
-	rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
+	rawEnt->generated = attgenerated;
 
 	/* Store the generated expression */
 	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
@@ -8455,16 +8517,19 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	/* Make above new expression visible */
 	CommandCounterIncrement();
 
-	/* Prepare for table rewrite */
-	defval = (Expr *) build_column_default(rel, attnum);
+	if (rewrite)
+	{
+		/* Prepare for table rewrite */
+		defval = (Expr *) build_column_default(rel, attnum);
 
-	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
-	newval->attnum = attnum;
-	newval->expr = expression_planner(defval);
-	newval->is_generated = true;
+		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+		newval->attnum = attnum;
+		newval->expr = expression_planner(defval);
+		newval->is_generated = true;
 
-	tab->newvals = lappend(tab->newvals, newval);
-	tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+		tab->newvals = lappend(tab->newvals, newval);
+		tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+	}
 
 	/* Drop any pg_statistic entry for the column */
 	RemoveStatistics(RelationGetRelid(rel), attnum);
@@ -8553,17 +8618,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8706,6 +8784,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9898,6 +9986,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12099,7 +12200,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -13285,8 +13386,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13359,11 +13464,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16349,6 +16455,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18584,8 +18698,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18667,9 +18784,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 09356e46d16..473541a2d21 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -2503,6 +2506,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3060,6 +3065,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3490,6 +3497,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6600,3 +6609,36 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and error if
+ * so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ *
+ * Alternatively, we could fix erroneous tuples here and be silent about it.
+ * This would yield the same user-facing behavior for virtual and stored
+ * generated columns.  But it seems more complicated and not very useful in
+ * practice.
+ */
+static void
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			if (!heap_attisnull(tuple, i + 1, tupdesc))
+				ereport(ERROR,
+						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
+						 errmsg("trigger modified virtual generated column value")));
+		}
+	}
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index bad7b195bfb..e36488a4aa0 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2133,6 +2133,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 5ca856fd279..e49acc20845 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1757,6 +1757,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2304,7 +2305,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 740e8fb1486..5e1bac04ee3 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1311,8 +1311,8 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (relinfo->ri_GeneratedExprsU == NULL)
-		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+	if (!relinfo->ri_Generated_valid)
+		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 1161520f76b..fc488231f32 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -349,9 +349,9 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-						EState *estate,
-						CmdType cmdtype)
+ExecInitGenerated(ResultRelInfo *resultRelInfo,
+				  EState *estate,
+				  CmdType cmdtype)
 {
 	Relation	rel = resultRelInfo->ri_RelationDesc;
 	TupleDesc	tupdesc = RelationGetDescr(rel);
@@ -362,7 +362,7 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
+	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
 		return;
 
 	/*
@@ -388,7 +388,9 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated)
 		{
 			Expr	   *expr;
 
@@ -413,8 +415,11 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-			ri_NumGeneratedNeeded++;
+			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
+			{
+				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+				ri_NumGeneratedNeeded++;
+			}
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -442,6 +447,8 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
+	resultRelInfo->ri_Generated_valid = true;
+
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -472,7 +479,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -480,7 +487,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 67eb96396af..242a18cf78d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -628,7 +628,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -776,7 +776,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3985,7 +3985,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3993,6 +3993,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4039,6 +4040,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17921,6 +17928,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18575,6 +18583,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 8075b1b8a1b..6f8f96b34da 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 0f324ee4e31..929ed4fa806 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -986,6 +986,20 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns"),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 5e23453f071..d3de5854529 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1000,7 +1001,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index ab2e2cd6476..889b9156d5e 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -980,7 +981,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2203,6 +2205,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2216,10 +2222,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2308,6 +2315,14 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
+																rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4419,6 +4434,96 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+/*
+ * Expand virtual generated columns in an expression
+ *
+ * This is for expressions that are not part of a query, such as default
+ * expressions or index predicates.  The rt_index is usually 1.
+ */
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index d0892cee24d..668924e9ceb 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -590,6 +590,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -686,6 +688,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index add7f16c902..23e85bdcbef 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16188,6 +16188,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index aa1564cd450..8fc981d52e9 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3641,12 +3641,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 0aa39906a11..80dec7291a9 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2106,6 +2106,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index 8930a28d660..6ef40249583 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 8c278f202b4..ec95d9ba7f1 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 1c62b8bfcb5..8f158dc6083 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -234,6 +234,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index 681cdaa89db..0d8a5f66131 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,9 +15,9 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-									EState *estate,
-									CmdType cmdtype);
+extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+							  EState *estate,
+							  CmdType cmdtype);
 
 extern void ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 									   EState *estate, TupleTableSlot *slot,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 182a6956bb0..5acf3c29dec 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -540,6 +540,9 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
+	/* true if the above have been computed */
+	bool		ri_Generated_valid;
+
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 0f9462493e3..07204b7bf62 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2765,6 +2765,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 899d64ad55f..efe25d7de0f 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -490,6 +490,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 1b65cda71cf..8ec879193e2 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index e2d9246a678..a50bd1cd1ea 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 79e76d4b850..472407babd6 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2467,6 +2467,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index d091da5a1ef..490ec986b35 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 0d037d48ca0..4374bf55d23 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,5 +1,6 @@
+-- keep these tests aligned with generated_virtual.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -217,6 +236,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -312,6 +352,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -547,7 +591,7 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 ERROR:  permission denied for table gtest11s
@@ -560,7 +604,9 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
  a | c  
 ---+----
  1 | 30
@@ -764,6 +810,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -794,6 +845,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -807,6 +863,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1094,9 +1155,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1190,6 +1251,18 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 68%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 0d037d48ca0..042e184ea0e 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,16 @@
+-- keep these tests aligned with generated_stored.sql
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +19,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -128,6 +129,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -153,16 +172,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +216,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +230,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +307,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +330,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,25 +346,44 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -343,28 +396,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -381,8 +434,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -403,7 +456,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -468,7 +521,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -477,7 +530,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -492,7 +545,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -507,11 +560,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -520,7 +573,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -528,30 +581,30 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -560,231 +613,152 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
+DETAIL:  Failing row contains (30, virtual).
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+LINE 1: ... b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+                                                             ^
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+DROP TABLE gtest21ax;
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  unique constraints on virtual generated columns are not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -794,6 +768,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -808,32 +787,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -844,103 +828,121 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+  tableoid   |     f1     | f2 | f3 
+-------------+------------+----+----
+ gtest_child | 07-15-2016 |  1 |  2
+ gtest_child | 07-15-2016 |  2 |  4
+(2 rows)
+
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child2 | 08-15-2016 |  3 | 66
+(1 row)
+
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
+ tableoid | f1 | f2 | f3 
+----------+----+----+----
+(0 rows)
+
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 4)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 10)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  8
+ gtest_child2 | 08-15-2016 |  3 | 12
+ gtest_child3 | 09-13-2016 |  1 |  4
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -953,20 +955,20 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
  a | b  
 ---+----
@@ -974,16 +976,16 @@ SELECT * FROM gtest25 ORDER BY a;
  4 | 12
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
 ERROR:  cannot use generated column "b" in column generation expression
 DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
  a | b  | c  |  x  |  d  |  y  
 ---+----+----+-----+-----+-----
@@ -992,15 +994,15 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
+ b      | integer          |           |          | generated always as (a * 3)
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1008,7 +1010,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1016,12 +1018,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1035,20 +1037,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1057,12 +1058,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1074,7 +1075,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1085,18 +1086,18 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1107,93 +1108,114 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 3)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
  3 |  9
  4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 5 | 15
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1246,7 +1268,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1256,12 +1278,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1271,8 +1293,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1300,7 +1322,7 @@ UPDATE gtest26 SET a = 1 WHERE a = 0;
 NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -1322,14 +1344,13 @@ CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: old = (1,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
-INFO:  gtest12_03: BEFORE: new = (10,)
+ERROR:  trigger modified virtual generated column value
 SELECT * FROM gtest26 ORDER BY a;
- a  | b  
-----+----
- 10 | 20
+ a | b 
+---+---
+ 1 | 2
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -1337,22 +1358,22 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index 5de2d64d01a..3b3c6999d6c 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -442,7 +442,7 @@ LINE 1: ...ICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
                                                              ^
 DETAIL:  User-defined operators are not allowed.
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 ERROR:  invalid publication WHERE expression
 LINE 1: ...ON testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf...
@@ -523,17 +523,33 @@ Tables:
 Tables from schemas:
     "testpub_rf_schema2"
 
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+ERROR:  invalid publication WHERE expression
+DETAIL:  User-defined or built-in mutable functions are not allowed.
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication
+DETAIL:  Column "y" of relation "testpub_rf_tbl7" is a virtual generated column.
+RESET client_min_messages;
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index fd5654df35e..87929191d06 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 81e4222d26a..782d7d11dcb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 797e93ac714..4bc4ff465b9 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -920,6 +920,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index dea8942c71f..63fd897969a 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..d0aa91b9657 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,8 @@
+-- keep these tests aligned with generated_virtual.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -142,6 +155,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 
@@ -278,13 +292,14 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 SELECT a, c FROM gtest11s;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
@@ -390,6 +405,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
@@ -417,6 +436,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,6 +448,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -549,6 +574,18 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 68%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..f97060ead47 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,58 @@
+-- keep these tests aligned with generated_stored.sql
+
+
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -60,6 +63,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -70,7 +75,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +98,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +108,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +147,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +178,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +239,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +254,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +265,179 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
 ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+DROP TABLE gtest21ax;
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +445,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -427,6 +458,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -435,6 +469,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
@@ -457,21 +494,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +516,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +530,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +542,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +569,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +578,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -549,10 +586,22 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -634,7 +683,7 @@ CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
 
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -667,7 +716,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index 48e68bcca2d..aee30af035e 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -214,7 +214,7 @@ CREATE FUNCTION testpub_rf_func1(integer, integer) RETURNS boolean AS $$ SELECT
 CREATE OPERATOR =#> (PROCEDURE = testpub_rf_func1, LEFTARG = integer, RIGHTARG = integer);
 CREATE PUBLICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 -- fail - non-immutable functions are not allowed. random() is volatile.
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a < random());
@@ -261,18 +261,30 @@ CREATE PUBLICATION testpub6 FOR TABLES IN SCHEMA testpub_rf_schema2;
 ALTER PUBLICATION testpub6 SET TABLES IN SCHEMA testpub_rf_schema2, TABLE testpub_rf_schema2.testpub_rf_tbl6 WHERE (i < 99);
 RESET client_min_messages;
 \dRp+ testpub6
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+RESET client_min_messages;
 
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index cf09f62eaba..f61dbbf9581 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index b1b87cf85e3..a28dc3e489b 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,11 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +57,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +70,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +89,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");
diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl
index 2acd36d7a6f..97cb43f450b 100644
--- a/src/test/subscription/t/028_row_filter.pl
+++ b/src/test/subscription/t/028_row_filter.pl
@@ -240,6 +240,9 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync PARTITION OF tab_rowfilter_parent_sync FOR VALUES FROM (1) TO (20)"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup structure on subscriber
 $node_subscriber->safe_psql('postgres',
@@ -294,6 +297,9 @@
 	"CREATE TABLE tab_rowfilter_parent_sync (a int)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync (a int)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup logical replication
 $node_publisher->safe_psql('postgres',
@@ -359,6 +365,11 @@
 	"CREATE PUBLICATION tap_pub_child_sync FOR TABLE tab_rowfilter_child_sync WHERE (a < 15)"
 );
 
+# publication using virtual generated column in row filter expression
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_virtual FOR TABLE tab_rowfilter_virtual WHERE (y > 10)"
+);
+
 #
 # The following INSERTs are executed before the CREATE SUBSCRIPTION, so these
 # SQL commands are for testing the initial data copy using logical replication.
@@ -407,8 +418,12 @@
 	"INSERT INTO tab_rowfilter_child(a, b) VALUES(0,'0'),(30,'30'),(40,'40')"
 );
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (1, 2), (2, 4), (3, 6)"
+);
+
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync, tap_pub_virtual"
 );
 
 # wait for initial table synchronization to finish
@@ -550,6 +565,16 @@
 	"SELECT a FROM tab_rowfilter_child_sync ORDER BY 1");
 is($result, qq(), 'check initial data copy from tab_rowfilter_child_sync');
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (1, 2)      NO, 2 * 2 <= 10
+# - INSERT (2, 4)      NO, 4 * 2 <= 10
+# - INSERT (3, 6)      YES, 6 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is($result, qq(3|6),
+	'check initial data copy from table tab_rowfilter_virtual');
+
 # The following commands are executed after CREATE SUBSCRIPTION, so these SQL
 # commands are for testing normal logical replication behavior.
 #
@@ -582,6 +607,8 @@
 	"INSERT INTO tab_rowfilter_child (a, b) VALUES (13, '13'), (17, '17')");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rowfilter_viaroot_part (a) VALUES (14), (15), (16)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (4, 3), (5, 7)");
 
 $node_publisher->wait_for_catchup($appname);
 
@@ -725,6 +752,15 @@
 	'check replicated rows to tab_rowfilter_inherited and tab_rowfilter_child'
 );
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (4, 3)      NO, 3 * 2 <= 10
+# - INSERT (5, 7)      YES, 7 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is( $result, qq(3|6
+5|7), 'check replicated rows to tab_rowfilter_virtual');
+
 # UPDATE the non-toasted column for table tab_rowfilter_toast
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_rowfilter_toast SET b = '1'");

base-commit: b6612aedc53a6bf069eba5e356a8421ad6426486
-- 
2.47.0

From 47662077d61527b3b78704ebfaffedb53f53f904 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Tue, 3 Dec 2024 22:13:55 +0800
Subject: [PATCH v10 1/1] stats_exts regress tests

stats_exts regress tests for virtual generated columns, system columns,
    columns no less than operator
---
 src/test/regress/expected/stats_ext.out | 22 ++++++++++++++++++++++
 src/test/regress/sql/stats_ext.sql      | 14 ++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index a4c7be487e..6703018317 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -54,6 +54,28 @@ CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
 ERROR:  duplicate expression in statistics definition
 CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
 ERROR:  unrecognized statistics kind "unrecognized"
+--STATISTICS on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+--STATISTICS on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+--STATISTICS, without a less-than operator not allowed
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
 -- incorrect expressions
 CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 ERROR:  extended statistics require at least 2 columns
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 5c786b16c6..12f02d0d9a 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -40,6 +40,20 @@ CREATE STATISTICS tst ON x, x, y, x, x, (x || 'x'), (y + 1), (x || 'x'), (x || '
 CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1), (x || 'x'), (x || 'x'), (y + 1) FROM ext_stats_test;
 CREATE STATISTICS tst ON (x || 'x'), (x || 'x'), y FROM ext_stats_test;
 CREATE STATISTICS tst (unrecognized) ON x, y FROM ext_stats_test;
+--STATISTICS on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+--STATISTICS on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+--STATISTICS, without a less-than operator not allowed
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+
 -- incorrect expressions
 CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
-- 
2.34.1

From ea27806ed7ce524cff66d2f250e9625ae96bdc26 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Tue, 3 Dec 2024 17:04:55 +0800
Subject: [PATCH v10 1/1] refactor ExecGetExtraUpdatedCols

---
 src/backend/executor/execUtils.c       | 68 ++++++++++++++++++++++++--
 src/backend/executor/nodeModifyTable.c | 21 +++-----
 src/include/executor/nodeModifyTable.h |  2 +-
 src/include/nodes/execnodes.h          |  3 --
 4 files changed, 73 insertions(+), 21 deletions(-)

diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 5e1bac04ee..81afeabdf9 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -55,6 +55,8 @@
 #include "miscadmin.h"
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
+#include "rewrite/rewriteHandler.h"
+#include "optimizer/optimizer.h"
 #include "storage/lmgr.h"
 #include "utils/builtins.h"
 #include "utils/memutils.h"
@@ -1306,13 +1308,73 @@ ExecGetUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 	return perminfo->updatedCols;
 }
 
-/* Return a bitmap representing generated columns being updated */
+/* Return a bitmap representing (viirtual|stored) generated columns being
+ * updated first, through ExecInitStoredGenerated colect all stored generated
+ * column.  then collect the virtual one.
+*/
 Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
+	Relation	rel = relinfo->ri_RelationDesc;
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+	int			natts = tupdesc->natts;
+	Bitmapset  *updatedCols;
+	MemoryContext oldContext;
+
 	/* Compute the info if we didn't already */
-	if (!relinfo->ri_Generated_valid)
-		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
+	if (relinfo->ri_GeneratedExprsU == NULL)
+		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+
+	/* Nothing else to do if no virtual generated columns */
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return relinfo->ri_extraUpdatedCols;
+
+	/*
+	 * In an UPDATE, we can skip computing any generated columns that do not
+	 * depend on any UPDATE target column.  But if there is a BEFORE ROW
+	 * UPDATE trigger, we cannot skip because the trigger might change more
+	 * columns.
+	 */
+	if (!(rel->trigdesc && rel->trigdesc->trig_update_before_row))
+		updatedCols = ExecGetUpdatedCols(relinfo, estate);
+	else
+		updatedCols = NULL;
+
+	oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
+	for (int i = 0; i < natts; i++)
+	{
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			Expr	   *expr;
+
+			/* Fetch the GENERATED AS expression tree */
+			expr = (Expr *) build_column_default(rel, i + 1);
+			if (expr == NULL)
+				elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+					 i + 1, RelationGetRelationName(rel));
+
+			/*
+			 * If it's an update with a known set of update target columns,
+			 * see if we can skip the computation.
+			 */
+			if (updatedCols)
+			{
+				Bitmapset  *attrs_used = NULL;
+
+				pull_varattnos((Node *) expr, 1, &attrs_used);
+
+				if (!bms_overlap(updatedCols, attrs_used))
+					continue;	/* need not update this column */
+			}
+
+			relinfo->ri_extraUpdatedCols =
+				bms_add_member(relinfo->ri_extraUpdatedCols,
+								i + 1 - FirstLowInvalidHeapAttributeNumber);
+		}
+	}
+	MemoryContextSwitchTo(oldContext);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index fc488231f3..3a8dbe6dd7 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -349,7 +349,7 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitGenerated(ResultRelInfo *resultRelInfo,
+ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 				  EState *estate,
 				  CmdType cmdtype)
 {
@@ -362,7 +362,7 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
 		return;
 
 	/*
@@ -388,9 +388,7 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
-
-		if (attgenerated)
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
 		{
 			Expr	   *expr;
 
@@ -415,11 +413,8 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
-			{
-				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-				ri_NumGeneratedNeeded++;
-			}
+			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+			ri_NumGeneratedNeeded++;
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -447,8 +442,6 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
-	resultRelInfo->ri_Generated_valid = true;
-
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -479,7 +472,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -487,7 +480,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index 0d8a5f6613..2e6a2bab20 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,7 +15,7 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 							  EState *estate,
 							  CmdType cmdtype);
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 5acf3c29de..182a6956bb 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -540,9 +540,6 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
-	/* true if the above have been computed */
-	bool		ri_Generated_valid;
-
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
-- 
2.34.1

From 5ad183eab1525a58a0bf20fb798fec8ef5d90893 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Wed, 11 Dec 2024 14:45:52 +0800
Subject: [PATCH v10 1/1] overwritten virtual generated column value to null in
 trigger

overwritten trigger assign values for virtual generated column to null.
so virtual and stored generated column trigger bahavior is more aligned.
---
 doc/src/sgml/trigger.sgml                     |  2 +-
 src/backend/commands/trigger.c                | 77 ++++++++++---------
 src/pl/plpgsql/src/pl_exec.c                  |  4 +-
 .../regress/expected/generated_virtual.out    | 21 ++---
 src/test/regress/sql/generated_virtual.sql    |  8 +-
 5 files changed, 61 insertions(+), 51 deletions(-)

diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index 46c6c2f126..3a91eae156 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -287,7 +287,7 @@
     higher-level programming language should prevent access to a stored
     generated column in the <literal>NEW</literal> row in a
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
-    column in a <literal>BEFORE</literal> trigger are ignored and will be
+    column (stored or virtual) in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
     Virtual generated columns are never computed when triggers fire.  In the C
     language interface, their content is undefined in a trigger function.
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 473541a2d2..d304ac8072 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -102,7 +102,6 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
-static void check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -2506,7 +2505,26 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
-			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+			TupleDesc tupdesc = RelationGetDescr(relinfo->ri_RelationDesc);
+			/*
+			 * set virtual generated columns value to null if them are not null.
+			 * see ExecBRUpdateTriggers comments. also
+			 */
+			if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+			{
+				Datum		replValues = 0;
+				bool		replIsnull = true;
+				for (int j = 1; j <= tupdesc->natts; j++)
+				{
+					if ((TupleDescAttr(tupdesc, j-1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+						&& !heap_attisnull(newtuple, j, tupdesc))
+						newtuple = heap_modify_tuple_by_cols(newtuple, tupdesc,
+															 1,
+															 &j,
+															 &replValues,
+															 &replIsnull);
+				}
+			}
 
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
@@ -3065,7 +3083,27 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
-			check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+			TupleDesc tupdesc = RelationGetDescr(relinfo->ri_RelationDesc);
+			/*
+			 * virtual generated columns have no storage, them will not insert to the
+			 * table, so if any trigger set them to not-null value, set it to
+			 * null again. this apply to ExecBRInsertTriggers also.
+			 */
+			if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+			{
+				Datum		replValues = 0;
+				bool		replIsnull = true;
+				for (int j = 1; j <= tupdesc->natts; j++)
+				{
+					if ((TupleDescAttr(tupdesc, j-1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+						&& !heap_attisnull(newtuple, j, tupdesc))
+						newtuple = heap_modify_tuple_by_cols(newtuple, tupdesc,
+															 1,
+															 &j,
+															 &replValues,
+															 &replIsnull);
+				}
+			}
 
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
@@ -6609,36 +6647,3 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
-
-/*
- * Check whether a trigger modified a virtual generated column and error if
- * so.
- *
- * We need to check this so that we don't end up storing a non-null value in a
- * virtual generated column.
- *
- * We don't need to check for stored generated columns, since those will be
- * overwritten later anyway.
- *
- * Alternatively, we could fix erroneous tuples here and be silent about it.
- * This would yield the same user-facing behavior for virtual and stored
- * generated columns.  But it seems more complicated and not very useful in
- * practice.
- */
-static void
-check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
-{
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
-		return;
-
-	for (int i = 0; i < tupdesc->natts; i++)
-	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
-		{
-			if (!heap_attisnull(tuple, i + 1, tupdesc))
-				ereport(ERROR,
-						(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
-						 errmsg("trigger modified virtual generated column value")));
-		}
-	}
-}
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index e31206e7f4..9bb7d6621a 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -992,12 +992,14 @@ plpgsql_exec_trigger(PLpgSQL_function *func,
 		 * still contains the old value.)  Alternatively, we could construct a
 		 * whole new row structure without the generated columns, but this way
 		 * seems more efficient and potentially less confusing.
+		 * we also make virtual generated columns be null in the NEW row.
 		 */
 		if (tupdesc->constr && tupdesc->constr->has_generated_stored &&
 			TRIGGER_FIRED_BEFORE(trigdata->tg_event))
 		{
 			for (int i = 0; i < tupdesc->natts; i++)
-				if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+				if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED ||
+					TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 					expanded_record_set_field_internal(rec_new->erh,
 													   i + 1,
 													   (Datum) 0,
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 042e184ea0..7dbda2b67d 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1333,24 +1333,27 @@ BEGIN
   RETURN NEW;
 END;
 $$;
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,)
+INFO:  gtest12_01: BEFORE: new = (1,)
+INFO:  gtest12_03: BEFORE: new = (10,)
+UPDATE gtest26 SET a = 11 WHERE a = 10;
+INFO:  gtest12_01: BEFORE: old = (10,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-ERROR:  trigger modified virtual generated column value
+INFO:  gtest12_03: BEFORE: old = (10,)
+INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
- a | b 
----+---
- 1 | 2
+ a  | b  
+----+----
+ 10 | 20
 (1 row)
 
 -- LIKE INCLUDING GENERATED and dropped column handling
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index f97060ead4..2b0fc159af 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -695,20 +695,20 @@ BEGIN
 END;
 $$;
 
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
 
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE UPDATE OR INSERT ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
+UPDATE gtest26 SET a = 11 WHERE a = 10;
 SELECT * FROM gtest26 ORDER BY a;
 
 -- LIKE INCLUDING GENERATED and dropped column handling
-- 
2.34.1

From f685d2b6dd5dbc7a34234b6b3cdbd9f2aef1c29d Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 16 Dec 2024 20:22:16 +0800
Subject: [PATCH v10 1/1] make ALTER TABLE SET EXPRESSION an no-op if not
 changed

if new and old generated expression is the same,
make ALTER TABLE ALTER COLUMN SET EXPRESSION a no-op.
---
 src/backend/commands/tablecmds.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 28623672fa..effa3767e4 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8407,6 +8407,11 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	Expr	   *defval;
 	NewColumnValue *newval;
 	RawColumnDefault *rawEnt;
+	ParseState *pstate;
+	Node	   *expr;
+	Node	   *old_default;
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+	ParseNamespaceItem *nsitem;
 
 	tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
 	if (!HeapTupleIsValid(tuple))
@@ -8462,6 +8467,24 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 
 	ReleaseSysCache(tuple);
 
+	old_default = TupleDescGetDefault(tupdesc, attnum);
+	pstate = make_parsestate(NULL);
+	pstate->p_sourcetext = NULL;
+	nsitem = addRangeTableEntryForRelation(pstate,
+										   rel,
+										   AccessShareLock,
+										   NULL,
+										   false,
+										   true);
+	addNSItemToQuery(pstate, nsitem, true, true, true);
+	expr = cookDefault(pstate, newExpr,
+					   attTup->atttypid, attTup->atttypmod,
+					   NameStr(attTup->attname),
+					   attTup->attgenerated);
+
+	if(equal(expr, old_default))
+		return InvalidObjectAddress;
+
 	if (rewrite)
 	{
 		/*
-- 
2.34.1

From 801cf024f688667fff4eb62a1bca6ec27c96d78b Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 8 Jan 2025 16:59:42 +0100
Subject: [PATCH v11] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

The syntax for the column definition is

    ... GENERATED ALWAYS AS (...) VIRTUAL

and VIRTUAL is also optional.  VIRTUAL is the default rather than
STORED to match various other SQL products.  (The SQL standard makes
no specification about this, but it also doesn't know about VIRTUAL or
STORED.)  (Also, virtual views are the default, rather than
materialized views.)

Virtual generated columns are stored in tuples as null values.  (A
very early version of this patch had the ambition to not store them at
all.  But so much stuff breaks or gets confused if you have tuples
where a column in the middle is completely missing.  This is a
compromise, and it still saves space over being forced to use stored
generated columns.  If we ever find a way to improve this, a bit of
pg_upgrade cleverness could allow for upgrades to a newer scheme.)

The capabilities and restrictions of virtual generated columns are
mostly the same as for stored generated columns.  In some cases, this
patch keeps virtual generated columns more restricted than they might
technically need to be, to keep the two kinds consistent.  Some of
that could maybe be relaxed later after separate careful
considerations.

Some functionality that is currently not supported, but could possibly
be added as incremental features, some easier than others:

- index on or using a virtual column
- hence also no unique constraints on virtual columns
- extended statistics on virtual columns
- foreign key constraints on virtual columns
- not-null constraints on virtual columns (check constraints are supported)
- ALTER TABLE / DROP EXPRESSION
- virtual column cannot have domain type

The tests in generated_virtual.sql have been copied over from
generated_stored.sql with the keyword replaced.  This way we can make
sure the behavior is mostly aligned, and the differences can be
visible.  Some tests for currently not supported features are
currently commented out.

TODO:
- handling of publication option publish_generated_columns

contributions by Jian He, Dean Rasheed

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   6 +-
 doc/src/sgml/ddl.sgml                         |  45 +-
 doc/src/sgml/ref/alter_table.sgml             |  15 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  23 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  33 +-
 src/backend/commands/publicationcmds.c        |   3 +
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 196 +++-
 src/backend/commands/trigger.c                |  45 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/executor/execUtils.c              |   4 +-
 src/backend/executor/nodeModifyTable.c        |  41 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  16 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 115 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/executor/nodeModifyTable.h        |   6 +-
 src/include/nodes/execnodes.h                 |   3 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     | 113 ++-
 ...rated_stored.out => generated_virtual.out} | 858 +++++++++---------
 src/test/regress/expected/publication.out     |  18 +-
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/expected/stats_ext.out       |  23 +
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  54 +-
 ...rated_stored.sql => generated_virtual.sql} | 336 ++++---
 src/test/regress/sql/publication.sql          |  14 +-
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/regress/sql/stats_ext.sql            |  14 +
 src/test/subscription/t/011_generated.pl      |  39 +-
 src/test/subscription/t/028_row_filter.pl     |  38 +-
 68 files changed, 1744 insertions(+), 777 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (67%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index bf322198a20..32d581e8422 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 3900522ccb5..71a27282138 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index cc6cf9bef09..1f5906624bd 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1307,8 +1307,10 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.  A stored generated column is physically stored like a normal
+       column.  A virtual generated column is physically stored as a null
+       value, with the actual value being computed at run time.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index dea04d64db6..502dd154645 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
@@ -502,6 +507,26 @@ <title>Generated Columns</title>
       particular role can read from a generated column but not from the
       underlying base columns.
      </para>
+
+     <para>
+      For virtual generated columns, this is only fully secure if the
+      generation expression uses only leakproof functions (see <xref
+      linkend="sql-createfunction"/>), but this is not enforced by the system.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Privileges of functions used in generation expressions are checked when
+      the expression is actually executed, on write or read respectively, as
+      if the generation expression had been called directly from the query
+      using the generated column.  The user of a generated column must have
+      permissions to call all functions used by the generation expression.
+      Functions in the generation expression are executed with the privileges
+      of the user executing the query or the function owner, depending on
+      whether the functions are defined as <literal>SECURITY INVOKER</literal>
+      or <literal>SECURITY DEFINER</literal>.
+      <!-- matches create_view.sgml -->
+     </para>
     </listitem>
     <listitem>
      <para>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c8f7ab7d956..eff040742d2 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -264,8 +264,8 @@ <title>Description</title>
     <listitem>
      <para>
       This form replaces the expression of a generated column.  Existing data
-      in the column is rewritten and all the future changes will apply the new
-      generation expression.
+      in a stored generated column is rewritten and all the future changes
+      will apply the new generation expression.
      </para>
     </listitem>
    </varlistentry>
@@ -279,10 +279,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index fc81ba3c498..7fe13e6e584 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
 
@@ -281,7 +281,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -290,10 +290,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 70fa929caa4..3bff9c60ebf 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2459,9 +2463,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index a9abaab9056..46c6c2f126f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index cc940742197..773a20ab3f8 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -343,6 +343,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -640,6 +641,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index e817f8f8f84..73b307dd08b 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 024521c66c0..2e0fd67e92d 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -506,7 +506,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -581,6 +581,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
@@ -2545,6 +2556,11 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
+			/* TODO: see transformColumnDefinition() */
+			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("not-null constraints are not supported on virtual generated columns")));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2833,6 +2849,11 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					errmsg("cannot add not-null constraint on system column \"%s\"",
 						   strVal(linitial(constr->keys))));
+		/* TODO: see transformColumnDefinition() */
+		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns")));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 2a7769b1fd1..31926d7d056 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index d6e23caef17..174541f6af0 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1111,6 +1111,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1120,14 +1123,24 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 stmt->isconstraint ?
+					 errmsg("unique constraints on virtual generated columns are not supported") :
+					 errmsg("indexes on virtual generated columns are not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1140,6 +1153,24 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 stmt->isconstraint ?
+						 errmsg("unique constraints on virtual generated columns are not supported") :
+						 errmsg("indexes on virtual generated columns are not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 35747b3df5f..b4914ee5993 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -38,6 +38,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parse_collate.h"
 #include "parser/parse_relation.h"
+#include "rewrite/rewriteHandler.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -687,6 +688,8 @@ TransformPubWhereClauses(List *tables, const char *queryString,
 		/* Fix up collation information */
 		assign_expr_collations(pstate, whereclause);
 
+		whereclause = (Node *) expand_generated_columns_in_expr(whereclause, pri->relation, 1);
+
 		/*
 		 * We allow only simple expressions in row filters. See
 		 * check_simple_rowfilter_expr_walker.
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index a817821bf6d..e24d540cd45 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4181c110eb7..e65cde9c9a5 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3025,6 +3025,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3297,6 +3306,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6098,7 +6116,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7276,7 +7294,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7753,6 +7771,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8379,6 +8405,8 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	HeapTuple	tuple;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
+	char		attgenerated;
+	bool		rewrite;
 	Oid			attrdefoid;
 	ObjectAddress address;
 	Expr	   *defval;
@@ -8393,36 +8421,70 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 						colName, RelationGetRelationName(rel))));
 
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
-	attnum = attTup->attnum;
 
+	attnum = attTup->attnum;
 	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	attgenerated = attTup->attgenerated;
+	if (!attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 						colName, RelationGetRelationName(rel))));
-	ReleaseSysCache(tuple);
 
 	/*
-	 * Clear all the missing values if we're rewriting the table, since this
-	 * renders them pointless.
+	 * TODO: This could be done, just need to recheck any constraints
+	 * afterwards.
 	 */
-	RelationClearMissing(rel);
-
-	/* make sure we don't conflict with later attribute modifications */
-	CommandCounterIncrement();
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Find everything that depends on the column (constraints, indexes, etc),
-	 * and record enough information to let us recreate the objects after
-	 * rewrite.
+	 * We need to prevent this because a change of expression could affect a
+	 * row filter and inject expressions that are not permitted in a row
+	 * filter.  XXX We could try to have a more precise check to catch only
+	 * publications with row filters, or even re-verify the row filter
+	 * expressions.
 	 */
-	RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		GetRelationPublications(RelationGetRelid(rel)) != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
+
+	ReleaseSysCache(tuple);
+
+	if (rewrite)
+	{
+		/*
+		 * Clear all the missing values if we're rewriting the table, since
+		 * this renders them pointless.
+		 */
+		RelationClearMissing(rel);
+
+		/* make sure we don't conflict with later attribute modifications */
+		CommandCounterIncrement();
+
+		/*
+		 * Find everything that depends on the column (constraints, indexes,
+		 * etc), and record enough information to let us recreate the objects
+		 * after rewrite.
+		 */
+		RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	}
 
 	/*
 	 * Drop the dependency records of the GENERATED expression, in particular
@@ -8451,7 +8513,7 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	rawEnt->attnum = attnum;
 	rawEnt->raw_default = newExpr;
 	rawEnt->missingMode = false;
-	rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
+	rawEnt->generated = attgenerated;
 
 	/* Store the generated expression */
 	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
@@ -8460,16 +8522,19 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	/* Make above new expression visible */
 	CommandCounterIncrement();
 
-	/* Prepare for table rewrite */
-	defval = (Expr *) build_column_default(rel, attnum);
+	if (rewrite)
+	{
+		/* Prepare for table rewrite */
+		defval = (Expr *) build_column_default(rel, attnum);
 
-	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
-	newval->attnum = attnum;
-	newval->expr = expression_planner(defval);
-	newval->is_generated = true;
+		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+		newval->attnum = attnum;
+		newval->expr = expression_planner(defval);
+		newval->is_generated = true;
 
-	tab->newvals = lappend(tab->newvals, newval);
-	tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+		tab->newvals = lappend(tab->newvals, newval);
+		tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+	}
 
 	/* Drop any pg_statistic entry for the column */
 	RemoveStatistics(RelationGetRelid(rel), attnum);
@@ -8558,17 +8623,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8711,6 +8789,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9903,6 +9991,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12104,7 +12205,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -13290,8 +13391,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13364,11 +13469,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16354,6 +16460,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18589,8 +18703,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18672,9 +18789,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 32f25f4d911..e19c497bde5 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static HeapTuple check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -2503,6 +2506,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3060,6 +3065,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3490,6 +3497,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6600,3 +6609,37 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and replace the
+ * value with null if so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static HeapTuple
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return tuple;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			if (!heap_attisnull(tuple, i + 1, tupdesc))
+			{
+				int			replCol = i + 1;
+				Datum		replValue = 0;
+				bool		replIsnull = true;
+
+				tuple = heap_modify_tuple_by_cols(tuple, tupdesc, 1, &replCol, &replValue, &replIsnull);
+			}
+		}
+	}
+
+	return tuple;
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index b2c00a0a1b1..0abfb0357dc 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2195,6 +2195,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index a06295b6ba7..c6e84852d4d 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1757,6 +1757,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 			Expr	   *checkconstr;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2304,7 +2305,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index f71899463b8..83d9e25c163 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1354,8 +1354,8 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (relinfo->ri_GeneratedExprsU == NULL)
-		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+	if (!relinfo->ri_Generated_valid)
+		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 1af8c9caf6c..486e4a4882c 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -337,11 +337,14 @@ ExecCheckTIDVisible(EState *estate,
 }
 
 /*
- * Initialize to compute stored generated columns for a tuple
+ * Initialize generated columns handling for a tuple
+ *
+ * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI or
+ * ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
+ * This is used only for stored generated columns.
  *
- * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI
- * or ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
  * If cmdType == CMD_UPDATE, the ri_extraUpdatedCols field is filled too.
+ * This is used by both stored and virtual generated columns.
  *
  * Note: usually, a given query would need only one of ri_GeneratedExprsI and
  * ri_GeneratedExprsU per result rel; but MERGE can need both, and so can
@@ -349,9 +352,9 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-						EState *estate,
-						CmdType cmdtype)
+ExecInitGenerated(ResultRelInfo *resultRelInfo,
+				  EState *estate,
+				  CmdType cmdtype)
 {
 	Relation	rel = resultRelInfo->ri_RelationDesc;
 	TupleDesc	tupdesc = RelationGetDescr(rel);
@@ -362,7 +365,7 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
+	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
 		return;
 
 	/*
@@ -388,7 +391,9 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated)
 		{
 			Expr	   *expr;
 
@@ -413,8 +418,11 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-			ri_NumGeneratedNeeded++;
+			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
+			{
+				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+				ri_NumGeneratedNeeded++;
+			}
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -424,6 +432,13 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		}
 	}
 
+	if (ri_NumGeneratedNeeded == 0)
+	{
+		/* didn't need it after all */
+		pfree(ri_GeneratedExprs);
+		ri_GeneratedExprs = NULL;
+	}
+
 	/* Save in appropriate set of fields */
 	if (cmdtype == CMD_UPDATE)
 	{
@@ -442,6 +457,8 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
+	resultRelInfo->ri_Generated_valid = true;
+
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -472,7 +489,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -480,7 +497,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index b4c1e2c69dd..0c078e3e5bf 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -628,7 +628,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -776,7 +776,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3985,7 +3985,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3993,6 +3993,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4039,6 +4040,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17921,6 +17928,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18575,6 +18583,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 92a04e35dff..5913f5de1ec 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index d2d82c9c596..609cd6d7160 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -986,6 +986,20 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns"),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 2b7499b34b9..2ee48e1b4c0 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1004,7 +1005,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 1a5dfd0aa47..0f21ccf33be 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -980,7 +981,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2203,6 +2205,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2216,10 +2222,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2308,6 +2315,14 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
+																rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4419,6 +4434,96 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+/*
+ * Expand virtual generated columns in an expression
+ *
+ * This is for expressions that are not part of a query, such as default
+ * expressions or index predicates.  The rt_index is usually 1.
+ */
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 3fe74b580a5..728ded52b95 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,6 +592,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -674,6 +676,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 8f73a5df956..1532c27f7c1 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16189,6 +16189,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index bf65d44b942..3b8fb6fe4e8 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3641,12 +3641,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d5543fd62b0..ddd7eb16055 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,6 +2107,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index aee871b0e8f..7b54f8275e7 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -43,6 +43,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 9dea49c52b4..9adc4ba7344 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 557286f0480..3786fb52a2b 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -225,6 +225,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index d1ddc39ad37..bf3b592e28f 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,9 +15,9 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-									EState *estate,
-									CmdType cmdtype);
+extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+							  EState *estate,
+							  CmdType cmdtype);
 
 extern void ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 									   EState *estate, TupleTableSlot *slot,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index b3f7aa299f5..bc2d5b3f16d 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -540,6 +540,9 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
+	/* true if the above have been computed */
+	bool		ri_Generated_valid;
+
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 38d6ad7dcbd..811b80845db 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2765,6 +2765,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 24c22a8694b..ed4ed0793f3 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -490,6 +490,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index d258b26375f..88fe13c5f4f 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index feb6a76b56c..08c8492050e 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index d4f327636fd..b517337d6d8 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2531,6 +2531,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index d091da5a1ef..490ec986b35 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 0d037d48ca0..714eefd38e2 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,9 +1,4 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
- attrelid | attname | attgenerated 
-----------+---------+--------------
-(0 rows)
-
+-- keep these tests aligned with generated_virtual.sql
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -128,6 +123,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -217,6 +230,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -312,6 +346,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -547,7 +585,7 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 ERROR:  permission denied for table gtest11s
@@ -560,7 +598,9 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
  a | c  
 ---+----
  1 | 30
@@ -764,6 +804,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -794,6 +839,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -807,6 +857,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1094,9 +1149,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1190,6 +1245,18 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
@@ -1311,20 +1378,28 @@ BEGIN
   RETURN NEW;
 END;
 $$;
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: new = (1,)
+INFO:  gtest12_03: BEFORE: new = (10,300)
+SELECT * FROM gtest26 ORDER BY a;
+ a  | b  
+----+----
+ 10 | 20
+(1 row)
+
+UPDATE gtest26 SET a = 11 WHERE a = 10;
+INFO:  gtest12_01: BEFORE: old = (10,20)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
+INFO:  gtest12_03: BEFORE: old = (10,20)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1356,3 +1431,9 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+ attrelid | attname | attgenerated 
+----------+---------+--------------
+(0 rows)
+
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 0d037d48ca0..c2fb55894a4 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,10 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
- attrelid | attname | attgenerated 
-----------+---------+--------------
-(0 rows)
-
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+-- keep these tests aligned with generated_stored.sql
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +13,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -128,6 +123,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -153,16 +166,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +210,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +224,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +301,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +324,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,25 +340,44 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -343,28 +390,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -381,8 +428,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -403,7 +450,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -468,7 +515,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -477,7 +524,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -492,7 +539,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -507,11 +554,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -520,7 +567,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -528,30 +575,30 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -560,231 +607,152 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+DETAIL:  Failing row contains (30, virtual).
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+LINE 1: ... b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+                                                             ^
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+DROP TABLE gtest21ax;
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  unique constraints on virtual generated columns are not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -794,6 +762,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -808,32 +781,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -844,103 +822,121 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+  tableoid   |     f1     | f2 | f3 
+-------------+------------+----+----
+ gtest_child | 07-15-2016 |  1 |  2
+ gtest_child | 07-15-2016 |  2 |  4
+(2 rows)
+
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child2 | 08-15-2016 |  3 | 66
+(1 row)
+
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
+ tableoid | f1 | f2 | f3 
+----------+----+----+----
+(0 rows)
+
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 4)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 10)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  8
+ gtest_child2 | 08-15-2016 |  3 | 12
+ gtest_child3 | 09-13-2016 |  1 |  4
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -953,20 +949,20 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
  a | b  
 ---+----
@@ -974,16 +970,16 @@ SELECT * FROM gtest25 ORDER BY a;
  4 | 12
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
 ERROR:  cannot use generated column "b" in column generation expression
 DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
  a | b  | c  |  x  |  d  |  y  
 ---+----+----+-----+-----+-----
@@ -992,15 +988,15 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
+ b      | integer          |           |          | generated always as (a * 3)
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1008,7 +1004,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1016,12 +1012,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1035,20 +1031,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1057,12 +1052,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1074,7 +1069,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1085,18 +1080,18 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1107,93 +1102,114 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 3)
 
 ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
  3 |  9
  4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 5 | 15
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- check that dependencies between columns have also been removed
 ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+ERROR:  cannot drop column a of table gtest29 because other objects depend on it
+DETAIL:  column b of table gtest29 depends on column a of table gtest29
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1246,7 +1262,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1256,12 +1272,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1271,8 +1287,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1300,7 +1316,7 @@ UPDATE gtest26 SET a = 1 WHERE a = 0;
 NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -1311,20 +1327,28 @@ BEGIN
   RETURN NEW;
 END;
 $$;
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: new = (1,)
+INFO:  gtest12_03: BEFORE: new = (10,)
+SELECT * FROM gtest26 ORDER BY a;
+ a  | b  
+----+----
+ 10 | 20
+(1 row)
+
+UPDATE gtest26 SET a = 11 WHERE a = 10;
+INFO:  gtest12_01: BEFORE: old = (10,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
+INFO:  gtest12_03: BEFORE: old = (10,)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1337,22 +1361,28 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+ attrelid | attname | attgenerated 
+----------+---------+--------------
+(0 rows)
 
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index c48f11f2935..7cc405e002d 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -442,7 +442,7 @@ LINE 1: ...ICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
                                                              ^
 DETAIL:  User-defined operators are not allowed.
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 ERROR:  invalid publication WHERE expression
 LINE 1: ...ON testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf...
@@ -523,17 +523,33 @@ Tables:
 Tables from schemas:
     "testpub_rf_schema2"
 
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+ERROR:  invalid publication WHERE expression
+DETAIL:  User-defined or built-in mutable functions are not allowed.
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication
+DETAIL:  Column "y" of relation "testpub_rf_tbl7" is a virtual generated column.
+RESET client_min_messages;
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index fd5654df35e..87929191d06 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index a4c7be487ef..9a820404d3f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -66,6 +66,29 @@ ERROR:  syntax error at or near ","
 LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
                                    ^
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
+DROP TABLE ext_stats_test1;
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
 CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 1edd9e45ebb..7d096c7a294 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 5ee2da4e0e0..a7c7a14031a 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -950,6 +950,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index dea8942c71f..63fd897969a 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..2aeac459445 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,4 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+-- keep these tests aligned with generated_virtual.sql
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -60,6 +59,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -103,6 +104,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -142,6 +151,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 
@@ -278,13 +288,14 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 SELECT a, c FROM gtest11s;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
@@ -390,6 +401,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
@@ -417,6 +432,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,6 +444,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -549,6 +570,18 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
@@ -646,20 +679,21 @@ CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
 END;
 $$;
 
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
 
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
+SELECT * FROM gtest26 ORDER BY a;
+UPDATE gtest26 SET a = 11 WHERE a = 10;
 SELECT * FROM gtest26 ORDER BY a;
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -675,3 +709,7 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 67%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..b5ae20caa7c 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,54 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+-- keep these tests aligned with generated_stored.sql
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -60,6 +59,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -70,7 +71,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +94,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +104,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +143,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +174,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +235,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +250,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +261,179 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+DROP TABLE gtest21ax;
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +441,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -427,6 +454,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -435,6 +465,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
@@ -457,21 +490,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +512,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +526,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +538,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -532,7 +565,7 @@ CREATE TABLE gtest29 (
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +574,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -549,10 +582,22 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -634,7 +679,7 @@ CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
 
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -646,20 +691,21 @@ CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
 END;
 $$;
 
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
 
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
+SELECT * FROM gtest26 ORDER BY a;
+UPDATE gtest26 SET a = 11 WHERE a = 10;
 SELECT * FROM gtest26 ORDER BY a;
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -667,7 +713,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +721,7 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index c4c21a95d0e..3b03fb647f1 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -214,7 +214,7 @@ CREATE FUNCTION testpub_rf_func1(integer, integer) RETURNS boolean AS $$ SELECT
 CREATE OPERATOR =#> (PROCEDURE = testpub_rf_func1, LEFTARG = integer, RIGHTARG = integer);
 CREATE PUBLICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 -- fail - non-immutable functions are not allowed. random() is volatile.
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a < random());
@@ -261,18 +261,30 @@ CREATE PUBLICATION testpub6 FOR TABLES IN SCHEMA testpub_rf_schema2;
 ALTER PUBLICATION testpub6 SET TABLES IN SCHEMA testpub_rf_schema2, TABLE testpub_rf_schema2.testpub_rf_tbl6 WHERE (i < 99);
 RESET client_min_messages;
 \dRp+ testpub6
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+RESET client_min_messages;
 
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index cf09f62eaba..f61dbbf9581 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 5c786b16c6f..75b04e5a136 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -45,6 +45,20 @@ CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
 CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+DROP TABLE ext_stats_test1;
 
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 45587371400..6e73db7b417 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,11 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +57,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +70,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +89,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");
diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl
index e3a6d69da7e..e2c83670053 100644
--- a/src/test/subscription/t/028_row_filter.pl
+++ b/src/test/subscription/t/028_row_filter.pl
@@ -240,6 +240,9 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync PARTITION OF tab_rowfilter_parent_sync FOR VALUES FROM (1) TO (20)"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup structure on subscriber
 $node_subscriber->safe_psql('postgres',
@@ -294,6 +297,9 @@
 	"CREATE TABLE tab_rowfilter_parent_sync (a int)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync (a int)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup logical replication
 $node_publisher->safe_psql('postgres',
@@ -359,6 +365,11 @@
 	"CREATE PUBLICATION tap_pub_child_sync FOR TABLE tab_rowfilter_child_sync WHERE (a < 15)"
 );
 
+# publication using virtual generated column in row filter expression
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_virtual FOR TABLE tab_rowfilter_virtual WHERE (y > 10)"
+);
+
 #
 # The following INSERTs are executed before the CREATE SUBSCRIPTION, so these
 # SQL commands are for testing the initial data copy using logical replication.
@@ -407,8 +418,12 @@
 	"INSERT INTO tab_rowfilter_child(a, b) VALUES(0,'0'),(30,'30'),(40,'40')"
 );
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (1, 2), (2, 4), (3, 6)"
+);
+
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync, tap_pub_virtual"
 );
 
 # wait for initial table synchronization to finish
@@ -550,6 +565,16 @@
 	"SELECT a FROM tab_rowfilter_child_sync ORDER BY 1");
 is($result, qq(), 'check initial data copy from tab_rowfilter_child_sync');
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (1, 2)      NO, 2 * 2 <= 10
+# - INSERT (2, 4)      NO, 4 * 2 <= 10
+# - INSERT (3, 6)      YES, 6 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is($result, qq(3|6),
+	'check initial data copy from table tab_rowfilter_virtual');
+
 # The following commands are executed after CREATE SUBSCRIPTION, so these SQL
 # commands are for testing normal logical replication behavior.
 #
@@ -582,6 +607,8 @@
 	"INSERT INTO tab_rowfilter_child (a, b) VALUES (13, '13'), (17, '17')");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rowfilter_viaroot_part (a) VALUES (14), (15), (16)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (4, 3), (5, 7)");
 
 $node_publisher->wait_for_catchup($appname);
 
@@ -725,6 +752,15 @@
 	'check replicated rows to tab_rowfilter_inherited and tab_rowfilter_child'
 );
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (4, 3)      NO, 3 * 2 <= 10
+# - INSERT (5, 7)      YES, 7 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is( $result, qq(3|6
+5|7), 'check replicated rows to tab_rowfilter_virtual');
+
 # UPDATE the non-toasted column for table tab_rowfilter_toast
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_rowfilter_toast SET b = '1'");

base-commit: 7b27f5fd36cb3270e8ac25aefd73b552663d1392
-- 
2.47.1

From 3d13bc29a263faf10fa56ec9761c912f008439a8 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 9 Jan 2025 20:31:05 +0800
Subject: [PATCH v11 1/1] remove ereport(ERROR, (errcode(...))) unnecessary
 parentheses.

---
 src/backend/catalog/heap.c         | 12 ++---
 src/backend/commands/indexcmds.c   | 16 +++---
 src/backend/commands/statscmds.c   | 12 ++---
 src/backend/commands/tablecmds.c   | 81 +++++++++++++++---------------
 src/backend/parser/parse_utilcmd.c |  7 ++-
 5 files changed, 64 insertions(+), 64 deletions(-)

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 2e0fd67e92..8e77570e6e 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -589,8 +589,8 @@ CheckAttributeType(const char *attname,
 		 */
 		if (flags & CHKATYPE_IS_VIRTUAL)
 			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("virtual generated column \"%s\" cannot have a domain type", attname)));
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
 
 		/*
 		 * If it's a domain, recurse to check its base type.
@@ -2559,8 +2559,8 @@ AddRelationNewConstraints(Relation rel,
 			/* TODO: see transformColumnDefinition() */
 			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
 				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("not-null constraints are not supported on virtual generated columns")));
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("not-null constraints are not supported on virtual generated columns"));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2852,8 +2852,8 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 		/* TODO: see transformColumnDefinition() */
 		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
 			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("not-null constraints are not supported on virtual generated columns")));
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("not-null constraints are not supported on virtual generated columns"));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 174541f6af..fe7952a32f 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1127,10 +1127,10 @@ DefineIndex(Oid tableId,
 
 		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 stmt->isconstraint ?
-					 errmsg("unique constraints on virtual generated columns are not supported") :
-					 errmsg("indexes on virtual generated columns are not supported")));
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					stmt->isconstraint ?
+					errmsg("unique constraints on virtual generated columns are not supported") :
+					errmsg("indexes on virtual generated columns are not supported"));
 	}
 
 	/*
@@ -1166,10 +1166,10 @@ DefineIndex(Oid tableId,
 
 			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 stmt->isconstraint ?
-						 errmsg("unique constraints on virtual generated columns are not supported") :
-						 errmsg("indexes on virtual generated columns are not supported")));
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						stmt->isconstraint ?
+						errmsg("unique constraints on virtual generated columns are not supported") :
+						errmsg("indexes on virtual generated columns are not supported"));
 		}
 	}
 
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index e24d540cd4..a223e0c008 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -249,8 +249,8 @@ CreateStatistics(CreateStatsStmt *stmt)
 			/* Disallow use of virtual generated columns in extended stats */
 			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("statistics creation on virtual generated columns is not supported")));
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("statistics creation on virtual generated columns is not supported"));
 
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
@@ -278,8 +278,8 @@ CreateStatistics(CreateStatsStmt *stmt)
 			/* Disallow use of virtual generated columns in extended stats */
 			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
 				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("statistics creation on virtual generated columns is not supported")));
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("statistics creation on virtual generated columns is not supported"));
 
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
@@ -318,8 +318,8 @@ CreateStatistics(CreateStatsStmt *stmt)
 				/* Disallow use of virtual generated columns in extended stats */
 				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
 					ereport(ERROR,
-							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-							 errmsg("statistics creation on virtual generated columns is not supported")));
+							errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							errmsg("statistics creation on virtual generated columns is not supported"));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index e65cde9c9a..58388ac512 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3027,12 +3027,12 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 
 					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
 						ereport(ERROR,
-								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
-								 errmsg("column \"%s\" inherits from generated column of different kind",
+								errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								errmsg("column \"%s\" inherits from generated column of different kind",
 										restdef->colname),
-								 errdetail("Parent column is %s, child column is %s.",
+								errdetail("Parent column is %s, child column is %s.",
 										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL"));
 
 					/*
 					 * Override the parent's default value for this column
@@ -3308,12 +3308,12 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 
 	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
 		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
-				 errmsg("column \"%s\" inherits from generated column of different kind",
+				errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				errmsg("column \"%s\" inherits from generated column of different kind",
 						inhdef->colname),
-				 errdetail("Parent column is %s, child column is %s.",
+				errdetail("Parent column is %s, child column is %s.",
 						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL"));
 
 	/*
 	 * If new def has a default, override previous default
@@ -7774,10 +7774,10 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 	/* TODO: see transformColumnDefinition() */
 	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("not-null constraints are not supported on virtual generated columns"),
-				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
-						   colName, RelationGetRelationName(rel))));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("not-null constraints are not supported on virtual generated columns"),
+				errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel)));
 
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
@@ -8432,9 +8432,9 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	attgenerated = attTup->attgenerated;
 	if (!attgenerated)
 		ereport(ERROR,
-				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
-						colName, RelationGetRelationName(rel))));
+				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				errmsg("column \"%s\" of relation \"%s\" is not a generated column",
+						colName, RelationGetRelationName(rel)));
 
 	/*
 	 * TODO: This could be done, just need to recheck any constraints
@@ -8443,10 +8443,10 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
 		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
-				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
-						   colName, RelationGetRelationName(rel))));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel)));
 
 	/*
 	 * We need to prevent this because a change of expression could affect a
@@ -8458,10 +8458,10 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
 		GetRelationPublications(RelationGetRelid(rel)) != NIL)
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
-				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
-						   colName, RelationGetRelationName(rel))));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel)));
 
 	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
 
@@ -8631,18 +8631,18 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 	 */
 	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
-				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
-						   colName, RelationGetRelationName(rel))));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel)));
 
 	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
-					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
-							colName, RelationGetRelationName(rel))));
+					errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+					errmsg("column \"%s\" of relation \"%s\" is not a generated column",
+							colName, RelationGetRelationName(rel)));
 		else
 		{
 			ereport(NOTICE,
@@ -8795,9 +8795,9 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 	 */
 	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
-						colName)));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName));
 
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
@@ -10002,8 +10002,8 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 */
 		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("foreign key constraints on virtual generated columns are not supported")));
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("foreign key constraints on virtual generated columns are not supported"));
 	}
 
 	/*
@@ -16456,17 +16456,18 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must be a generated column", parent_attname)));
 			if (child_att->attgenerated && !parent_att->attgenerated)
-				ereport(ERROR,
+	ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),				ereport(ERROR,
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
 			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
 				ereport(ERROR,
-						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
-						 errdetail("Parent column is %s, child column is %s.",
+						errcode(ERRCODE_DATATYPE_MISMATCH),
+						errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						errdetail("Parent column is %s, child column is %s.",
 								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
-								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL"));
 
 			/*
 			 * Regular inheritance children are independent enough not to
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 609cd6d716..0328c8784e 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -996,10 +996,9 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 		 */
 		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
 			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("not-null constraints are not supported on virtual generated columns"),
-					 parser_errposition(cxt->pstate,
-										constraint->location)));
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("not-null constraints are not supported on virtual generated columns"),
+					parser_errposition(cxt->pstate, constraint->location));
 	}
 
 	/*
-- 
2.34.1

From 3ae0b17a06ac5632564ccca7db254e9d822a916f Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 14 Jan 2025 11:25:20 +0100
Subject: [PATCH v12 1/2] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

The syntax for the column definition is

    ... GENERATED ALWAYS AS (...) VIRTUAL

and VIRTUAL is also optional.  VIRTUAL is the default rather than
STORED to match various other SQL products.  (The SQL standard makes
no specification about this, but it also doesn't know about VIRTUAL or
STORED.)  (Also, virtual views are the default, rather than
materialized views.)

Virtual generated columns are stored in tuples as null values.  (A
very early version of this patch had the ambition to not store them at
all.  But so much stuff breaks or gets confused if you have tuples
where a column in the middle is completely missing.  This is a
compromise, and it still saves space over being forced to use stored
generated columns.  If we ever find a way to improve this, a bit of
pg_upgrade cleverness could allow for upgrades to a newer scheme.)

The capabilities and restrictions of virtual generated columns are
mostly the same as for stored generated columns.  In some cases, this
patch keeps virtual generated columns more restricted than they might
technically need to be, to keep the two kinds consistent.  Some of
that could maybe be relaxed later after separate careful
considerations.

Some functionality that is currently not supported, but could possibly
be added as incremental features, some easier than others:

- index on or using a virtual column
- hence also no unique constraints on virtual columns
- extended statistics on virtual columns
- foreign key constraints on virtual columns
- not-null constraints on virtual columns (check constraints are supported)
- ALTER TABLE / DROP EXPRESSION
- virtual column cannot have domain type

The tests in generated_virtual.sql have been copied over from
generated_stored.sql with the keyword replaced.  This way we can make
sure the behavior is mostly aligned, and the differences can be
visible.  Some tests for currently not supported features are
currently commented out.

TODO:
- handling of publication option publish_generated_columns
- catversion

contributions by Jian He, Dean Rasheed

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   6 +-
 doc/src/sgml/ddl.sgml                         |  45 +-
 doc/src/sgml/ref/alter_table.sgml             |  15 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  23 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  33 +-
 src/backend/commands/publicationcmds.c        |   3 +
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 196 +++-
 src/backend/commands/trigger.c                |  45 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/executor/execUtils.c              |   4 +-
 src/backend/executor/nodeModifyTable.c        |  41 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  16 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 118 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/executor/nodeModifyTable.h        |   6 +-
 src/include/nodes/execnodes.h                 |   3 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     | 120 ++-
 ...rated_stored.out => generated_virtual.out} | 864 +++++++++---------
 src/test/regress/expected/publication.out     |  18 +-
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/expected/stats_ext.out       |  23 +
 src/test/regress/parallel_schedule            |   3 +
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  60 +-
 ...rated_stored.sql => generated_virtual.sql} | 348 ++++---
 src/test/regress/sql/publication.sql          |  14 +-
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/regress/sql/stats_ext.sql            |  14 +
 src/test/subscription/t/011_generated.pl      |  39 +-
 src/test/subscription/t/028_row_filter.pl     |  38 +-
 68 files changed, 1771 insertions(+), 784 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (67%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (66%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index bf322198a20..32d581e8422 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7283,65 +7283,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7349,28 +7352,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 3900522ccb5..71a27282138 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1836,12 +1836,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 238ed679190..cc5104d1d5f 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1307,8 +1307,10 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.  A stored generated column is physically stored like a normal
+       column.  A virtual generated column is physically stored as a null
+       value, with the actual value being computed at run time.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index dea04d64db6..502dd154645 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
@@ -502,6 +507,26 @@ <title>Generated Columns</title>
       particular role can read from a generated column but not from the
       underlying base columns.
      </para>
+
+     <para>
+      For virtual generated columns, this is only fully secure if the
+      generation expression uses only leakproof functions (see <xref
+      linkend="sql-createfunction"/>), but this is not enforced by the system.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Privileges of functions used in generation expressions are checked when
+      the expression is actually executed, on write or read respectively, as
+      if the generation expression had been called directly from the query
+      using the generated column.  The user of a generated column must have
+      permissions to call all functions used by the generation expression.
+      Functions in the generation expression are executed with the privileges
+      of the user executing the query or the function owner, depending on
+      whether the functions are defined as <literal>SECURITY INVOKER</literal>
+      or <literal>SECURITY DEFINER</literal>.
+      <!-- matches create_view.sgml -->
+     </para>
     </listitem>
     <listitem>
      <para>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 938450fba18..29c513f76da 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -264,8 +264,8 @@ <title>Description</title>
     <listitem>
      <para>
       This form replaces the expression of a generated column.  Existing data
-      in the column is rewritten and all the future changes will apply the new
-      generation expression.
+      in a stored generated column is rewritten and all the future changes
+      will apply the new generation expression.
      </para>
     </listitem>
    </varlistentry>
@@ -279,10 +279,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index 0dcd9ca6f87..e0b0e075c2c 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 [ ENFORCED | NOT ENFORCED ]
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
@@ -283,7 +283,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -292,10 +292,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 2237321cb4f..060793404f1 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2489,9 +2493,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index a9abaab9056..46c6c2f126f 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -289,6 +289,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index fe197447912..ed2195f14b2 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -342,6 +342,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -640,6 +641,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index e817f8f8f84..73b307dd08b 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 57ef466acce..956f196fc95 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -507,7 +507,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -582,6 +582,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
@@ -2553,6 +2564,11 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
+			/* TODO: see transformColumnDefinition() */
+			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("not-null constraints are not supported on virtual generated columns"));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2868,6 +2884,11 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					errmsg("cannot add not-null constraint on system column \"%s\"",
 						   strVal(linitial(constr->keys))));
+		/* TODO: see transformColumnDefinition() */
+		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("not-null constraints are not supported on virtual generated columns"));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 2a7769b1fd1..31926d7d056 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index d6e23caef17..174541f6af0 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1111,6 +1111,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1120,14 +1123,24 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 stmt->isconstraint ?
+					 errmsg("unique constraints on virtual generated columns are not supported") :
+					 errmsg("indexes on virtual generated columns are not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1140,6 +1153,24 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 stmt->isconstraint ?
+						 errmsg("unique constraints on virtual generated columns are not supported") :
+						 errmsg("indexes on virtual generated columns are not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 35747b3df5f..b4914ee5993 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -38,6 +38,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parse_collate.h"
 #include "parser/parse_relation.h"
+#include "rewrite/rewriteHandler.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -687,6 +688,8 @@ TransformPubWhereClauses(List *tables, const char *queryString,
 		/* Fix up collation information */
 		assign_expr_collations(pstate, whereclause);
 
+		whereclause = (Node *) expand_generated_columns_in_expr(whereclause, pri->relation, 1);
+
 		/*
 		 * We allow only simple expressions in row filters. See
 		 * check_simple_rowfilter_expr_walker.
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index a817821bf6d..e24d540cd45 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 4fc54bd6eba..22541941b43 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3027,6 +3027,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3312,6 +3321,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6118,7 +6136,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7296,7 +7314,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7773,6 +7791,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8399,6 +8425,8 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	HeapTuple	tuple;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
+	char		attgenerated;
+	bool		rewrite;
 	Oid			attrdefoid;
 	ObjectAddress address;
 	Expr	   *defval;
@@ -8413,36 +8441,70 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 						colName, RelationGetRelationName(rel))));
 
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
-	attnum = attTup->attnum;
 
+	attnum = attTup->attnum;
 	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	attgenerated = attTup->attgenerated;
+	if (!attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 						colName, RelationGetRelationName(rel))));
-	ReleaseSysCache(tuple);
 
 	/*
-	 * Clear all the missing values if we're rewriting the table, since this
-	 * renders them pointless.
+	 * TODO: This could be done, just need to recheck any constraints
+	 * afterwards.
 	 */
-	RelationClearMissing(rel);
-
-	/* make sure we don't conflict with later attribute modifications */
-	CommandCounterIncrement();
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Find everything that depends on the column (constraints, indexes, etc),
-	 * and record enough information to let us recreate the objects after
-	 * rewrite.
+	 * We need to prevent this because a change of expression could affect a
+	 * row filter and inject expressions that are not permitted in a row
+	 * filter.  XXX We could try to have a more precise check to catch only
+	 * publications with row filters, or even re-verify the row filter
+	 * expressions.
 	 */
-	RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		GetRelationPublications(RelationGetRelid(rel)) != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
+
+	ReleaseSysCache(tuple);
+
+	if (rewrite)
+	{
+		/*
+		 * Clear all the missing values if we're rewriting the table, since
+		 * this renders them pointless.
+		 */
+		RelationClearMissing(rel);
+
+		/* make sure we don't conflict with later attribute modifications */
+		CommandCounterIncrement();
+
+		/*
+		 * Find everything that depends on the column (constraints, indexes,
+		 * etc), and record enough information to let us recreate the objects
+		 * after rewrite.
+		 */
+		RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	}
 
 	/*
 	 * Drop the dependency records of the GENERATED expression, in particular
@@ -8471,7 +8533,7 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	rawEnt->attnum = attnum;
 	rawEnt->raw_default = newExpr;
 	rawEnt->missingMode = false;
-	rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
+	rawEnt->generated = attgenerated;
 
 	/* Store the generated expression */
 	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
@@ -8480,16 +8542,19 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	/* Make above new expression visible */
 	CommandCounterIncrement();
 
-	/* Prepare for table rewrite */
-	defval = (Expr *) build_column_default(rel, attnum);
+	if (rewrite)
+	{
+		/* Prepare for table rewrite */
+		defval = (Expr *) build_column_default(rel, attnum);
 
-	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
-	newval->attnum = attnum;
-	newval->expr = expression_planner(defval);
-	newval->is_generated = true;
+		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+		newval->attnum = attnum;
+		newval->expr = expression_planner(defval);
+		newval->is_generated = true;
 
-	tab->newvals = lappend(tab->newvals, newval);
-	tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+		tab->newvals = lappend(tab->newvals, newval);
+		tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+	}
 
 	/* Drop any pg_statistic entry for the column */
 	RemoveStatistics(RelationGetRelid(rel), attnum);
@@ -8578,17 +8643,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8731,6 +8809,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9923,6 +10011,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12130,7 +12231,7 @@ ATExecValidateConstraint(List **wqueue, Relation rel, char *constrName,
 			val = SysCacheGetAttrNotNull(CONSTROID, tuple,
 										 Anum_pg_constraint_conbin);
 			conbin = TextDatumGetCString(val);
-			newcon->qual = (Node *) stringToNode(conbin);
+			newcon->qual = (Node *) expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 			/* Find or create work queue entry for this table */
 			tab = ATGetQueueEntry(wqueue, rel);
@@ -13316,8 +13417,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13390,11 +13495,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16383,6 +16489,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18630,8 +18744,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18713,9 +18830,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index acf3e4a3f1f..b0e35f65a0e 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static HeapTuple check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -2504,6 +2507,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3061,6 +3066,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3491,6 +3498,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = (Node *) expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6601,3 +6610,37 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and replace the
+ * value with null if so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static HeapTuple
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return tuple;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			if (!heap_attisnull(tuple, i + 1, tupdesc))
+			{
+				int			replCol = i + 1;
+				Datum		replValue = 0;
+				bool		replIsnull = true;
+
+				tuple = heap_modify_tuple_by_cols(tuple, tupdesc, 1, &replCol, &replValue, &replIsnull);
+			}
+		}
+	}
+
+	return tuple;
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index b2c00a0a1b1..0abfb0357dc 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2195,6 +2195,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2d28ec65fc4..82d51bb9aff 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1761,6 +1761,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 				continue;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2308,7 +2309,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index f71899463b8..83d9e25c163 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1354,8 +1354,8 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (relinfo->ri_GeneratedExprsU == NULL)
-		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+	if (!relinfo->ri_Generated_valid)
+		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 1af8c9caf6c..486e4a4882c 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -337,11 +337,14 @@ ExecCheckTIDVisible(EState *estate,
 }
 
 /*
- * Initialize to compute stored generated columns for a tuple
+ * Initialize generated columns handling for a tuple
+ *
+ * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI or
+ * ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
+ * This is used only for stored generated columns.
  *
- * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI
- * or ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
  * If cmdType == CMD_UPDATE, the ri_extraUpdatedCols field is filled too.
+ * This is used by both stored and virtual generated columns.
  *
  * Note: usually, a given query would need only one of ri_GeneratedExprsI and
  * ri_GeneratedExprsU per result rel; but MERGE can need both, and so can
@@ -349,9 +352,9 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-						EState *estate,
-						CmdType cmdtype)
+ExecInitGenerated(ResultRelInfo *resultRelInfo,
+				  EState *estate,
+				  CmdType cmdtype)
 {
 	Relation	rel = resultRelInfo->ri_RelationDesc;
 	TupleDesc	tupdesc = RelationGetDescr(rel);
@@ -362,7 +365,7 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
+	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
 		return;
 
 	/*
@@ -388,7 +391,9 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated)
 		{
 			Expr	   *expr;
 
@@ -413,8 +418,11 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-			ri_NumGeneratedNeeded++;
+			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
+			{
+				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+				ri_NumGeneratedNeeded++;
+			}
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -424,6 +432,13 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		}
 	}
 
+	if (ri_NumGeneratedNeeded == 0)
+	{
+		/* didn't need it after all */
+		pfree(ri_GeneratedExprs);
+		ri_GeneratedExprs = NULL;
+	}
+
 	/* Save in appropriate set of fields */
 	if (cmdtype == CMD_UPDATE)
 	{
@@ -442,6 +457,8 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
+	resultRelInfo->ri_Generated_valid = true;
+
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -472,7 +489,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -480,7 +497,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 6079de70e09..fe4a5d718cb 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -630,7 +630,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -778,7 +778,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3989,7 +3989,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -3997,6 +3997,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4044,6 +4045,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17947,6 +17954,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18602,6 +18610,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 92a04e35dff..5913f5de1ec 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -704,7 +704,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ca028d2a66d..eb7716cd84c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -988,6 +988,20 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns"),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 2b7499b34b9..2ee48e1b4c0 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1004,7 +1005,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 1a5dfd0aa47..023d77046bb 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,7 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
 
 
 /*
@@ -980,7 +981,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2203,6 +2205,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2216,10 +2222,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2308,6 +2315,14 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
+																rel, rt_index, rte);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4419,6 +4434,99 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+	}
+
+	return node;
+}
+
+/*
+ * Expand virtual generated columns in an expression
+ *
+ * This is for expressions that are not part of a query, such as default
+ * expressions or index predicates.  The rt_index is usually 1.
+ */
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		/* eref needs to be set, but the actual name doesn't matter */
+		rte->eref = makeAlias(RelationGetRelationName(rel), NIL);
+		rte->rtekind = RTE_RELATION;
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 43219a9629c..398114373e9 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,6 +592,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -674,6 +676,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 8f73a5df956..1532c27f7c1 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16189,6 +16189,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index bf65d44b942..3b8fb6fe4e8 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3641,12 +3641,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index d5543fd62b0..ddd7eb16055 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2107,6 +2107,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index ff27df9e9a6..396eeb7a0bb 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -44,6 +44,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index cad830dc39c..19c594458bd 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 557286f0480..3786fb52a2b 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -225,6 +225,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index d1ddc39ad37..bf3b592e28f 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,9 +15,9 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-									EState *estate,
-									CmdType cmdtype);
+extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+							  EState *estate,
+							  CmdType cmdtype);
 
 extern void ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 									   EState *estate, TupleTableSlot *slot,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index b3f7aa299f5..bc2d5b3f16d 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -540,6 +540,9 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
+	/* true if the above have been computed */
+	bool		ri_Generated_valid;
+
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index b191eaaecab..de17b21299a 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2768,6 +2768,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index cf2917ad07e..40cf090ce61 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -491,6 +491,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index d258b26375f..88fe13c5f4f 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index feb6a76b56c..08c8492050e 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index d4f327636fd..b517337d6d8 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2531,6 +2531,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index e0613891351..2cebe382432 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 0d037d48ca0..77242838b26 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,9 +1,4 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
- attrelid | attname | attgenerated 
-----------+---------+--------------
-(0 rows)
-
+-- keep these tests aligned with generated_virtual.sql
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -128,6 +123,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -217,6 +230,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -312,6 +346,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -547,7 +585,7 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 ERROR:  permission denied for table gtest11s
@@ -560,7 +598,9 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
  a | c  
 ---+----
  1 | 30
@@ -595,6 +635,13 @@ INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
+-- check with whole-row reference
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
+INSERT INTO gtest20c VALUES (1);  -- ok
+INSERT INTO gtest20c VALUES (NULL);  -- fails
+ERROR:  new row for relation "gtest20c" violates check constraint "whole_row_check"
+DETAIL:  Failing row contains (null, null).
 -- not-null constraints
 CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
 INSERT INTO gtest21a (a) VALUES (1);  -- ok
@@ -764,6 +811,11 @@ CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a *
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
 ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
+ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
 CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
@@ -794,6 +846,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -807,6 +864,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1094,9 +1156,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1190,6 +1252,18 @@ Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
@@ -1311,20 +1385,28 @@ BEGIN
   RETURN NEW;
 END;
 $$;
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: new = (1,)
+INFO:  gtest12_03: BEFORE: new = (10,300)
+SELECT * FROM gtest26 ORDER BY a;
+ a  | b  
+----+----
+ 10 | 20
+(1 row)
+
+UPDATE gtest26 SET a = 11 WHERE a = 10;
+INFO:  gtest12_01: BEFORE: old = (10,20)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
+INFO:  gtest12_03: BEFORE: old = (10,20)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1356,3 +1438,9 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
  c      | integer |           |          | 
  x      | integer |           |          | generated always as (b * 2) stored
 
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+ attrelid | attname | attgenerated 
+----------+---------+--------------
+(0 rows)
+
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 67%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 0d037d48ca0..5a74c0a0947 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,15 +1,10 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
- attrelid | attname | attgenerated 
-----------+---------+--------------
-(0 rows)
-
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+-- keep these tests aligned with generated_stored.sql
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -18,89 +13,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -128,6 +123,24 @@ SELECT * FROM gtest1 ORDER BY a;
  4 | 8
 (4 rows)
 
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+ gtest1 
+--------
+ (1,2)
+ (2,4)
+ (3,6)
+ (4,8)
+(4 rows)
+
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
+ a | b 
+---+---
+ 1 | 2
+ 2 | 4
+ 3 | 6
+ 4 | 8
+(4 rows)
+
 DELETE FROM gtest1 WHERE a >= 3;
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
 UPDATE gtest1 SET b = 11 WHERE a = 1;  -- error
@@ -153,16 +166,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -203,8 +210,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -217,6 +224,27 @@ SELECT * FROM gtestm ORDER BY id;
   2 | 20 | 200 | 40 | 400
 (2 rows)
 
+DROP TABLE gtestm;
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+ a  | b  | a  | b  
+----+----+----+----
+  1 |  2 |  1 |  2
+  2 |  4 |  2 |  4
+  3 |  6 |  3 |  6
+  4 |  8 |  4 |  8
+  5 | 10 |  5 | 10
+  6 | 12 |  6 | 12
+  7 | 14 |  7 | 14
+  8 | 16 |  8 | 16
+  9 | 18 |  9 | 18
+ 10 | 20 | 10 | 20
+(10 rows)
+
 DROP TABLE gtestm;
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
@@ -273,11 +301,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -296,12 +324,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -312,25 +340,44 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
+(3 rows)
+
+SELECT * FROM gtestx;
+ a  |  b  | x  
+----+-----+----
+ 11 | 242 | 22
+(1 row)
+
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -343,28 +390,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -381,8 +428,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -403,7 +450,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -468,7 +515,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -477,7 +524,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -492,7 +539,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -507,11 +554,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -520,7 +567,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -528,30 +575,30 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-ERROR:  permission denied for table gtest11s
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+ERROR:  permission denied for table gtest11v
+SELECT a, c FROM gtest11v;  -- allowed
  a | c  
 ---+----
  1 | 20
@@ -560,231 +607,159 @@ SELECT a, c FROM gtest11s;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12s;  -- allowed
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
+ERROR:  permission denied for function gf1
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
-DETAIL:  column c of table gtest12s depends on function gf1(integer)
+DETAIL:  column c of table gtest12v depends on function gf1(integer)
 HINT:  Use DROP ... CASCADE to drop the dependent objects too.
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+DETAIL:  Failing row contains (30, virtual).
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- check with whole-row reference
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
+INSERT INTO gtest20c VALUES (1);  -- ok
+INSERT INTO gtest20c VALUES (NULL);  -- fails
+ERROR:  new row for relation "gtest20c" violates check constraint "whole_row_check"
+DETAIL:  Failing row contains (null, virtual).
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+LINE 1: ... b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+                                                             ^
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+DROP TABLE gtest21ax;
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  unique constraints on virtual generated columns are not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -794,6 +769,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -808,32 +788,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -844,103 +829,121 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+  tableoid   |     f1     | f2 | f3 
+-------------+------------+----+----
+ gtest_child | 07-15-2016 |  1 |  2
+ gtest_child | 07-15-2016 |  2 |  4
+(2 rows)
+
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+   tableoid   |     f1     | f2 | f3 
+--------------+------------+----+----
+ gtest_child2 | 08-15-2016 |  3 | 66
+(1 row)
+
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
+ tableoid | f1 | f2 | f3 
+----------+----+----+----
+(0 rows)
+
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 4)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 10)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  8
+ gtest_child2 | 08-15-2016 |  3 | 12
+ gtest_child3 | 09-13-2016 |  1 |  4
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -953,20 +956,20 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
  a | b  
 ---+----
@@ -974,16 +977,16 @@ SELECT * FROM gtest25 ORDER BY a;
  4 | 12
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
 ERROR:  cannot use generated column "b" in column generation expression
 DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
  a | b  | c  |  x  |  d  |  y  
 ---+----+----+-----+-----+-----
@@ -992,15 +995,15 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
+ b      | integer          |           |          | generated always as (a * 3)
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1008,7 +1011,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1016,12 +1019,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1035,20 +1038,19 @@ ERROR:  cannot specify USING when altering type of generated column
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1057,12 +1059,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1074,7 +1076,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1085,18 +1087,18 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1107,93 +1109,105 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 3)
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
  3 |  9
  4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 5 | 15
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
-
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
+DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1246,7 +1260,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1256,12 +1270,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1271,8 +1285,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1300,7 +1314,7 @@ UPDATE gtest26 SET a = 1 WHERE a = 0;
 NOTICE:  OK
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -1311,20 +1325,28 @@ BEGIN
   RETURN NEW;
 END;
 $$;
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
-INFO:  gtest12_01: BEFORE: old = (1,2)
+INFO:  gtest12_01: BEFORE: new = (1,)
+INFO:  gtest12_03: BEFORE: new = (10,)
+SELECT * FROM gtest26 ORDER BY a;
+ a  | b  
+----+----
+ 10 | 20
+(1 row)
+
+UPDATE gtest26 SET a = 11 WHERE a = 10;
+INFO:  gtest12_01: BEFORE: old = (10,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (1,2)
+INFO:  gtest12_03: BEFORE: old = (10,)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1337,22 +1359,28 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+ attrelid | attname | attgenerated 
+----------+---------+--------------
+(0 rows)
 
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index c48f11f2935..7cc405e002d 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -442,7 +442,7 @@ LINE 1: ...ICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
                                                              ^
 DETAIL:  User-defined operators are not allowed.
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 ERROR:  invalid publication WHERE expression
 LINE 1: ...ON testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf...
@@ -523,17 +523,33 @@ Tables:
 Tables from schemas:
     "testpub_rf_schema2"
 
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+ERROR:  invalid publication WHERE expression
+DETAIL:  User-defined or built-in mutable functions are not allowed.
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication
+DETAIL:  Column "y" of relation "testpub_rf_tbl7" is a virtual generated column.
+RESET client_min_messages;
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index fd5654df35e..87929191d06 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index a4c7be487ef..9a820404d3f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -66,6 +66,29 @@ ERROR:  syntax error at or near ","
 LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
                                    ^
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
+DROP TABLE ext_stats_test1;
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
 CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 1edd9e45ebb..7d096c7a294 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -68,6 +68,9 @@ test: select_into select_distinct select_distinct_on select_implicit select_havi
 # ----------
 test: brin gin gist spgist privileges init_privs security_label collate matview lock replica_identity rowsecurity object_address tablesample groupingsets drop_operator password identity generated_stored join_hash
 
+# TODO: find a place for this (above group is full)
+test: generated_virtual
+
 # ----------
 # Additional BRIN tests
 # ----------
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index 5ee2da4e0e0..a7c7a14031a 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -950,6 +950,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index a41f8b83d77..63a60303659 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index c18e0e1f655..77c13306a58 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,5 +1,4 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+-- keep these tests aligned with generated_virtual.sql
 
 
 CREATE SCHEMA generated_stored_tests;
@@ -60,6 +59,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -103,6 +104,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) STORED
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -142,6 +151,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 
@@ -278,13 +288,14 @@ CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE
 
 CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
 INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+GRANT SELECT (a, c), INSERT ON gtest12s TO regress_user11;
 
 SET ROLE regress_user11;
 SELECT a, b FROM gtest11s;  -- not allowed
 SELECT a, c FROM gtest11s;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12s VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+SELECT a, c FROM gtest12s;  -- allowed (does not actually invoke the function)
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
@@ -311,6 +322,12 @@ CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
+-- check with whole-row reference
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
+INSERT INTO gtest20c VALUES (1);  -- ok
+INSERT INTO gtest20c VALUES (NULL);  -- fails
+
 -- not-null constraints
 CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
 INSERT INTO gtest21a (a) VALUES (1);  -- ok
@@ -390,6 +407,10 @@ CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
 CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
 INSERT INTO gtest24 (a) VALUES (4);  -- ok
 INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
+INSERT INTO gtest24r (a) VALUES (4);  -- ok
+INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
@@ -417,6 +438,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -426,6 +450,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -549,6 +576,18 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
@@ -646,20 +685,21 @@ CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
 END;
 $$;
 
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
 
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
+SELECT * FROM gtest26 ORDER BY a;
+UPDATE gtest26 SET a = 11 WHERE a = 10;
 SELECT * FROM gtest26 ORDER BY a;
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -675,3 +715,7 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 66%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index c18e0e1f655..f855898caa8 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,55 +1,54 @@
--- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+-- keep these tests aligned with generated_stored.sql
 
 
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -60,6 +59,8 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 INSERT INTO gtest1 VALUES (3, DEFAULT), (4, DEFAULT);  -- ok
 
 SELECT * FROM gtest1 ORDER BY a;
+SELECT gtest1 FROM gtest1 ORDER BY a;  -- whole-row reference
+SELECT a, (SELECT gtest1.b) FROM gtest1 ORDER BY a;  -- sublink
 DELETE FROM gtest1 WHERE a >= 3;
 
 UPDATE gtest1 SET b = DEFAULT WHERE a = 1;
@@ -70,7 +71,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -93,8 +94,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -103,6 +104,14 @@ CREATE TABLE gtestm (
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 
+CREATE TABLE gtestm (
+  a int PRIMARY KEY,
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
+);
+INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
+MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
+DROP TABLE gtestm;
+
 -- views
 CREATE VIEW gtest1v AS SELECT * FROM gtest1;
 SELECT * FROM gtest1v;
@@ -134,22 +143,26 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
+INSERT INTO gtestx (a, x) VALUES (11, 22);
+SELECT * FROM gtest1;
+SELECT * FROM gtestx;
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -161,28 +174,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update XXX
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -222,12 +235,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -237,7 +250,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -248,168 +261,185 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
-INSERT INTO gtest11s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest11s TO regress_user11;
+CREATE TABLE gtest11v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+INSERT INTO gtest11v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c) ON gtest11v TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12s (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
-INSERT INTO gtest12s VALUES (1, 10), (2, 20);
-GRANT SELECT (a, c) ON gtest12s TO regress_user11;
+CREATE TABLE gtest12v (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
+INSERT INTO gtest12v VALUES (1, 10), (2, 20);
+GRANT SELECT (a, c), INSERT ON gtest12v TO regress_user11;
 
 SET ROLE regress_user11;
-SELECT a, b FROM gtest11s;  -- not allowed
-SELECT a, c FROM gtest11s;  -- allowed
+SELECT a, b FROM gtest11v;  -- not allowed
+SELECT a, c FROM gtest11v;  -- allowed
 SELECT gf1(10);  -- not allowed
-SELECT a, c FROM gtest12s;  -- allowed
+INSERT INTO gtest12v VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12v;  -- currently not allowed because of function permissions, should arguably be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
-DROP TABLE gtest11s, gtest12s;
+DROP TABLE gtest11v, gtest12v;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- check with whole-row reference
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
+INSERT INTO gtest20c VALUES (1);  -- ok
+INSERT INTO gtest20c VALUES (NULL);  -- fails
+
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+DROP TABLE gtest21ax;
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -417,6 +447,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -427,6 +460,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -435,6 +471,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
+SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
@@ -457,21 +496,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -479,7 +518,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -493,7 +532,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -505,7 +544,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -519,20 +558,20 @@ CREATE TABLE gtest29 (
 SELECT * FROM gtest29;
 \d gtest29
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
 SELECT * FROM gtest29;
 \d gtest29
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -541,7 +580,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -549,10 +588,22 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 \d gtest30_1
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
+-- composite type dependencies
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
+-- Check it for a partitioned table, too
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_2 (x int, y gtest31_1);
+ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
+DROP TABLE gtest31_1, gtest31_2;
+
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -634,7 +685,7 @@ CREATE TRIGGER gtest11 BEFORE UPDATE OF b ON gtest26
 DROP TRIGGER gtest11 ON gtest26;
 TRUNCATE gtest26;
 
--- check that modifications of stored generated columns in triggers do
+-- check that modifications of generated columns in triggers do
 -- not get propagated
 CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
   LANGUAGE plpgsql
@@ -646,20 +697,21 @@ CREATE FUNCTION gtest_trigger_func4() RETURNS trigger
 END;
 $$;
 
-CREATE TRIGGER gtest12_01 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_01 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
-CREATE TRIGGER gtest12_02 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_02 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func4();
 
-CREATE TRIGGER gtest12_03 BEFORE UPDATE ON gtest26
+CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   FOR EACH ROW
   EXECUTE PROCEDURE gtest_trigger_func();
 
 INSERT INTO gtest26 (a) VALUES (1);
-UPDATE gtest26 SET a = 11 WHERE a = 1;
+SELECT * FROM gtest26 ORDER BY a;
+UPDATE gtest26 SET a = 11 WHERE a = 10;
 SELECT * FROM gtest26 ORDER BY a;
 
 -- LIKE INCLUDING GENERATED and dropped column handling
@@ -667,7 +719,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -675,3 +727,7 @@ CREATE TABLE gtest28a (
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 \d gtest28*
+
+
+-- sanity check of system catalog
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index c4c21a95d0e..3b03fb647f1 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -214,7 +214,7 @@ CREATE FUNCTION testpub_rf_func1(integer, integer) RETURNS boolean AS $$ SELECT
 CREATE OPERATOR =#> (PROCEDURE = testpub_rf_func1, LEFTARG = integer, RIGHTARG = integer);
 CREATE PUBLICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 -- fail - non-immutable functions are not allowed. random() is volatile.
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a < random());
@@ -261,18 +261,30 @@ CREATE PUBLICATION testpub6 FOR TABLES IN SCHEMA testpub_rf_schema2;
 ALTER PUBLICATION testpub6 SET TABLES IN SCHEMA testpub_rf_schema2, TABLE testpub_rf_schema2.testpub_rf_tbl6 WHERE (i < 99);
 RESET client_min_messages;
 \dRp+ testpub6
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+RESET client_min_messages;
 
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index cf09f62eaba..f61dbbf9581 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 5c786b16c6f..75b04e5a136 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -45,6 +45,20 @@ CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
 CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+DROP TABLE ext_stats_test1;
 
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 45587371400..6e73db7b417 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,11 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +57,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +70,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +89,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");
diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl
index e3a6d69da7e..e2c83670053 100644
--- a/src/test/subscription/t/028_row_filter.pl
+++ b/src/test/subscription/t/028_row_filter.pl
@@ -240,6 +240,9 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync PARTITION OF tab_rowfilter_parent_sync FOR VALUES FROM (1) TO (20)"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup structure on subscriber
 $node_subscriber->safe_psql('postgres',
@@ -294,6 +297,9 @@
 	"CREATE TABLE tab_rowfilter_parent_sync (a int)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync (a int)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup logical replication
 $node_publisher->safe_psql('postgres',
@@ -359,6 +365,11 @@
 	"CREATE PUBLICATION tap_pub_child_sync FOR TABLE tab_rowfilter_child_sync WHERE (a < 15)"
 );
 
+# publication using virtual generated column in row filter expression
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_virtual FOR TABLE tab_rowfilter_virtual WHERE (y > 10)"
+);
+
 #
 # The following INSERTs are executed before the CREATE SUBSCRIPTION, so these
 # SQL commands are for testing the initial data copy using logical replication.
@@ -407,8 +418,12 @@
 	"INSERT INTO tab_rowfilter_child(a, b) VALUES(0,'0'),(30,'30'),(40,'40')"
 );
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (1, 2), (2, 4), (3, 6)"
+);
+
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync, tap_pub_virtual"
 );
 
 # wait for initial table synchronization to finish
@@ -550,6 +565,16 @@
 	"SELECT a FROM tab_rowfilter_child_sync ORDER BY 1");
 is($result, qq(), 'check initial data copy from tab_rowfilter_child_sync');
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (1, 2)      NO, 2 * 2 <= 10
+# - INSERT (2, 4)      NO, 4 * 2 <= 10
+# - INSERT (3, 6)      YES, 6 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is($result, qq(3|6),
+	'check initial data copy from table tab_rowfilter_virtual');
+
 # The following commands are executed after CREATE SUBSCRIPTION, so these SQL
 # commands are for testing normal logical replication behavior.
 #
@@ -582,6 +607,8 @@
 	"INSERT INTO tab_rowfilter_child (a, b) VALUES (13, '13'), (17, '17')");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rowfilter_viaroot_part (a) VALUES (14), (15), (16)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (4, 3), (5, 7)");
 
 $node_publisher->wait_for_catchup($appname);
 
@@ -725,6 +752,15 @@
 	'check replicated rows to tab_rowfilter_inherited and tab_rowfilter_child'
 );
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (4, 3)      NO, 3 * 2 <= 10
+# - INSERT (5, 7)      YES, 7 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is( $result, qq(3|6
+5|7), 'check replicated rows to tab_rowfilter_virtual');
+
 # UPDATE the non-toasted column for table tab_rowfilter_toast
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_rowfilter_toast SET b = '1'");

base-commit: ce9a74707d4cf7768cff06298d09c7f7e823341d
-- 
2.47.1

From 146018b9b78de2b858a97748217c4554eee28b3c Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 14 Jan 2025 14:20:52 +0100
Subject: [PATCH v12 2/2] Logical replication vs. virtual generated columns

Commits 745217a051a and 7054186c4eb (with subsequent amendments in
5b0c46ea093, 8fcd80258bc, 87ce27de696) added support for using
(stored) generated columns in logical replication.  But this doesn't
work for virtual generated columns, because their value is not
available in logical decoding.  This patch re-enables the original
prohibitions, but this time for virtual generated columns only.

The publication option "publish_generated_columns" and some related
internal variables are not renamed, but maybe they should be.

Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 doc/src/sgml/ddl.sgml                       |  4 +++-
 doc/src/sgml/logical-replication.sgml       |  2 +-
 doc/src/sgml/ref/create_publication.sgml    |  6 +++---
 src/backend/catalog/pg_publication.c        | 21 +++++++++++++++++----
 src/backend/replication/logical/proto.c     |  5 +++++
 src/backend/replication/logical/relation.c  |  4 ++--
 src/backend/replication/logical/tablesync.c |  4 ++--
 src/backend/replication/pgoutput/pgoutput.c |  2 +-
 src/test/regress/expected/publication.out   |  9 +++++++--
 src/test/regress/sql/publication.sql        |  8 ++++++--
 src/test/subscription/t/031_column_list.pl  | 14 ++++++++------
 11 files changed, 55 insertions(+), 24 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 502dd154645..16dc0212669 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -539,11 +539,13 @@ <title>Generated Columns</title>
     </listitem>
     <listitem>
      <para>
-      Generated columns are allowed to be replicated during logical replication
+      Stored generated columns are allowed to be replicated during logical replication
       according to the <command>CREATE PUBLICATION</command> parameter
       <link linkend="sql-createpublication-params-with-publish-generated-columns">
       <literal>publish_generated_columns</literal></link> or by including them
       in the column list of the <command>CREATE PUBLICATION</command> command.
+      Virtual generated columns are skipped for logical replication and cannot be
+      specified in a <command>CREATE PUBLICATION</command> column list.
      </para>
     </listitem>
    </itemizedlist>
diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index 8290cd1a083..83678da40a8 100644
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -1438,7 +1438,7 @@ <title>Column Lists</title>
    copied.  However, if the subscriber is from a release prior to 15, then
    all the columns in the table are copied during initial data synchronization,
    ignoring any column lists. If the subscriber is from a release prior to 18,
-   then initial table synchronization won't copy generated columns even if they
+   then initial table synchronization won't copy stored generated columns even if they
    are defined in the publisher.
   </para>
 
diff --git a/doc/src/sgml/ref/create_publication.sgml b/doc/src/sgml/ref/create_publication.sgml
index 5e25536554a..f61cea59725 100644
--- a/doc/src/sgml/ref/create_publication.sgml
+++ b/doc/src/sgml/ref/create_publication.sgml
@@ -89,7 +89,7 @@ <title>Parameters</title>
 
      <para>
       When a column list is specified, only the named columns are replicated.
-      The column list can contain generated columns as well. If no column list
+      The column list can contain stored generated columns as well. If no column list
       is specified, all table columns (except generated columns) are replicated
       through this publication, including any columns added later. It has no
       effect on <literal>TRUNCATE</literal> commands. See
@@ -193,7 +193,7 @@ <title>Parameters</title>
         <term><literal>publish_generated_columns</literal> (<type>boolean</type>)</term>
         <listitem>
          <para>
-          Specifies whether the generated columns present in the tables
+          Specifies whether the stored generated columns present in the tables
           associated with the publication should be replicated.
           The default is <literal>false</literal>.
          </para>
@@ -201,7 +201,7 @@ <title>Parameters</title>
          <note>
           <para>
            If the subscriber is from a release prior to 18, then initial table
-           synchronization won't copy generated columns even if parameter
+           synchronization won't copy stored generated columns even if parameter
            <literal>publish_generated_columns</literal> is true in the
            publisher.
           </para>
diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c
index b89098f5e99..c56937d7204 100644
--- a/src/backend/catalog/pg_publication.c
+++ b/src/backend/catalog/pg_publication.c
@@ -546,7 +546,8 @@ publication_add_relation(Oid pubid, PublicationRelInfo *pri,
  * pub_collist_validate
  *		Process and validate the 'columns' list and ensure the columns are all
  *		valid to use for a publication.  Checks for and raises an ERROR for
- * 		any unknown columns, system columns, or duplicate columns.
+ *		any unknown columns, system columns, duplicate columns, or virtual
+ *		generated columns.
  *
  * Looks up each column's attnum and returns a 0-based Bitmapset of the
  * corresponding attnums.
@@ -556,6 +557,7 @@ pub_collist_validate(Relation targetrel, List *columns)
 {
 	Bitmapset  *set = NULL;
 	ListCell   *lc;
+	TupleDesc   tupdesc = RelationGetDescr(targetrel);
 
 	foreach(lc, columns)
 	{
@@ -574,6 +576,12 @@ pub_collist_validate(Relation targetrel, List *columns)
 					errmsg("cannot use system column \"%s\" in publication column list",
 						   colname));
 
+		if (TupleDescAttr(tupdesc, attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+					errmsg("cannot use virtual generated column \"%s\" in publication column list",
+						   colname));
+
 		if (bms_is_member(attnum, set))
 			ereport(ERROR,
 					errcode(ERRCODE_DUPLICATE_OBJECT),
@@ -622,7 +630,8 @@ pub_collist_to_bitmapset(Bitmapset *columns, Datum pubcols, MemoryContext mcxt)
 /*
  * Returns a bitmap representing the columns of the specified table.
  *
- * Generated columns are included if include_gencols is true.
+ * Stored generated columns are included if include_gencols is true.  Virtual
+ * generated columns are never included.
  */
 Bitmapset *
 pub_form_cols_map(Relation relation, bool include_gencols)
@@ -634,7 +643,9 @@ pub_form_cols_map(Relation relation, bool include_gencols)
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		if (att->attisdropped || (att->attgenerated && !include_gencols))
+		if (att->attisdropped ||
+			att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ||
+			(att->attgenerated && !include_gencols))
 			continue;
 
 		result = bms_add_member(result, att->attnum);
@@ -1276,7 +1287,9 @@ pg_get_publication_tables(PG_FUNCTION_ARGS)
 			{
 				Form_pg_attribute att = TupleDescAttr(desc, i);
 
-				if (att->attisdropped || (att->attgenerated && !pub->pubgencols))
+				if (att->attisdropped ||
+					att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ||
+					(att->attgenerated && !pub->pubgencols))
 					continue;
 
 				attnums[nattnums++] = att->attnum;
diff --git a/src/backend/replication/logical/proto.c b/src/backend/replication/logical/proto.c
index bef350714db..6b412019731 100644
--- a/src/backend/replication/logical/proto.c
+++ b/src/backend/replication/logical/proto.c
@@ -1260,6 +1260,8 @@ logicalrep_message_type(LogicalRepMsgType action)
  *
  * Note that generated columns can be published only when present in a
  * publication column list, or when include_gencols is true.
+ *
+ * Virtual generated columns are never published.
  */
 bool
 logicalrep_should_publish_column(Form_pg_attribute att, Bitmapset *columns,
@@ -1268,6 +1270,9 @@ logicalrep_should_publish_column(Form_pg_attribute att, Bitmapset *columns,
 	if (att->attisdropped)
 		return false;
 
+	if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return false;
+
 	/* If a column list is provided, publish only the cols in that list. */
 	if (columns)
 		return bms_is_member(att->attnum, columns);
diff --git a/src/backend/replication/logical/relation.c b/src/backend/replication/logical/relation.c
index 67aab02ff76..1fea66a2604 100644
--- a/src/backend/replication/logical/relation.c
+++ b/src/backend/replication/logical/relation.c
@@ -455,8 +455,8 @@ logicalrep_rel_open(LogicalRepRelId remoteid, LOCKMODE lockmode)
 			entry->attrmap->attnums[i] = attnum;
 			if (attnum >= 0)
 			{
-				/* Remember which subscriber columns are generated. */
-				if (attr->attgenerated)
+				/* Remember which subscriber columns are stored generated. */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_STORED)
 					generatedattrs = bms_add_member(generatedattrs, attnum);
 
 				missingatts = bms_del_member(missingatts, attnum);
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 6af5c9fe16c..68ab03a8e6b 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -947,9 +947,9 @@ fetch_remote_table_info(char *nspname, char *relname, LogicalRepRelation *lrel,
 					 "       a.atttypid,"
 					 "       a.attnum = ANY(i.indkey)");
 
-	/* Generated columns can be replicated since version 18. */
+	/* Stored generated columns can be replicated since version 18. */
 	if (server_version >= 180000)
-		appendStringInfo(&cmd, ", a.attgenerated != ''");
+		appendStringInfo(&cmd, ", a.attgenerated = '%c'", ATTRIBUTE_GENERATED_STORED);
 
 	appendStringInfo(&cmd,
 					 "  FROM pg_catalog.pg_attribute a"
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 2ee48e1b4c0..4a9ce8243aa 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -1035,7 +1035,7 @@ check_and_init_gencol(PGOutputData *data, List *publications,
 	{
 		Form_pg_attribute att = TupleDescAttr(desc, i);
 
-		if (att->attgenerated)
+		if (att->attgenerated == ATTRIBUTE_GENERATED_STORED)
 		{
 			gencolpresent = true;
 			break;
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index 7cc405e002d..c11ffa5a889 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -727,7 +727,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 ERROR:  column "x" of relation "testpub_tbl5" does not exist
@@ -764,9 +766,12 @@ UPDATE testpub_tbl5 SET a = 1;
 ERROR:  cannot update table "testpub_tbl5"
 DETAIL:  Column list used by the publication does not cover the replica identity.
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
+ERROR:  cannot use virtual generated column "e" in publication column list
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
 ALTER TABLE testpub_tbl5 REPLICA IDENTITY USING INDEX testpub_tbl5_b_key;
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index 3b03fb647f1..d05f21a8472 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -447,7 +447,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 -- error: replica identity "a" not included in the column list
@@ -474,9 +476,11 @@ CREATE UNIQUE INDEX testpub_tbl5_b_key ON testpub_tbl5 (b, c);
 UPDATE testpub_tbl5 SET a = 1;
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
 
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
 
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
diff --git a/src/test/subscription/t/031_column_list.pl b/src/test/subscription/t/031_column_list.pl
index 7a535e76b08..b16dea9aa17 100644
--- a/src/test/subscription/t/031_column_list.pl
+++ b/src/test/subscription/t/031_column_list.pl
@@ -1202,14 +1202,16 @@
 is( $result, qq(t
 t), 'check the number of columns in the old tuple');
 
-# TEST: Dropped columns are not considered for the column list, and generated
-# columns are not replicated if they are not explicitly included in the column
-# list. So, the publication having a column list except for those columns and a
-# publication without any column list (aka all columns as part of the columns
-# list) are considered to have the same column list.
+# TEST: Dropped columns and virtual generated columns are not
+# considered for the column list, and stored generated columns are not
+# replicated if they are not explicitly included in the column
+# list. So, the publication having a column list except for those
+# columns and a publication without any column list (aka all columns
+# as part of the columns list) are considered to have the same column
+# list.
 $node_publisher->safe_psql(
 	'postgres', qq(
-	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED);
+	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED, e int GENERATED ALWAYS AS (a + 2) VIRTUAL);
 	ALTER TABLE test_mix_4 DROP COLUMN c;
 
 	CREATE PUBLICATION pub_mix_7 FOR TABLE test_mix_4 (a, b);
-- 
2.47.1

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
new file mode 100644
index b6464d4..2c9d8ae
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,7 +96,8 @@ static List *matchLocks(CmdType event, R
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
-static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+								  RangeTblEntry *rte, int result_relation);
 
 
 /*
@@ -2326,8 +2327,10 @@ fireRIRrules(Query *parsetree, List *act
 		 * Note that subqueries in virtual generated column expressions are
 		 * not currently supported, so this cannot add any more sublinks.
 		 */
-		parsetree = (Query *) expand_generated_columns_internal((Node *) parsetree,
-																rel, rt_index, rte);
+		parsetree = (Query *)
+			expand_generated_columns_internal((Node *) parsetree,
+											  rel, rt_index, rte,
+											  parsetree->resultRelation);
 
 		table_close(rel, NoLock);
 	}
@@ -4449,9 +4452,18 @@ RewriteQuery(Query *parsetree, List *rew
  * If the table contains virtual generated columns, build a target list
  * containing the expanded expressions and use ReplaceVarsFromTargetList() to
  * do the replacements.
+ *
+ * Vars matching rt_index at the current query level are replaced by the
+ * virtual generated column expressions from rel, if there are any.
+ *
+ * The caller must also provide rte, the RTE describing the target relation,
+ * in order to handle any whole-row Vars referencing the target, and
+ * result_relation, the index of the result relation, if this is part of an
+ * INSERT/UPDATE/DELETE/MERGE query.
  */
 static Node *
-expand_generated_columns_internal(Node *node, Relation rel, int rt_index, RangeTblEntry *rte)
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+								  RangeTblEntry *rte, int result_relation)
 {
 	TupleDesc	tupdesc;
 
@@ -4502,7 +4514,10 @@ expand_generated_columns_internal(Node *
 
 		Assert(list_length(tlist) > 0);
 
-		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, REPLACEVARS_CHANGE_VARNO, rt_index, NULL);
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist,
+										 result_relation,
+										 REPLACEVARS_CHANGE_VARNO, rt_index,
+										 NULL);
 	}
 
 	return node;
@@ -4529,7 +4544,7 @@ expand_generated_columns_in_expr(Node *n
 		rte->rtekind = RTE_RELATION;
 		rte->relid = RelationGetRelid(rel);
 
-		node = expand_generated_columns_internal(node, rel, rt_index, rte);
+		node = expand_generated_columns_internal(node, rel, rt_index, rte, 0);
 	}
 
 	return node;
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
new file mode 100644
index 5a74c0a..367605d
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -190,7 +190,12 @@ SELECT * FROM gtest1 ORDER BY a;
  2 | 4
 (2 rows)
 
-UPDATE gtest1 SET a = 3 WHERE b = 4;
+UPDATE gtest1 SET a = 3 WHERE b = 4 RETURNING old.*, new.*;
+ a | b | a | b 
+---+---+---+---
+ 2 | 4 | 3 | 6
+(1 row)
+
 SELECT * FROM gtest1 ORDER BY a;
  a | b 
 ---+---
@@ -216,7 +221,14 @@ CREATE TABLE gtestm (
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
   WHEN MATCHED THEN UPDATE SET f1 = v.f1
-  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200);
+  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200)
+  RETURNING merge_action(), old.*, new.*;
+ merge_action | id | f1 | f2  | f3 | f4  | id | f1 | f2  | f3 | f4  
+--------------+----+----+-----+----+-----+----+----+-----+----+-----
+ UPDATE       |  1 |  5 | 100 | 10 | 200 |  1 | 10 | 100 | 20 | 200
+ INSERT       |    |    |     |    |     |  2 | 20 | 200 | 40 | 400
+(2 rows)
+
 SELECT * FROM gtestm ORDER BY id;
  id | f1 | f2  | f3 | f4  
 ----+----+-----+----+-----
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
new file mode 100644
index f855898..91aec4e
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -84,7 +84,7 @@ DROP TABLE gtestx;
 
 -- test UPDATE/DELETE quals
 SELECT * FROM gtest1 ORDER BY a;
-UPDATE gtest1 SET a = 3 WHERE b = 4;
+UPDATE gtest1 SET a = 3 WHERE b = 4 RETURNING old.*, new.*;
 SELECT * FROM gtest1 ORDER BY a;
 DELETE FROM gtest1 WHERE b = 2;
 SELECT * FROM gtest1 ORDER BY a;
@@ -100,7 +100,8 @@ CREATE TABLE gtestm (
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
   WHEN MATCHED THEN UPDATE SET f1 = v.f1
-  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200);
+  WHEN NOT MATCHED THEN INSERT VALUES (v.id, v.f1, 200)
+  RETURNING merge_action(), old.*, new.*;
 SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 

From 4574d76e2ba167d6bd36901e9362c2b3b997bc1d Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 27 Jan 2025 07:42:55 +0100
Subject: [PATCH v13] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

The syntax for the column definition is

    ... GENERATED ALWAYS AS (...) VIRTUAL

and VIRTUAL is also optional.  VIRTUAL is the default rather than
STORED to match various other SQL products.  (The SQL standard makes
no specification about this, but it also doesn't know about VIRTUAL or
STORED.)  (Also, virtual views are the default, rather than
materialized views.)

Virtual generated columns are stored in tuples as null values.  (A
very early version of this patch had the ambition to not store them at
all.  But so much stuff breaks or gets confused if you have tuples
where a column in the middle is completely missing.  This is a
compromise, and it still saves space over being forced to use stored
generated columns.  If we ever find a way to improve this, a bit of
pg_upgrade cleverness could allow for upgrades to a newer scheme.)

The capabilities and restrictions of virtual generated columns are
mostly the same as for stored generated columns.  In some cases, this
patch keeps virtual generated columns more restricted than they might
technically need to be, to keep the two kinds consistent.  Some of
that could maybe be relaxed later after separate careful
considerations.

Some functionality that is currently not supported, but could possibly
be added as incremental features, some easier than others:

- index on or using a virtual column
- hence also no unique constraints on virtual columns
- extended statistics on virtual columns
- foreign key constraints on virtual columns
- not-null constraints on virtual columns (check constraints are supported)
- ALTER TABLE / DROP EXPRESSION
- virtual column cannot have domain type
- virtual columns are not supported in logical replication

The tests in generated_virtual.sql have been copied over from
generated_stored.sql with the keyword replaced.  This way we can make
sure the behavior is mostly aligned, and the differences can be
visible.  Some tests for currently not supported features are
currently commented out.

Reviewed-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   6 +-
 doc/src/sgml/ddl.sgml                         |  46 +-
 doc/src/sgml/ref/alter_table.sgml             |  15 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  23 +-
 src/backend/catalog/pg_publication.c          |  10 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  33 +-
 src/backend/commands/publicationcmds.c        |   3 +
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 196 ++++-
 src/backend/commands/trigger.c                |  45 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/executor/execUtils.c              |   4 +-
 src/backend/executor/nodeModifyTable.c        |  41 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  16 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 133 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/catversion.h              |   2 +-
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/executor/nodeModifyTable.h        |   6 +-
 src/include/nodes/execnodes.h                 |   3 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     |  21 +-
 ...rated_stored.out => generated_virtual.out} | 754 ++++++++----------
 src/test/regress/expected/publication.out     |  27 +-
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/expected/stats_ext.out       |  23 +
 src/test/regress/parallel_schedule            |   2 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  12 +-
 ...rated_stored.sql => generated_virtual.sql} | 300 +++----
 src/test/regress/sql/publication.sql          |  22 +-
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/regress/sql/stats_ext.sql            |  14 +
 src/test/subscription/t/011_generated.pl      |  39 +-
 src/test/subscription/t/028_row_filter.pl     |  38 +-
 src/test/subscription/t/031_column_list.pl    |   2 +-
 71 files changed, 1530 insertions(+), 766 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (72%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (74%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 85252cbdbcf..6341f64601b 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7395,65 +7395,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7461,28 +7464,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index b58ab6ee586..1598d9e0862 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1859,12 +1859,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 8ad0ed10b3a..0b5d883fbbb 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1307,8 +1307,10 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.  A stored generated column is physically stored like a normal
+       column.  A virtual generated column is physically stored as a null
+       value, with the actual value being computed at run time.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index dea04d64db6..482785370f5 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
@@ -502,6 +507,26 @@ <title>Generated Columns</title>
       particular role can read from a generated column but not from the
       underlying base columns.
      </para>
+
+     <para>
+      For virtual generated columns, this is only fully secure if the
+      generation expression uses only leakproof functions (see <xref
+      linkend="sql-createfunction"/>), but this is not enforced by the system.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Privileges of functions used in generation expressions are checked when
+      the expression is actually executed, on write or read respectively, as
+      if the generation expression had been called directly from the query
+      using the generated column.  The user of a generated column must have
+      permissions to call all functions used by the generation expression.
+      Functions in the generation expression are executed with the privileges
+      of the user executing the query or the function owner, depending on
+      whether the functions are defined as <literal>SECURITY INVOKER</literal>
+      or <literal>SECURITY DEFINER</literal>.
+      <!-- matches create_view.sgml -->
+     </para>
     </listitem>
     <listitem>
      <para>
@@ -519,6 +544,7 @@ <title>Generated Columns</title>
       <link linkend="sql-createpublication-params-with-publish-generated-columns">
       <literal>publish_generated_columns</literal></link> or by including them
       in the column list of the <command>CREATE PUBLICATION</command> command.
+      This is currently only supported for stored generated columns.
      </para>
     </listitem>
    </itemizedlist>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index f9576da435e..8e56b8e59b0 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -264,8 +264,8 @@ <title>Description</title>
     <listitem>
      <para>
       This form replaces the expression of a generated column.  Existing data
-      in the column is rewritten and all the future changes will apply the new
-      generation expression.
+      in a stored generated column is rewritten and all the future changes
+      will apply the new generation expression.
      </para>
     </listitem>
    </varlistentry>
@@ -279,10 +279,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index 0dcd9ca6f87..e0b0e075c2c 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 [ ENFORCED | NOT ENFORCED ]
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
@@ -283,7 +283,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -292,10 +292,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 2237321cb4f..060793404f1 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2489,9 +2493,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index c3c0faf7a1b..e9214dcf1b1 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -293,6 +293,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index fe197447912..ed2195f14b2 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -342,6 +342,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -640,6 +641,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a4003cf59e1..c0bec014154 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 57ef466acce..956f196fc95 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -507,7 +507,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -582,6 +582,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
@@ -2553,6 +2564,11 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
+			/* TODO: see transformColumnDefinition() */
+			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("not-null constraints are not supported on virtual generated columns"));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2868,6 +2884,11 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					errmsg("cannot add not-null constraint on system column \"%s\"",
 						   strVal(linitial(constr->keys))));
+		/* TODO: see transformColumnDefinition() */
+		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("not-null constraints are not supported on virtual generated columns"));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c
index 7900a8f6a13..60e77753b94 100644
--- a/src/backend/catalog/pg_publication.c
+++ b/src/backend/catalog/pg_publication.c
@@ -546,7 +546,8 @@ publication_add_relation(Oid pubid, PublicationRelInfo *pri,
  * pub_collist_validate
  *		Process and validate the 'columns' list and ensure the columns are all
  *		valid to use for a publication.  Checks for and raises an ERROR for
- * 		any unknown columns, system columns, or duplicate columns.
+ *		any unknown columns, system columns, duplicate columns, or virtual
+ *		generated columns.
  *
  * Looks up each column's attnum and returns a 0-based Bitmapset of the
  * corresponding attnums.
@@ -556,6 +557,7 @@ pub_collist_validate(Relation targetrel, List *columns)
 {
 	Bitmapset  *set = NULL;
 	ListCell   *lc;
+	TupleDesc	tupdesc = RelationGetDescr(targetrel);
 
 	foreach(lc, columns)
 	{
@@ -574,6 +576,12 @@ pub_collist_validate(Relation targetrel, List *columns)
 					errmsg("cannot use system column \"%s\" in publication column list",
 						   colname));
 
+		if (TupleDescAttr(tupdesc, attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+					errmsg("cannot use virtual generated column \"%s\" in publication column list",
+						   colname));
+
 		if (bms_is_member(attnum, set))
 			ereport(ERROR,
 					errcode(ERRCODE_DUPLICATE_OBJECT),
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 2a7769b1fd1..31926d7d056 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1037,6 +1037,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 59c836fc24d..b9220c54388 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1111,6 +1111,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1120,14 +1123,24 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 stmt->isconstraint ?
+					 errmsg("unique constraints on virtual generated columns are not supported") :
+					 errmsg("indexes on virtual generated columns are not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1140,6 +1153,24 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 stmt->isconstraint ?
+						 errmsg("unique constraints on virtual generated columns are not supported") :
+						 errmsg("indexes on virtual generated columns are not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index b49d9ab78bf..0f57e654a79 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -38,6 +38,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parse_collate.h"
 #include "parser/parse_relation.h"
+#include "rewrite/rewriteHandler.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -689,6 +690,8 @@ TransformPubWhereClauses(List *tables, const char *queryString,
 		/* Fix up collation information */
 		assign_expr_collations(pstate, whereclause);
 
+		whereclause = expand_generated_columns_in_expr(whereclause, pri->relation, 1);
+
 		/*
 		 * We allow only simple expressions in row filters. See
 		 * check_simple_rowfilter_expr_walker.
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index a817821bf6d..e24d540cd45 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index d617c4bc63d..047ba3a66d4 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3039,6 +3039,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3324,6 +3333,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6130,7 +6148,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7308,7 +7326,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7785,6 +7803,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8411,6 +8437,8 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	HeapTuple	tuple;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
+	char		attgenerated;
+	bool		rewrite;
 	Oid			attrdefoid;
 	ObjectAddress address;
 	Expr	   *defval;
@@ -8425,36 +8453,70 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 						colName, RelationGetRelationName(rel))));
 
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
-	attnum = attTup->attnum;
 
+	attnum = attTup->attnum;
 	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	attgenerated = attTup->attgenerated;
+	if (!attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 						colName, RelationGetRelationName(rel))));
-	ReleaseSysCache(tuple);
 
 	/*
-	 * Clear all the missing values if we're rewriting the table, since this
-	 * renders them pointless.
+	 * TODO: This could be done, just need to recheck any constraints
+	 * afterwards.
 	 */
-	RelationClearMissing(rel);
-
-	/* make sure we don't conflict with later attribute modifications */
-	CommandCounterIncrement();
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Find everything that depends on the column (constraints, indexes, etc),
-	 * and record enough information to let us recreate the objects after
-	 * rewrite.
+	 * We need to prevent this because a change of expression could affect a
+	 * row filter and inject expressions that are not permitted in a row
+	 * filter.  XXX We could try to have a more precise check to catch only
+	 * publications with row filters, or even re-verify the row filter
+	 * expressions.
 	 */
-	RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		GetRelationPublications(RelationGetRelid(rel)) != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
+
+	ReleaseSysCache(tuple);
+
+	if (rewrite)
+	{
+		/*
+		 * Clear all the missing values if we're rewriting the table, since
+		 * this renders them pointless.
+		 */
+		RelationClearMissing(rel);
+
+		/* make sure we don't conflict with later attribute modifications */
+		CommandCounterIncrement();
+
+		/*
+		 * Find everything that depends on the column (constraints, indexes,
+		 * etc), and record enough information to let us recreate the objects
+		 * after rewrite.
+		 */
+		RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	}
 
 	/*
 	 * Drop the dependency records of the GENERATED expression, in particular
@@ -8483,7 +8545,7 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	rawEnt->attnum = attnum;
 	rawEnt->raw_default = newExpr;
 	rawEnt->missingMode = false;
-	rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
+	rawEnt->generated = attgenerated;
 
 	/* Store the generated expression */
 	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
@@ -8492,16 +8554,19 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	/* Make above new expression visible */
 	CommandCounterIncrement();
 
-	/* Prepare for table rewrite */
-	defval = (Expr *) build_column_default(rel, attnum);
+	if (rewrite)
+	{
+		/* Prepare for table rewrite */
+		defval = (Expr *) build_column_default(rel, attnum);
 
-	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
-	newval->attnum = attnum;
-	newval->expr = expression_planner(defval);
-	newval->is_generated = true;
+		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+		newval->attnum = attnum;
+		newval->expr = expression_planner(defval);
+		newval->is_generated = true;
 
-	tab->newvals = lappend(tab->newvals, newval);
-	tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+		tab->newvals = lappend(tab->newvals, newval);
+		tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+	}
 
 	/* Drop any pg_statistic entry for the column */
 	RemoveStatistics(RelationGetRelid(rel), attnum);
@@ -8590,17 +8655,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8743,6 +8821,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9925,6 +10013,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12305,7 +12406,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	val = SysCacheGetAttrNotNull(CONSTROID, contuple,
 								 Anum_pg_constraint_conbin);
 	conbin = TextDatumGetCString(val);
-	newcon->qual = (Node *) stringToNode(conbin);
+	newcon->qual = expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 	/* Find or create work queue entry for this table */
 	tab = ATGetQueueEntry(wqueue, rel);
@@ -13483,8 +13584,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13557,11 +13662,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16550,6 +16656,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18797,8 +18911,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18880,9 +18997,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 7a5ffe32f60..97c087929f3 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static HeapTuple check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -2504,6 +2507,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3061,6 +3066,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3491,6 +3498,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6621,3 +6630,37 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and replace the
+ * value with null if so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static HeapTuple
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return tuple;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			if (!heap_attisnull(tuple, i + 1, tupdesc))
+			{
+				int			replCol = i + 1;
+				Datum		replValue = 0;
+				bool		replIsnull = true;
+
+				tuple = heap_modify_tuple_by_cols(tuple, tupdesc, 1, &replCol, &replValue, &replIsnull);
+			}
+		}
+	}
+
+	return tuple;
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 1127e6f11eb..c62a4a38cd8 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2335,6 +2335,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index fb8dba3ab2c..bab5dfe47a0 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1762,6 +1762,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 				continue;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2309,7 +2310,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 7c539de5cf2..7097ad15a9a 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1382,8 +1382,8 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (relinfo->ri_GeneratedExprsU == NULL)
-		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+	if (!relinfo->ri_Generated_valid)
+		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index bc82e035ba2..2d490cf7ca5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -391,11 +391,14 @@ ExecCheckTIDVisible(EState *estate,
 }
 
 /*
- * Initialize to compute stored generated columns for a tuple
+ * Initialize generated columns handling for a tuple
+ *
+ * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI or
+ * ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
+ * This is used only for stored generated columns.
  *
- * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI
- * or ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
  * If cmdType == CMD_UPDATE, the ri_extraUpdatedCols field is filled too.
+ * This is used by both stored and virtual generated columns.
  *
  * Note: usually, a given query would need only one of ri_GeneratedExprsI and
  * ri_GeneratedExprsU per result rel; but MERGE can need both, and so can
@@ -403,9 +406,9 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-						EState *estate,
-						CmdType cmdtype)
+ExecInitGenerated(ResultRelInfo *resultRelInfo,
+				  EState *estate,
+				  CmdType cmdtype)
 {
 	Relation	rel = resultRelInfo->ri_RelationDesc;
 	TupleDesc	tupdesc = RelationGetDescr(rel);
@@ -416,7 +419,7 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
+	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
 		return;
 
 	/*
@@ -442,7 +445,9 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated)
 		{
 			Expr	   *expr;
 
@@ -467,8 +472,11 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-			ri_NumGeneratedNeeded++;
+			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
+			{
+				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+				ri_NumGeneratedNeeded++;
+			}
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -478,6 +486,13 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		}
 	}
 
+	if (ri_NumGeneratedNeeded == 0)
+	{
+		/* didn't need it after all */
+		pfree(ri_GeneratedExprs);
+		ri_GeneratedExprs = NULL;
+	}
+
 	/* Save in appropriate set of fields */
 	if (cmdtype == CMD_UPDATE)
 	{
@@ -496,6 +511,8 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
+	resultRelInfo->ri_Generated_valid = true;
+
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -526,7 +543,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -534,7 +551,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index d7f9c00c409..d3887628d46 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -636,7 +636,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -784,7 +784,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3995,7 +3995,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -4003,6 +4003,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4050,6 +4051,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17990,6 +17997,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18645,6 +18653,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 101fba34b18..04ecf64b1fc 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -712,7 +712,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ca028d2a66d..eb7716cd84c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -988,6 +988,20 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns"),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index a363c88ffc0..a392b93a179 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1009,7 +1010,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index b74f2acc327..8c998176488 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+											   RangeTblEntry *rte, int result_relation);
 
 
 /*
@@ -986,7 +988,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2209,6 +2212,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2222,10 +2229,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2314,6 +2322,16 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *)
+			expand_generated_columns_internal((Node *) parsetree,
+											  rel, rt_index, rte,
+											  parsetree->resultRelation);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4428,6 +4446,111 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ *
+ * Vars matching rt_index at the current query level are replaced by the
+ * virtual generated column expressions from rel, if there are any.
+ *
+ * The caller must also provide rte, the RTE describing the target relation,
+ * in order to handle any whole-row Vars referencing the target, and
+ * result_relation, the index of the result relation, if this is part of an
+ * INSERT/UPDATE/DELETE/MERGE query.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+								  RangeTblEntry *rte, int result_relation)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist,
+										 result_relation,
+										 REPLACEVARS_CHANGE_VARNO, rt_index,
+										 NULL);
+	}
+
+	return node;
+}
+
+/*
+ * Expand virtual generated columns in an expression
+ *
+ * This is for expressions that are not part of a query, such as default
+ * expressions or index predicates.  The rt_index is usually 1.
+ */
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		/* eref needs to be set, but the actual name doesn't matter */
+		rte->eref = makeAlias(RelationGetRelationName(rel), NIL);
+		rte->rtekind = RTE_RELATION;
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte, 0);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ee39d085ebe..9e9f5c621c8 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,6 +592,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -674,6 +676,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index af857f00c7c..1a662f387c8 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16190,6 +16190,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 805ba9f49fd..bc5d9222a20 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3706,12 +3706,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 2e84b61f184..b342d91546f 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2123,6 +2123,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index ff27df9e9a6..396eeb7a0bb 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -44,6 +44,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index e3a308024de..8b9a8453f77 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202501232
+#define CATALOG_VERSION_NO	202501271
 
 #endif
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index cad830dc39c..19c594458bd 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b33c315d233..deaa515fe53 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -225,6 +225,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index d1ddc39ad37..bf3b592e28f 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,9 +15,9 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-									EState *estate,
-									CmdType cmdtype);
+extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+							  EState *estate,
+							  CmdType cmdtype);
 
 extern void ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 									   EState *estate, TupleTableSlot *slot,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index d0f2dca5928..f4ddba00975 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -556,6 +556,9 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
+	/* true if the above have been computed */
+	bool		ri_Generated_valid;
+
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index ffe155ee20e..8dd421fa0ef 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2812,6 +2812,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index cf2917ad07e..40cf090ce61 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -491,6 +491,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index d258b26375f..88fe13c5f4f 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index feb6a76b56c..08c8492050e 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 910de9120f2..96a134d1561 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2555,6 +2555,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index e0613891351..2cebe382432 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 7653326420e..3ce0dd1831c 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,3 +1,4 @@
+-- keep these tests aligned with generated_virtual.sql
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -357,6 +358,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -868,6 +873,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -881,6 +891,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1188,9 +1203,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1471,7 +1486,7 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
  x      | integer |           |          | generated always as (b * 2) stored
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 72%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 7653326420e..35638812be9 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,9 +1,10 @@
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+-- keep these tests aligned with generated_stored.sql
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -12,89 +13,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -165,16 +166,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -220,8 +215,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -244,7 +239,7 @@ SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 CREATE TABLE gtestm (
   a int PRIMARY KEY,
-  b int GENERATED ALWAYS AS (a * 2) STORED
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
 MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
@@ -318,11 +313,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -341,12 +336,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -357,26 +352,30 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
 INSERT INTO gtestx (a, x) VALUES (11, 22);
 SELECT * FROM gtest1;
- a  |  b  
-----+-----
-  3 |   6
-  4 |   8
- 11 | 242
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
 (3 rows)
 
 SELECT * FROM gtestx;
@@ -388,9 +387,9 @@ SELECT * FROM gtestx;
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -403,28 +402,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -441,8 +440,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -463,7 +462,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -528,7 +527,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -537,7 +536,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -552,7 +551,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -567,11 +566,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -580,7 +579,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -588,24 +587,24 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 INSERT INTO gtest11 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest11 TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
+CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
 INSERT INTO gtest12 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c), INSERT ON gtest12 TO regress_user11;
 SET ROLE regress_user11;
@@ -620,15 +619,9 @@ SELECT a, c FROM gtest11;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12;  -- currently not allowed because of function permissions, should arguably be allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12;  -- allowed (does not actually invoke the function)
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
@@ -638,227 +631,147 @@ DROP TABLE gtest11, gtest12;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+DETAIL:  Failing row contains (30, virtual).
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
 -- check with whole-row reference
-CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
 INSERT INTO gtest20c VALUES (1);  -- ok
 INSERT INTO gtest20c VALUES (NULL);  -- fails
 ERROR:  new row for relation "gtest20c" violates check constraint "whole_row_check"
-DETAIL:  Failing row contains (null, null).
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+DETAIL:  Failing row contains (null, virtual).
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+LINE 1: ... b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+                                                             ^
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+DROP TABLE gtest21ax;
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  unique constraints on virtual generated columns are not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
-CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
-INSERT INTO gtest24r (a) VALUES (4);  -- ok
-INSERT INTO gtest24r (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -868,6 +781,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -882,32 +800,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -918,7 +841,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
@@ -928,7 +851,7 @@ SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
  gtest_child | 07-15-2016 |  2 |  4
 (2 rows)
 
-SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child2 | 08-15-2016 |  3 | 66
@@ -944,95 +867,95 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 4)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 10)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  8
+ gtest_child2 | 08-15-2016 |  3 | 12
+ gtest_child3 | 09-13-2016 |  1 |  4
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -1045,20 +968,20 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
  a | b  
 ---+----
@@ -1066,16 +989,16 @@ SELECT * FROM gtest25 ORDER BY a;
  4 | 12
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
 ERROR:  cannot use generated column "b" in column generation expression
 DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
  a | b  | c  |  x  |  d  |  y  
 ---+----+----+-----+-----+-----
@@ -1084,15 +1007,15 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
+ b      | integer          |           |          | generated always as (a * 3)
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1100,7 +1023,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1108,12 +1031,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1129,20 +1052,19 @@ LINE 1: ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0...
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1151,12 +1073,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1168,7 +1090,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1179,18 +1101,18 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1201,97 +1123,97 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 3)
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
  3 |  9
  4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 5 | 15
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
-
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
 -- composite type dependencies
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
 DROP TABLE gtest31_1, gtest31_2;
 -- Check it for a partitioned table, too
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
@@ -1299,7 +1221,7 @@ DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1352,7 +1274,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1362,12 +1284,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1377,8 +1299,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1428,7 +1350,7 @@ CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 INFO:  gtest12_01: BEFORE: new = (1,)
-INFO:  gtest12_03: BEFORE: new = (10,300)
+INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1436,9 +1358,9 @@ SELECT * FROM gtest26 ORDER BY a;
 (1 row)
 
 UPDATE gtest26 SET a = 11 WHERE a = 10;
-INFO:  gtest12_01: BEFORE: old = (10,20)
+INFO:  gtest12_01: BEFORE: old = (10,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (10,20)
+INFO:  gtest12_03: BEFORE: old = (10,)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1451,27 +1373,27 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index bc3898fbe58..99e98bcbdce 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -442,7 +442,7 @@ LINE 1: ...ICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
                                                              ^
 DETAIL:  User-defined operators are not allowed.
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 ERROR:  invalid publication WHERE expression
 LINE 1: ...ON testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf...
@@ -523,17 +523,33 @@ Tables:
 Tables from schemas:
     "testpub_rf_schema2"
 
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+ERROR:  invalid publication WHERE expression
+DETAIL:  User-defined or built-in mutable functions are not allowed.
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication
+DETAIL:  Column "y" of relation "testpub_rf_tbl7" is a virtual generated column.
+RESET client_min_messages;
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
@@ -711,7 +727,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 ERROR:  column "x" of relation "testpub_tbl5" does not exist
@@ -748,9 +766,12 @@ UPDATE testpub_tbl5 SET a = 1;
 ERROR:  cannot update table "testpub_tbl5"
 DETAIL:  Column list used by the publication does not cover the replica identity.
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
+ERROR:  cannot use virtual generated column "e" in publication column list
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
 ALTER TABLE testpub_tbl5 REPLICA IDENTITY USING INDEX testpub_tbl5_b_key;
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index fd5654df35e..87929191d06 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index a4c7be487ef..9a820404d3f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -66,6 +66,29 @@ ERROR:  syntax error at or near ","
 LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
                                    ^
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
+DROP TABLE ext_stats_test1;
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
 CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 1edd9e45ebb..e63ee2cf2bb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -78,7 +78,7 @@ test: brin_bloom brin_multi
 # psql depends on create_am
 # amutils depends on geometry, create_index_spgist, hash_index, brin
 # ----------
-test: create_table_like alter_generic alter_operator misc async dbsize merge misc_functions sysviews tsrf tid tidscan tidrangescan collate.utf8 collate.icu.utf8 incremental_sort create_role without_overlaps
+test: create_table_like alter_generic alter_operator misc async dbsize merge misc_functions sysviews tsrf tid tidscan tidrangescan collate.utf8 collate.icu.utf8 incremental_sort create_role without_overlaps generated_virtual
 
 # collate.linux.utf8 and collate.icu.utf8 tests cannot be run in parallel with each other
 test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8 collate.windows.win1252
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index f99f186f2d6..eea50e34c2d 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -955,6 +955,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index a41f8b83d77..63a60303659 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index 6fbfcbf9615..b7749ce355f 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,3 +1,6 @@
+-- keep these tests aligned with generated_virtual.sql
+
+
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -149,6 +152,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 INSERT INTO gtestx (a, x) VALUES (11, 22);
@@ -438,6 +442,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -447,6 +454,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -715,4 +725,4 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 74%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index 6fbfcbf9615..34870813910 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,51 +1,54 @@
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+-- keep these tests aligned with generated_stored.sql
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
+
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -68,7 +71,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -91,8 +94,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -104,7 +107,7 @@ CREATE TABLE gtestm (
 
 CREATE TABLE gtestm (
   a int PRIMARY KEY,
-  b int GENERATED ALWAYS AS (a * 2) STORED
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
 MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
@@ -141,15 +144,16 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 INSERT INTO gtestx (a, x) VALUES (11, 22);
 SELECT * FROM gtest1;
@@ -157,9 +161,9 @@ CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -171,28 +175,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -232,12 +236,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -247,7 +251,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -258,35 +262,35 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 INSERT INTO gtest11 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest11 TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
+CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
 INSERT INTO gtest12 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c), INSERT ON gtest12 TO regress_user11;
 
@@ -294,8 +298,8 @@ CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b
 SELECT a, b FROM gtest11;  -- not allowed
 SELECT a, c FROM gtest11;  -- allowed
 SELECT gf1(10);  -- not allowed
-INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
-SELECT a, c FROM gtest12;  -- allowed (does not actually invoke the function)
+INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12;  -- currently not allowed because of function permissions, should arguably be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
@@ -304,133 +308,139 @@ CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
 -- check with whole-row reference
-CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
 INSERT INTO gtest20c VALUES (1);  -- ok
 INSERT INTO gtest20c VALUES (NULL);  -- fails
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+DROP TABLE gtest21ax;
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
-CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
-INSERT INTO gtest24r (a) VALUES (4);  -- ok
-INSERT INTO gtest24r (a) VALUES (6);  -- error
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -438,6 +448,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -448,6 +461,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,7 +473,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
-SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
 SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -481,21 +497,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -503,7 +519,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -517,7 +533,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -529,7 +545,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -543,20 +559,20 @@ CREATE TABLE gtest29 (
 SELECT * FROM gtest29;
 \d gtest29
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
 SELECT * FROM gtest29;
 \d gtest29
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -565,7 +581,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -574,13 +590,13 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
 -- composite type dependencies
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 DROP TABLE gtest31_1, gtest31_2;
 
 -- Check it for a partitioned table, too
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 DROP TABLE gtest31_1, gtest31_2;
@@ -588,7 +604,7 @@ CREATE TABLE gtest31_2 (x int, y gtest31_1);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -704,7 +720,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -715,4 +731,4 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index 47f0329c244..22ffb86747e 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -214,7 +214,7 @@ CREATE FUNCTION testpub_rf_func1(integer, integer) RETURNS boolean AS $$ SELECT
 CREATE OPERATOR =#> (PROCEDURE = testpub_rf_func1, LEFTARG = integer, RIGHTARG = integer);
 CREATE PUBLICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 -- fail - non-immutable functions are not allowed. random() is volatile.
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a < random());
@@ -261,18 +261,30 @@ CREATE PUBLICATION testpub6 FOR TABLES IN SCHEMA testpub_rf_schema2;
 ALTER PUBLICATION testpub6 SET TABLES IN SCHEMA testpub_rf_schema2, TABLE testpub_rf_schema2.testpub_rf_tbl6 WHERE (i < 99);
 RESET client_min_messages;
 \dRp+ testpub6
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+RESET client_min_messages;
 
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
@@ -435,7 +447,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 -- error: replica identity "a" not included in the column list
@@ -462,9 +476,11 @@ CREATE UNIQUE INDEX testpub_tbl5_b_key ON testpub_tbl5 (b, c);
 UPDATE testpub_tbl5 SET a = 1;
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
 
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
 
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index cf09f62eaba..f61dbbf9581 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 5c786b16c6f..75b04e5a136 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -45,6 +45,20 @@ CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
 CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+DROP TABLE ext_stats_test1;
 
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 5970bb47360..c7a4c52e4f2 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,11 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +57,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +70,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +89,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");
diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl
index e3a6d69da7e..e2c83670053 100644
--- a/src/test/subscription/t/028_row_filter.pl
+++ b/src/test/subscription/t/028_row_filter.pl
@@ -240,6 +240,9 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync PARTITION OF tab_rowfilter_parent_sync FOR VALUES FROM (1) TO (20)"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup structure on subscriber
 $node_subscriber->safe_psql('postgres',
@@ -294,6 +297,9 @@
 	"CREATE TABLE tab_rowfilter_parent_sync (a int)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync (a int)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup logical replication
 $node_publisher->safe_psql('postgres',
@@ -359,6 +365,11 @@
 	"CREATE PUBLICATION tap_pub_child_sync FOR TABLE tab_rowfilter_child_sync WHERE (a < 15)"
 );
 
+# publication using virtual generated column in row filter expression
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_virtual FOR TABLE tab_rowfilter_virtual WHERE (y > 10)"
+);
+
 #
 # The following INSERTs are executed before the CREATE SUBSCRIPTION, so these
 # SQL commands are for testing the initial data copy using logical replication.
@@ -407,8 +418,12 @@
 	"INSERT INTO tab_rowfilter_child(a, b) VALUES(0,'0'),(30,'30'),(40,'40')"
 );
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (1, 2), (2, 4), (3, 6)"
+);
+
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync, tap_pub_virtual"
 );
 
 # wait for initial table synchronization to finish
@@ -550,6 +565,16 @@
 	"SELECT a FROM tab_rowfilter_child_sync ORDER BY 1");
 is($result, qq(), 'check initial data copy from tab_rowfilter_child_sync');
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (1, 2)      NO, 2 * 2 <= 10
+# - INSERT (2, 4)      NO, 4 * 2 <= 10
+# - INSERT (3, 6)      YES, 6 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is($result, qq(3|6),
+	'check initial data copy from table tab_rowfilter_virtual');
+
 # The following commands are executed after CREATE SUBSCRIPTION, so these SQL
 # commands are for testing normal logical replication behavior.
 #
@@ -582,6 +607,8 @@
 	"INSERT INTO tab_rowfilter_child (a, b) VALUES (13, '13'), (17, '17')");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rowfilter_viaroot_part (a) VALUES (14), (15), (16)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (4, 3), (5, 7)");
 
 $node_publisher->wait_for_catchup($appname);
 
@@ -725,6 +752,15 @@
 	'check replicated rows to tab_rowfilter_inherited and tab_rowfilter_child'
 );
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (4, 3)      NO, 3 * 2 <= 10
+# - INSERT (5, 7)      YES, 7 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is( $result, qq(3|6
+5|7), 'check replicated rows to tab_rowfilter_virtual');
+
 # UPDATE the non-toasted column for table tab_rowfilter_toast
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_rowfilter_toast SET b = '1'");
diff --git a/src/test/subscription/t/031_column_list.pl b/src/test/subscription/t/031_column_list.pl
index 7a535e76b08..e859bcdf4eb 100644
--- a/src/test/subscription/t/031_column_list.pl
+++ b/src/test/subscription/t/031_column_list.pl
@@ -1209,7 +1209,7 @@
 # list) are considered to have the same column list.
 $node_publisher->safe_psql(
 	'postgres', qq(
-	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED);
+	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED, e int GENERATED ALWAYS AS (a + 2) VIRTUAL);
 	ALTER TABLE test_mix_4 DROP COLUMN c;
 
 	CREATE PUBLICATION pub_mix_7 FOR TABLE test_mix_4 (a, b);

base-commit: 65281391a937293db7fa747be218def0e9794550
-- 
2.48.1

From 521b99cc1108cf9c4ad178af1d517722bf84e029 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 27 Jan 2025 07:42:55 +0100
Subject: [PATCH v14 1/3] Virtual generated columns

This adds a new variant of generated columns that are computed on read
(like a view, unlike the existing stored generated columns, which are
computed on write, like a materialized view).

The syntax for the column definition is

    ... GENERATED ALWAYS AS (...) VIRTUAL

and VIRTUAL is also optional.  VIRTUAL is the default rather than
STORED to match various other SQL products.  (The SQL standard makes
no specification about this, but it also doesn't know about VIRTUAL or
STORED.)  (Also, virtual views are the default, rather than
materialized views.)

Virtual generated columns are stored in tuples as null values.  (A
very early version of this patch had the ambition to not store them at
all.  But so much stuff breaks or gets confused if you have tuples
where a column in the middle is completely missing.  This is a
compromise, and it still saves space over being forced to use stored
generated columns.  If we ever find a way to improve this, a bit of
pg_upgrade cleverness could allow for upgrades to a newer scheme.)

The capabilities and restrictions of virtual generated columns are
mostly the same as for stored generated columns.  In some cases, this
patch keeps virtual generated columns more restricted than they might
technically need to be, to keep the two kinds consistent.  Some of
that could maybe be relaxed later after separate careful
considerations.

Some functionality that is currently not supported, but could possibly
be added as incremental features, some easier than others:

- index on or using a virtual column
- hence also no unique constraints on virtual columns
- extended statistics on virtual columns
- foreign key constraints on virtual columns
- not-null constraints on virtual columns (check constraints are supported)
- ALTER TABLE / DROP EXPRESSION
- virtual column cannot have domain type
- virtual columns are not supported in logical replication

The tests in generated_virtual.sql have been copied over from
generated_stored.sql with the keyword replaced.  This way we can make
sure the behavior is mostly aligned, and the differences can be
visible.  Some tests for currently not supported features are
currently commented out.

Reviewed-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/a368248e-69e4-40be-9c07-6c3b5880b0a6@eisentraut.org

TODO: catversion
---
 contrib/pageinspect/expected/page.out         |  37 +
 contrib/pageinspect/sql/page.sql              |  19 +
 .../postgres_fdw/expected/postgres_fdw.out    |  81 +-
 contrib/postgres_fdw/sql/postgres_fdw.sql     |   9 +-
 doc/src/sgml/catalogs.sgml                    |   6 +-
 doc/src/sgml/ddl.sgml                         |  46 +-
 doc/src/sgml/ref/alter_table.sgml             |  15 +-
 doc/src/sgml/ref/create_foreign_table.sgml    |  11 +-
 doc/src/sgml/ref/create_table.sgml            |  22 +-
 doc/src/sgml/trigger.sgml                     |   4 +
 src/backend/access/common/tupdesc.c           |   3 +
 src/backend/access/heap/heapam_handler.c      |   2 +
 src/backend/catalog/heap.c                    |  23 +-
 src/backend/catalog/pg_publication.c          |  10 +-
 src/backend/commands/analyze.c                |   4 +
 src/backend/commands/indexcmds.c              |  33 +-
 src/backend/commands/publicationcmds.c        |   3 +
 src/backend/commands/statscmds.c              |  20 +-
 src/backend/commands/tablecmds.c              | 196 ++++-
 src/backend/commands/trigger.c                |  45 +-
 src/backend/executor/execExprInterp.c         |   4 +
 src/backend/executor/execMain.c               |   5 +-
 src/backend/executor/execUtils.c              |   4 +-
 src/backend/executor/nodeModifyTable.c        |  41 +-
 src/backend/parser/gram.y                     |  15 +-
 src/backend/parser/parse_relation.c           |   6 +-
 src/backend/parser/parse_utilcmd.c            |  16 +-
 src/backend/replication/pgoutput/pgoutput.c   |   3 +-
 src/backend/rewrite/rewriteHandler.c          | 133 ++-
 src/backend/utils/cache/relcache.c            |   3 +
 src/bin/pg_dump/pg_dump.c                     |   3 +
 src/bin/pg_dump/t/002_pg_dump.pl              |   6 +-
 src/bin/psql/describe.c                       |   6 +
 src/include/access/tupdesc.h                  |   1 +
 src/include/catalog/heap.h                    |   1 +
 src/include/catalog/pg_attribute.h            |   1 +
 src/include/executor/nodeModifyTable.h        |   6 +-
 src/include/nodes/execnodes.h                 |   3 +
 src/include/nodes/parsenodes.h                |   1 +
 src/include/parser/kwlist.h                   |   1 +
 src/include/rewrite/rewriteHandler.h          |   2 +
 src/pl/plperl/expected/plperl_trigger.out     |   7 +-
 src/pl/plperl/plperl.c                        |   3 +
 src/pl/plperl/sql/plperl_trigger.sql          |   3 +-
 src/pl/plpython/expected/plpython_trigger.out |   7 +-
 src/pl/plpython/plpy_typeio.c                 |   3 +
 src/pl/plpython/sql/plpython_trigger.sql      |   3 +-
 src/pl/tcl/expected/pltcl_trigger.out         |  19 +-
 src/pl/tcl/pltcl.c                            |   3 +
 src/pl/tcl/sql/pltcl_trigger.sql              |   3 +-
 .../regress/expected/collate.icu.utf8.out     |  20 +
 .../regress/expected/create_table_like.out    |  23 +-
 src/test/regress/expected/fast_default.out    |  12 +
 .../regress/expected/generated_stored.out     |  21 +-
 ...rated_stored.out => generated_virtual.out} | 754 ++++++++----------
 src/test/regress/expected/publication.out     |  27 +-
 src/test/regress/expected/rowsecurity.out     |  29 +
 src/test/regress/expected/stats_ext.out       |  23 +
 src/test/regress/parallel_schedule            |   2 +-
 src/test/regress/sql/collate.icu.utf8.sql     |  15 +
 src/test/regress/sql/create_table_like.sql    |   2 +-
 src/test/regress/sql/fast_default.sql         |  11 +
 src/test/regress/sql/generated_stored.sql     |  12 +-
 ...rated_stored.sql => generated_virtual.sql} | 300 +++----
 src/test/regress/sql/publication.sql          |  22 +-
 src/test/regress/sql/rowsecurity.sql          |  27 +
 src/test/regress/sql/stats_ext.sql            |  14 +
 src/test/subscription/t/011_generated.pl      |  39 +-
 src/test/subscription/t/028_row_filter.pl     |  38 +-
 src/test/subscription/t/031_column_list.pl    |   2 +-
 70 files changed, 1529 insertions(+), 765 deletions(-)
 copy src/test/regress/expected/{generated_stored.out => generated_virtual.out} (72%)
 copy src/test/regress/sql/{generated_stored.sql => generated_virtual.sql} (74%)

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 3fd3869c82a..e42fd9747fd 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -208,6 +208,43 @@ select tuple_data_split('test8'::regclass, t_data, t_infomask, t_infomask2, t_bi
 (1 row)
 
 drop table test8;
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+      raw_flags      | t_bits |       t_data       
+---------------------+--------+--------------------
+ {HEAP_XMAX_INVALID} |        | \x0002020000040400
+(1 row)
+
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+       tuple_data_split        
+-------------------------------
+ {"\\x00020200","\\x00040400"}
+(1 row)
+
+drop table test9s;
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+            raw_flags             |  t_bits  |   t_data   
+----------------------------------+----------+------------
+ {HEAP_HASNULL,HEAP_XMAX_INVALID} | 10000000 | \x00020200
+(1 row)
+
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+   tuple_data_split   
+----------------------
+ {"\\x00020200",NULL}
+(1 row)
+
+drop table test9v;
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 346e4ee142c..c75fe1147f6 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -84,6 +84,25 @@ CREATE TEMP TABLE test1 (a int, b int);
     from heap_page_items(get_raw_page('test8', 0));
 drop table test8;
 
+-- check storage of generated columns
+-- stored
+create table test9s (a int not null, b int generated always as (a * 2) stored);
+insert into test9s values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9s', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9s'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9s', 0));
+drop table test9s;
+
+-- virtual
+create table test9v (a int not null, b int generated always as (a * 2) virtual);
+insert into test9v values (131584);
+select raw_flags, t_bits, t_data
+    from heap_page_items(get_raw_page('test9v', 0)), lateral heap_tuple_infomask_flags(t_infomask, t_infomask2);
+select tuple_data_split('test9v'::regclass, t_data, t_infomask, t_infomask2, t_bits)
+    from heap_page_items(get_raw_page('test9v', 0));
+drop table test9v;
+
 -- Failure with incorrect page size
 -- Suppress the DETAIL message, to allow the tests to work across various
 -- page sizes.
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index 7e487cff2a4..daa3b1d7a6d 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -7395,65 +7395,68 @@ select * from rem1;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 1
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 explain (verbose, costs off)
 update grem1 set a = 22 where a = 2;
-                                     QUERY PLAN                                     
-------------------------------------------------------------------------------------
+                                       QUERY PLAN                                       
+----------------------------------------------------------------------------------------
  Update on public.grem1
-   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT WHERE ctid = $1
+   Remote SQL: UPDATE public.gloc1 SET a = $2, b = DEFAULT, c = DEFAULT WHERE ctid = $1
    ->  Foreign Scan on public.grem1
          Output: 22, ctid, grem1.*
-         Remote SQL: SELECT a, b, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
+         Remote SQL: SELECT a, b, c, ctid FROM public.gloc1 WHERE ((a = 2)) FOR UPDATE
 (5 rows)
 
 update grem1 set a = 22 where a = 2;
 select * from gloc1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c 
+----+----+---
+  1 |  2 |  
+ 22 | 44 |  
 (2 rows)
 
 select * from grem1;
- a  | b  
-----+----
-  1 |  2
- 22 | 44
+ a  | b  | c  
+----+----+----
+  1 |  2 |  3
+ 22 | 44 | 66
 (2 rows)
 
 delete from grem1;
 -- test copy from
 copy grem1 from stdin;
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
@@ -7461,28 +7464,28 @@ delete from grem1;
 alter server loopback options (add batch_size '10');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
-                            QUERY PLAN                             
--------------------------------------------------------------------
+                                  QUERY PLAN                                   
+-------------------------------------------------------------------------------
  Insert on public.grem1
-   Remote SQL: INSERT INTO public.gloc1(a, b) VALUES ($1, DEFAULT)
+   Remote SQL: INSERT INTO public.gloc1(a, b, c) VALUES ($1, DEFAULT, DEFAULT)
    Batch Size: 10
    ->  Values Scan on "*VALUES*"
-         Output: "*VALUES*".column1, NULL::integer
+         Output: "*VALUES*".column1, NULL::integer, NULL::integer
 (5 rows)
 
 insert into grem1 (a) values (1), (2);
 select * from gloc1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 |  
+ 2 | 4 |  
 (2 rows)
 
 select * from grem1;
- a | b 
----+---
- 1 | 2
- 2 | 4
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
+ 2 | 4 | 6
 (2 rows)
 
 delete from grem1;
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index b58ab6ee586..1598d9e0862 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1859,12 +1859,15 @@ CREATE VIEW rw_view AS SELECT * FROM parent_tbl WHERE a < 5 WITH CHECK OPTION;
 -- ===================================================================
 create table gloc1 (
   a int,
-  b int generated always as (a * 2) stored);
+  b int generated always as (a * 2) stored,
+  c int
+);
 alter table gloc1 set (autovacuum_enabled = 'false');
 create foreign table grem1 (
   a int,
-  b int generated always as (a * 2) stored)
-  server loopback options(table_name 'gloc1');
+  b int generated always as (a * 2) stored,
+  c int generated always as (a * 3) virtual
+) server loopback options(table_name 'gloc1');
 explain (verbose, costs off)
 insert into grem1 (a) values (1), (2);
 insert into grem1 (a) values (1), (2);
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 088fb175cce..ee59a7e15d0 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1307,8 +1307,10 @@ <title><structname>pg_attribute</structname> Columns</title>
       </para>
       <para>
        If a zero byte (<literal>''</literal>), then not a generated column.
-       Otherwise, <literal>s</literal> = stored.  (Other values might be added
-       in the future.)
+       Otherwise, <literal>s</literal> = stored, <literal>v</literal> =
+       virtual.  A stored generated column is physically stored like a normal
+       column.  A virtual generated column is physically stored as a null
+       value, with the actual value being computed at run time.
       </para></entry>
      </row>
 
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 7ff39ae8c67..ae156b6b1cd 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -361,7 +361,6 @@ <title>Generated Columns</title>
    storage and is computed when it is read.  Thus, a virtual generated column
    is similar to a view and a stored generated column is similar to a
    materialized view (except that it is always updated automatically).
-   <productname>PostgreSQL</productname> currently implements only stored generated columns.
   </para>
 
   <para>
@@ -371,12 +370,12 @@ <title>Generated Columns</title>
 CREATE TABLE people (
     ...,
     height_cm numeric,
-    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54) STORED</emphasis>
+    height_in numeric <emphasis>GENERATED ALWAYS AS (height_cm / 2.54)</emphasis>
 );
 </programlisting>
-   The keyword <literal>STORED</literal> must be specified to choose the
-   stored kind of generated column.  See <xref linkend="sql-createtable"/> for
-   more details.
+   A generated column is by default of the virtual kind.  Use the keywords
+   <literal>VIRTUAL</literal> or <literal>STORED</literal> to make the choice
+   explicit.  See <xref linkend="sql-createtable"/> for more details.
   </para>
 
   <para>
@@ -442,12 +441,18 @@ <title>Generated Columns</title>
       <listitem>
        <para>
         If a parent column is a generated column, its child column must also
-        be a generated column; however, the child column can have a
-        different generation expression.  The generation expression that is
+        be a generated column of the same kind (stored or virtual); however,
+        the child column can have a different generation expression.
+       </para>
+
+       <para>
+        For stored generated columns, the generation expression that is
         actually applied during insert or update of a row is the one
-        associated with the table that the row is physically in.
-        (This is unlike the behavior for column defaults: for those, the
-        default value associated with the table named in the query applies.)
+        associated with the table that the row is physically in.  (This is
+        unlike the behavior for column defaults: for those, the default value
+        associated with the table named in the query applies.)  For virtual
+        generated columns, the generation expression of the table named in the
+        query applies when a table is read.
        </para>
       </listitem>
       <listitem>
@@ -502,6 +507,26 @@ <title>Generated Columns</title>
       particular role can read from a generated column but not from the
       underlying base columns.
      </para>
+
+     <para>
+      For virtual generated columns, this is only fully secure if the
+      generation expression uses only leakproof functions (see <xref
+      linkend="sql-createfunction"/>), but this is not enforced by the system.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Privileges of functions used in generation expressions are checked when
+      the expression is actually executed, on write or read respectively, as
+      if the generation expression had been called directly from the query
+      using the generated column.  The user of a generated column must have
+      permissions to call all functions used by the generation expression.
+      Functions in the generation expression are executed with the privileges
+      of the user executing the query or the function owner, depending on
+      whether the functions are defined as <literal>SECURITY INVOKER</literal>
+      or <literal>SECURITY DEFINER</literal>.
+      <!-- matches create_view.sgml -->
+     </para>
     </listitem>
     <listitem>
      <para>
@@ -519,6 +544,7 @@ <title>Generated Columns</title>
       <link linkend="sql-createpublication-params-with-publish-generated-columns">
       <literal>publish_generated_columns</literal></link> or by including them
       in the column list of the <command>CREATE PUBLICATION</command> command.
+      This is currently only supported for stored generated columns.
       See <xref linkend="logical-replication-gencols"/> for details.
      </para>
     </listitem>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index f9576da435e..8e56b8e59b0 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -102,7 +102,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -264,8 +264,8 @@ <title>Description</title>
     <listitem>
      <para>
       This form replaces the expression of a generated column.  Existing data
-      in the column is rewritten and all the future changes will apply the new
-      generation expression.
+      in a stored generated column is rewritten and all the future changes
+      will apply the new generation expression.
      </para>
     </listitem>
    </varlistentry>
@@ -279,10 +279,15 @@ <title>Description</title>
       longer apply the generation expression.
      </para>
 
+     <para>
+      This form is currently only supported for stored generated columns (not
+      virtual ones).
+     </para>
+
      <para>
       If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the
-      column is not a stored generated column, no error is thrown.  In this
-      case a notice is issued instead.
+      column is not a generated column, no error is thrown.  In this case a
+      notice is issued instead.
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml
index 0dcd9ca6f87..e0b0e075c2c 100644
--- a/doc/src/sgml/ref/create_foreign_table.sgml
+++ b/doc/src/sgml/ref/create_foreign_table.sgml
@@ -47,7 +47,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED }
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] }
 [ ENFORCED | NOT ENFORCED ]
 
 <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase>
@@ -283,7 +283,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -292,10 +292,13 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read.  (The foreign-data wrapper will see it as a
+      null value in new rows and may choose to store it as a null value or
+      ignore it altogether.)  When <literal>STORED</literal> is specified, the
       column will be computed on write.  (The computed value will be presented
       to the foreign-data wrapper for storage and must be returned on
-      reading.)
+      reading.)  <literal>VIRTUAL</literal> is the default.
      </para>
 
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 2237321cb4f..060793404f1 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -65,7 +65,7 @@
   NULL |
   CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
-  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
+  GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ] |
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
@@ -725,8 +725,9 @@ <title>Parameters</title>
         <term><literal>INCLUDING GENERATED</literal></term>
         <listitem>
          <para>
-          Any generation expressions of copied column definitions will be
-          copied.  By default, new columns will be regular base columns.
+          Any generation expressions as well as the stored/virtual choice of
+          copied column definitions will be copied.  By default, new columns
+          will be regular base columns.
          </para>
         </listitem>
        </varlistentry>
@@ -907,7 +908,7 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry id="sql-createtable-parms-generated-stored">
-    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term>
+    <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) [ STORED | VIRTUAL ]</literal><indexterm><primary>generated column</primary></indexterm></term>
     <listitem>
      <para>
       This clause creates the column as a <firstterm>generated
@@ -916,8 +917,11 @@ <title>Parameters</title>
      </para>
 
      <para>
-      The keyword <literal>STORED</literal> is required to signify that the
-      column will be computed on write and will be stored on disk.
+      When <literal>VIRTUAL</literal> is specified, the column will be
+      computed when it is read, and it will not occupy any storage.  When
+      <literal>STORED</literal> is specified, the column will be computed on
+      write and will be stored on disk.  <literal>VIRTUAL</literal> is the
+      default.
      </para>
 
      <para>
@@ -2489,9 +2493,9 @@ <title>Multiple Identity Columns</title>
    <title>Generated Columns</title>
 
    <para>
-    The option <literal>STORED</literal> is not standard but is also used by
-    other SQL implementations.  The SQL standard does not specify the storage
-    of generated columns.
+    The options <literal>STORED</literal> and <literal>VIRTUAL</literal> are
+    not standard but are also used by other SQL implementations.  The SQL
+    standard does not specify the storage of generated columns.
    </para>
   </refsect2>
 
diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml
index c3c0faf7a1b..e9214dcf1b1 100644
--- a/doc/src/sgml/trigger.sgml
+++ b/doc/src/sgml/trigger.sgml
@@ -293,6 +293,10 @@ <title>Overview of Trigger Behavior</title>
     <literal>BEFORE</literal> trigger.  Changes to the value of a generated
     column in a <literal>BEFORE</literal> trigger are ignored and will be
     overwritten.
+    Virtual generated columns are never computed when triggers fire.  In the C
+    language interface, their content is undefined in a trigger function.
+    Higher-level programming languages should prevent access to virtual
+    generated columns in triggers.
    </para>
 
    <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index fe197447912..ed2195f14b2 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -342,6 +342,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 
 		cpy->has_not_null = constr->has_not_null;
 		cpy->has_generated_stored = constr->has_generated_stored;
+		cpy->has_generated_virtual = constr->has_generated_virtual;
 
 		if ((cpy->num_defval = constr->num_defval) > 0)
 		{
@@ -640,6 +641,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (constr1->has_generated_stored != constr2->has_generated_stored)
 			return false;
+		if (constr1->has_generated_virtual != constr2->has_generated_virtual)
+			return false;
 		n = constr1->num_defval;
 		if (n != (int) constr2->num_defval)
 			return false;
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index a4003cf59e1..c0bec014154 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2047,6 +2047,8 @@ heapam_relation_needs_toast_table(Relation rel)
 
 		if (att->attisdropped)
 			continue;
+		if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			continue;
 		data_length = att_align_nominal(data_length, att->attalign);
 		if (att->attlen > 0)
 		{
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 57ef466acce..956f196fc95 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -507,7 +507,7 @@ CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind,
 						   TupleDescAttr(tupdesc, i)->atttypid,
 						   TupleDescAttr(tupdesc, i)->attcollation,
 						   NIL, /* assume we're creating a new rowtype */
-						   flags);
+						   flags | (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL ? CHKATYPE_IS_VIRTUAL : 0));
 	}
 }
 
@@ -582,6 +582,17 @@ CheckAttributeType(const char *attname,
 	}
 	else if (att_typtype == TYPTYPE_DOMAIN)
 	{
+		/*
+		 * Prevent virtual generated columns from having a domain type.  We
+		 * would have to enforce domain constraints when columns underlying
+		 * the generated column change.  This could possibly be implemented,
+		 * but it's not.
+		 */
+		if (flags & CHKATYPE_IS_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("virtual generated column \"%s\" cannot have a domain type", attname));
+
 		/*
 		 * If it's a domain, recurse to check its base type.
 		 */
@@ -2553,6 +2564,11 @@ AddRelationNewConstraints(Relation rel,
 						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						errmsg("cannot add not-null constraint on system column \"%s\"",
 							   strVal(linitial(cdef->keys))));
+			/* TODO: see transformColumnDefinition() */
+			if (get_attgenerated(RelationGetRelid(rel), colnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						errmsg("not-null constraints are not supported on virtual generated columns"));
 
 			/*
 			 * If the column already has a not-null constraint, we don't want
@@ -2868,6 +2884,11 @@ AddRelationNotNullConstraints(Relation rel, List *constraints,
 					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					errmsg("cannot add not-null constraint on system column \"%s\"",
 						   strVal(linitial(constr->keys))));
+		/* TODO: see transformColumnDefinition() */
+		if (get_attgenerated(RelationGetRelid(rel), attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("not-null constraints are not supported on virtual generated columns"));
 
 		/*
 		 * A column can only have one not-null constraint, so discard any
diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c
index 41ffd494c81..d6f94db5d99 100644
--- a/src/backend/catalog/pg_publication.c
+++ b/src/backend/catalog/pg_publication.c
@@ -546,7 +546,8 @@ publication_add_relation(Oid pubid, PublicationRelInfo *pri,
  * pub_collist_validate
  *		Process and validate the 'columns' list and ensure the columns are all
  *		valid to use for a publication.  Checks for and raises an ERROR for
- * 		any unknown columns, system columns, or duplicate columns.
+ *		any unknown columns, system columns, duplicate columns, or virtual
+ *		generated columns.
  *
  * Looks up each column's attnum and returns a 0-based Bitmapset of the
  * corresponding attnums.
@@ -556,6 +557,7 @@ pub_collist_validate(Relation targetrel, List *columns)
 {
 	Bitmapset  *set = NULL;
 	ListCell   *lc;
+	TupleDesc	tupdesc = RelationGetDescr(targetrel);
 
 	foreach(lc, columns)
 	{
@@ -574,6 +576,12 @@ pub_collist_validate(Relation targetrel, List *columns)
 					errmsg("cannot use system column \"%s\" in publication column list",
 						   colname));
 
+		if (TupleDescAttr(tupdesc, attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+					errmsg("cannot use virtual generated column \"%s\" in publication column list",
+						   colname));
+
 		if (bms_is_member(attnum, set))
 			ereport(ERROR,
 					errcode(ERRCODE_DUPLICATE_OBJECT),
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index f8da32e9aef..e5ab207d2ec 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -1039,6 +1039,10 @@ examine_attribute(Relation onerel, int attnum, Node *index_expr)
 	if (attr->attisdropped)
 		return NULL;
 
+	/* Don't analyze virtual generated columns */
+	if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		return NULL;
+
 	/*
 	 * Get attstattarget value.  Set to -1 if null.  (Analyze functions expect
 	 * -1 to mean use default_statistics_target; see for example
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 5b1753d4681..f8d3ea820e1 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -1110,6 +1110,9 @@ DefineIndex(Oid tableId,
 	/*
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
+	 *
+	 * Also disallow virtual generated columns in indexes (use expression
+	 * index instead).
 	 */
 	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
@@ -1119,14 +1122,24 @@ DefineIndex(Oid tableId,
 			ereport(ERROR,
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("index creation on system columns is not supported")));
+
+
+		if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 stmt->isconstraint ?
+					 errmsg("unique constraints on virtual generated columns are not supported") :
+					 errmsg("indexes on virtual generated columns are not supported")));
 	}
 
 	/*
-	 * Also check for system columns used in expressions or predicates.
+	 * Also check for system and generated columns used in expressions or
+	 * predicates.
 	 */
 	if (indexInfo->ii_Expressions || indexInfo->ii_Predicate)
 	{
 		Bitmapset  *indexattrs = NULL;
+		int			j;
 
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
@@ -1139,6 +1152,24 @@ DefineIndex(Oid tableId,
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("index creation on system columns is not supported")));
 		}
+
+		/*
+		 * XXX Virtual generated columns in index expressions or predicates
+		 * could be supported, but it needs support in
+		 * RelationGetIndexExpressions() and RelationGetIndexPredicate().
+		 */
+		j = -1;
+		while ((j = bms_next_member(indexattrs, j)) >= 0)
+		{
+			AttrNumber	attno = j + FirstLowInvalidHeapAttributeNumber;
+
+			if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 stmt->isconstraint ?
+						 errmsg("unique constraints on virtual generated columns are not supported") :
+						 errmsg("indexes on virtual generated columns are not supported")));
+		}
 	}
 
 	/* Is index safe for others to ignore?  See set_indexsafe_procflags() */
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 951ffabb656..801560c8fdc 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -38,6 +38,7 @@
 #include "parser/parse_clause.h"
 #include "parser/parse_collate.h"
 #include "parser/parse_relation.h"
+#include "rewrite/rewriteHandler.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
@@ -689,6 +690,8 @@ TransformPubWhereClauses(List *tables, const char *queryString,
 		/* Fix up collation information */
 		assign_expr_collations(pstate, whereclause);
 
+		whereclause = expand_generated_columns_in_expr(whereclause, pri->relation, 1);
+
 		/*
 		 * We allow only simple expressions in row filters. See
 		 * check_simple_rowfilter_expr_walker.
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index a817821bf6d..e24d540cd45 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -246,6 +246,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (attForm->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(attForm->atttypid, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -269,6 +275,12 @@ CreateStatistics(CreateStatsStmt *stmt)
 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 						 errmsg("statistics creation on system columns is not supported")));
 
+			/* Disallow use of virtual generated columns in extended stats */
+			if (get_attgenerated(relid, var->varattno) == ATTRIBUTE_GENERATED_VIRTUAL)
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("statistics creation on virtual generated columns is not supported")));
+
 			/* Disallow data types without a less-than operator */
 			type = lookup_type_cache(var->vartype, TYPECACHE_LT_OPR);
 			if (type->lt_opr == InvalidOid)
@@ -290,7 +302,6 @@ CreateStatistics(CreateStatsStmt *stmt)
 
 			Assert(expr != NULL);
 
-			/* Disallow expressions referencing system attributes. */
 			pull_varattnos(expr, 1, &attnums);
 
 			k = -1;
@@ -298,10 +309,17 @@ CreateStatistics(CreateStatsStmt *stmt)
 			{
 				AttrNumber	attnum = k + FirstLowInvalidHeapAttributeNumber;
 
+				/* Disallow expressions referencing system attributes. */
 				if (attnum <= 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("statistics creation on system columns is not supported")));
+
+				/* Disallow use of virtual generated columns in extended stats */
+				if (get_attgenerated(relid, attnum) == ATTRIBUTE_GENERATED_VIRTUAL)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("statistics creation on virtual generated columns is not supported")));
 			}
 
 			/*
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 18f64db6e39..94660e4bd45 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -3039,6 +3039,15 @@ MergeAttributes(List *columns, const List *supers, char relpersistence,
 									 errhint("A child table column cannot be generated unless its parent column is.")));
 					}
 
+					if (coldef->generated && restdef->generated && coldef->generated != restdef->generated)
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+								 errmsg("column \"%s\" inherits from generated column of different kind",
+										restdef->colname),
+								 errdetail("Parent column is %s, child column is %s.",
+										   coldef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+										   restdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 					/*
 					 * Override the parent's default value for this column
 					 * (coldef->cooked_default) with the partition's local
@@ -3324,6 +3333,15 @@ MergeChildAttribute(List *inh_columns, int exist_attno, int newcol_attno, const
 					 errhint("A child table column cannot be generated unless its parent column is.")));
 	}
 
+	if (inhdef->generated && newdef->generated && newdef->generated != inhdef->generated)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+				 errmsg("column \"%s\" inherits from generated column of different kind",
+						inhdef->colname),
+				 errdetail("Parent column is %s, child column is %s.",
+						   inhdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+						   newdef->generated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 	/*
 	 * If new def has a default, override previous default
 	 */
@@ -6130,7 +6148,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
 		{
 			case CONSTR_CHECK:
 				needscan = true;
-				con->qualstate = ExecPrepareExpr((Expr *) con->qual, estate);
+				con->qualstate = ExecPrepareExpr((Expr *) expand_generated_columns_in_expr(con->qual, newrel ? newrel : oldrel, 1), estate);
 				break;
 			case CONSTR_FOREIGN:
 				/* Nothing to do here */
@@ -7308,7 +7326,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 * DEFAULT value outside of the heap.  This may be disabled inside
 		 * AddRelationNewConstraints if the optimization cannot be applied.
 		 */
-		rawEnt->missingMode = (!colDef->generated);
+		rawEnt->missingMode = (colDef->generated != ATTRIBUTE_GENERATED_STORED);
 
 		rawEnt->generated = colDef->generated;
 
@@ -7785,6 +7803,14 @@ ATExecSetNotNull(List **wqueue, Relation rel, char *conName, char *colName,
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/* TODO: see transformColumnDefinition() */
+	if (TupleDescAttr(RelationGetDescr(rel), attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("not-null constraints are not supported on virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
 	/* See if there's already a constraint */
 	tuple = findNotNullConstraintAttnum(RelationGetRelid(rel), attnum);
 	if (HeapTupleIsValid(tuple))
@@ -8411,6 +8437,8 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	HeapTuple	tuple;
 	Form_pg_attribute attTup;
 	AttrNumber	attnum;
+	char		attgenerated;
+	bool		rewrite;
 	Oid			attrdefoid;
 	ObjectAddress address;
 	Expr	   *defval;
@@ -8425,36 +8453,70 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 						colName, RelationGetRelationName(rel))));
 
 	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
-	attnum = attTup->attnum;
 
+	attnum = attTup->attnum;
 	if (attnum <= 0)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	attgenerated = attTup->attgenerated;
+	if (!attgenerated)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 				 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 						colName, RelationGetRelationName(rel))));
-	ReleaseSysCache(tuple);
 
 	/*
-	 * Clear all the missing values if we're rewriting the table, since this
-	 * renders them pointless.
+	 * TODO: This could be done, just need to recheck any constraints
+	 * afterwards.
 	 */
-	RelationClearMissing(rel);
-
-	/* make sure we don't conflict with later attribute modifications */
-	CommandCounterIncrement();
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		rel->rd_att->constr && rel->rd_att->constr->num_check > 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
 
 	/*
-	 * Find everything that depends on the column (constraints, indexes, etc),
-	 * and record enough information to let us recreate the objects after
-	 * rewrite.
+	 * We need to prevent this because a change of expression could affect a
+	 * row filter and inject expressions that are not permitted in a row
+	 * filter.  XXX We could try to have a more precise check to catch only
+	 * publications with row filters, or even re-verify the row filter
+	 * expressions.
 	 */
-	RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL &&
+		GetRelationPublications(RelationGetRelid(rel)) != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	rewrite = (attgenerated == ATTRIBUTE_GENERATED_STORED);
+
+	ReleaseSysCache(tuple);
+
+	if (rewrite)
+	{
+		/*
+		 * Clear all the missing values if we're rewriting the table, since
+		 * this renders them pointless.
+		 */
+		RelationClearMissing(rel);
+
+		/* make sure we don't conflict with later attribute modifications */
+		CommandCounterIncrement();
+
+		/*
+		 * Find everything that depends on the column (constraints, indexes,
+		 * etc), and record enough information to let us recreate the objects
+		 * after rewrite.
+		 */
+		RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
+	}
 
 	/*
 	 * Drop the dependency records of the GENERATED expression, in particular
@@ -8483,7 +8545,7 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	rawEnt->attnum = attnum;
 	rawEnt->raw_default = newExpr;
 	rawEnt->missingMode = false;
-	rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
+	rawEnt->generated = attgenerated;
 
 	/* Store the generated expression */
 	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
@@ -8492,16 +8554,19 @@ ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
 	/* Make above new expression visible */
 	CommandCounterIncrement();
 
-	/* Prepare for table rewrite */
-	defval = (Expr *) build_column_default(rel, attnum);
+	if (rewrite)
+	{
+		/* Prepare for table rewrite */
+		defval = (Expr *) build_column_default(rel, attnum);
 
-	newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
-	newval->attnum = attnum;
-	newval->expr = expression_planner(defval);
-	newval->is_generated = true;
+		newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
+		newval->attnum = attnum;
+		newval->expr = expression_planner(defval);
+		newval->is_generated = true;
 
-	tab->newvals = lappend(tab->newvals, newval);
-	tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+		tab->newvals = lappend(tab->newvals, newval);
+		tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
+	}
 
 	/* Drop any pg_statistic entry for the column */
 	RemoveStatistics(RelationGetRelid(rel), attnum);
@@ -8590,17 +8655,30 @@ ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMOD
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
-	if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
+	/*
+	 * TODO: This could be done, but it would need a table rewrite to
+	 * materialize the generated values.  Note that for the time being, we
+	 * still error with missing_ok, so that we don't silently leave the column
+	 * as generated.
+	 */
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns"),
+				 errdetail("Column \"%s\" of relation \"%s\" is a virtual generated column.",
+						   colName, RelationGetRelationName(rel))));
+
+	if (!attTup->attgenerated)
 	{
 		if (!missing_ok)
 			ereport(ERROR,
 					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-					 errmsg("column \"%s\" of relation \"%s\" is not a stored generated column",
+					 errmsg("column \"%s\" of relation \"%s\" is not a generated column",
 							colName, RelationGetRelationName(rel))));
 		else
 		{
 			ereport(NOTICE,
-					(errmsg("column \"%s\" of relation \"%s\" is not a stored generated column, skipping",
+					(errmsg("column \"%s\" of relation \"%s\" is not a generated column, skipping",
 							colName, RelationGetRelationName(rel))));
 			heap_freetuple(tuple);
 			table_close(attrelation, RowExclusiveLock);
@@ -8743,6 +8821,16 @@ ATExecSetStatistics(Relation rel, const char *colName, int16 colNum, Node *newVa
 				 errmsg("cannot alter system column \"%s\"",
 						colName)));
 
+	/*
+	 * Prevent this as long as the ANALYZE code skips virtual generated
+	 * columns.
+	 */
+	if (attrtuple->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter statistics on virtual generated column \"%s\"",
+						colName)));
+
 	if (rel->rd_rel->relkind == RELKIND_INDEX ||
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_INDEX)
 	{
@@ -9925,6 +10013,19 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 						 errmsg("invalid %s action for foreign key constraint containing generated column",
 								"ON DELETE")));
 		}
+
+		/*
+		 * FKs on virtual columns are not supported.  This would require
+		 * various additional support in ri_triggers.c, including special
+		 * handling in ri_NullCheck(), ri_KeysEqual(),
+		 * RI_FKey_fk_upd_check_required() (since all virtual columns appear
+		 * as NULL there).  Also not really practical as long as you can't
+		 * index virtual columns.
+		 */
+		if (attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("foreign key constraints on virtual generated columns are not supported")));
 	}
 
 	/*
@@ -12289,7 +12390,7 @@ QueueCheckConstraintValidation(List **wqueue, Relation conrel, Relation rel,
 	val = SysCacheGetAttrNotNull(CONSTROID, contuple,
 								 Anum_pg_constraint_conbin);
 	conbin = TextDatumGetCString(val);
-	newcon->qual = (Node *) stringToNode(conbin);
+	newcon->qual = expand_generated_columns_in_expr(stringToNode(conbin), rel, 1);
 
 	/* Find or create work queue entry for this table */
 	tab = ATGetQueueEntry(wqueue, rel);
@@ -13467,8 +13568,12 @@ ATPrepAlterColumnType(List **wqueue,
 					   list_make1_oid(rel->rd_rel->reltype),
 					   0);
 
-	if (tab->relkind == RELKIND_RELATION ||
-		tab->relkind == RELKIND_PARTITIONED_TABLE)
+	if (attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+	{
+		/* do nothing */
+	}
+	else if (tab->relkind == RELKIND_RELATION ||
+			 tab->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		/*
 		 * Set up an expression to transform the old data value to the new
@@ -13541,11 +13646,12 @@ ATPrepAlterColumnType(List **wqueue,
 				 errmsg("\"%s\" is not a table",
 						RelationGetRelationName(rel))));
 
-	if (!RELKIND_HAS_STORAGE(tab->relkind))
+	if (!RELKIND_HAS_STORAGE(tab->relkind) || attTup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 	{
 		/*
-		 * For relations without storage, do this check now.  Regular tables
-		 * will check it later when the table is being rewritten.
+		 * For relations or columns without storage, do this check now.
+		 * Regular tables will check it later when the table is being
+		 * rewritten.
 		 */
 		find_composite_type_dependencies(rel->rd_rel->reltype, rel, NULL);
 	}
@@ -16534,6 +16640,14 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel, bool ispart
 						(errcode(ERRCODE_DATATYPE_MISMATCH),
 						 errmsg("column \"%s\" in child table must not be a generated column", parent_attname)));
 
+			if (parent_att->attgenerated && child_att->attgenerated && child_att->attgenerated != parent_att->attgenerated)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("column \"%s\" inherits from generated column of different kind", parent_attname),
+						 errdetail("Parent column is %s, child column is %s.",
+								   parent_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL",
+								   child_att->attgenerated == ATTRIBUTE_GENERATED_STORED ? "STORED" : "VIRTUAL")));
+
 			/*
 			 * Regular inheritance children are independent enough not to
 			 * inherit identity columns.  But partitions are integral part of
@@ -18781,8 +18895,11 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 						 parser_errposition(pstate, pelem->location)));
 
 			/*
-			 * Generated columns cannot work: They are computed after BEFORE
-			 * triggers, but partition routing is done before all triggers.
+			 * Stored generated columns cannot work: They are computed after
+			 * BEFORE triggers, but partition routing is done before all
+			 * triggers.  Maybe virtual generated columns could be made to
+			 * work, but then they would need to be handled as an expression
+			 * below.
 			 */
 			if (attform->attgenerated)
 				ereport(ERROR,
@@ -18864,9 +18981,12 @@ ComputePartitionAttrs(ParseState *pstate, Relation rel, List *partParams, AttrNu
 				}
 
 				/*
-				 * Generated columns cannot work: They are computed after
-				 * BEFORE triggers, but partition routing is done before all
-				 * triggers.
+				 * Stored generated columns cannot work: They are computed
+				 * after BEFORE triggers, but partition routing is done before
+				 * all triggers.  Virtual generated columns could probably
+				 * work, but it would require more work elsewhere (for example
+				 * SET EXPRESSION would need to check whether the column is
+				 * used in partition keys).  Seems safer to prohibit for now.
 				 */
 				i = -1;
 				while ((i = bms_next_member(expr_attrs, i)) >= 0)
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 7a5ffe32f60..97c087929f3 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -43,6 +43,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "pgstat.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "storage/lmgr.h"
 #include "utils/acl.h"
@@ -101,6 +102,7 @@ static void AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
 								  bool is_crosspart_update);
 static void AfterTriggerEnlargeQueryState(void);
 static bool before_stmt_triggers_fired(Oid relid, CmdType cmdType);
+static HeapTuple check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple);
 
 
 /*
@@ -641,7 +643,8 @@ CreateTriggerFiringOn(CreateTrigStmt *stmt, const char *queryString,
 					if (TRIGGER_FOR_BEFORE(tgtype) &&
 						var->varattno == 0 &&
 						RelationGetDescr(rel)->constr &&
-						RelationGetDescr(rel)->constr->has_generated_stored)
+						(RelationGetDescr(rel)->constr->has_generated_stored ||
+						 RelationGetDescr(rel)->constr->has_generated_virtual))
 						ereport(ERROR,
 								(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
 								 errmsg("BEFORE trigger's WHEN condition cannot reference NEW generated columns"),
@@ -2504,6 +2507,8 @@ ExecBRInsertTriggers(EState *estate, ResultRelInfo *relinfo,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, slot, false);
 
 			/*
@@ -3061,6 +3066,8 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,
 		}
 		else if (newtuple != oldtuple)
 		{
+			newtuple = check_modified_virtual_generated(RelationGetDescr(relinfo->ri_RelationDesc), newtuple);
+
 			ExecForceStoreHeapTuple(newtuple, newslot, false);
 
 			/*
@@ -3491,6 +3498,8 @@ TriggerEnabled(EState *estate, ResultRelInfo *relinfo,
 
 			oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
 			tgqual = stringToNode(trigger->tgqual);
+			tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_OLD_VARNO);
+			tgqual = expand_generated_columns_in_expr(tgqual, relinfo->ri_RelationDesc, PRS2_NEW_VARNO);
 			/* Change references to OLD and NEW to INNER_VAR and OUTER_VAR */
 			ChangeVarNodes(tgqual, PRS2_OLD_VARNO, INNER_VAR, 0);
 			ChangeVarNodes(tgqual, PRS2_NEW_VARNO, OUTER_VAR, 0);
@@ -6621,3 +6630,37 @@ pg_trigger_depth(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_INT32(MyTriggerDepth);
 }
+
+/*
+ * Check whether a trigger modified a virtual generated column and replace the
+ * value with null if so.
+ *
+ * We need to check this so that we don't end up storing a non-null value in a
+ * virtual generated column.
+ *
+ * We don't need to check for stored generated columns, since those will be
+ * overwritten later anyway.
+ */
+static HeapTuple
+check_modified_virtual_generated(TupleDesc tupdesc, HeapTuple tuple)
+{
+	if (!(tupdesc->constr && tupdesc->constr->has_generated_virtual))
+		return tuple;
+
+	for (int i = 0; i < tupdesc->natts; i++)
+	{
+		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+		{
+			if (!heap_attisnull(tuple, i + 1, tupdesc))
+			{
+				int			replCol = i + 1;
+				Datum		replValue = 0;
+				bool		replIsnull = true;
+
+				tuple = heap_modify_tuple_by_cols(tuple, tupdesc, 1, &replCol, &replValue, &replIsnull);
+			}
+		}
+	}
+
+	return tuple;
+}
diff --git a/src/backend/executor/execExprInterp.c b/src/backend/executor/execExprInterp.c
index 09f6a5f14c1..1c3477b03c9 100644
--- a/src/backend/executor/execExprInterp.c
+++ b/src/backend/executor/execExprInterp.c
@@ -2324,6 +2324,10 @@ CheckVarSlotCompatibility(TupleTableSlot *slot, int attnum, Oid vartype)
 
 		attr = TupleDescAttr(slot_tupdesc, attnum - 1);
 
+		/* Internal error: somebody forgot to expand it. */
+		if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			elog(ERROR, "unexpected virtual generated column reference");
+
 		if (attr->attisdropped)
 			ereport(ERROR,
 					(errcode(ERRCODE_UNDEFINED_COLUMN),
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 604cb0625b8..044b4e9742a 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1775,6 +1775,7 @@ ExecRelCheck(ResultRelInfo *resultRelInfo,
 				continue;
 
 			checkconstr = stringToNode(check[i].ccbin);
+			checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1);
 			resultRelInfo->ri_ConstraintExprs[i] =
 				ExecPrepareExpr(checkconstr, estate);
 		}
@@ -2322,7 +2323,9 @@ ExecBuildSlotValueDescription(Oid reloid,
 
 		if (table_perm || column_perm)
 		{
-			if (slot->tts_isnull[i])
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				val = "virtual";
+			else if (slot->tts_isnull[i])
 				val = "null";
 			else
 			{
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 00564985668..123d3c79b43 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1383,8 +1383,8 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (relinfo->ri_GeneratedExprsU == NULL)
-		ExecInitStoredGenerated(relinfo, estate, CMD_UPDATE);
+	if (!relinfo->ri_Generated_valid)
+		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index bc82e035ba2..2d490cf7ca5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -391,11 +391,14 @@ ExecCheckTIDVisible(EState *estate,
 }
 
 /*
- * Initialize to compute stored generated columns for a tuple
+ * Initialize generated columns handling for a tuple
+ *
+ * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI or
+ * ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
+ * This is used only for stored generated columns.
  *
- * This fills the resultRelInfo's ri_GeneratedExprsI/ri_NumGeneratedNeededI
- * or ri_GeneratedExprsU/ri_NumGeneratedNeededU fields, depending on cmdtype.
  * If cmdType == CMD_UPDATE, the ri_extraUpdatedCols field is filled too.
+ * This is used by both stored and virtual generated columns.
  *
  * Note: usually, a given query would need only one of ri_GeneratedExprsI and
  * ri_GeneratedExprsU per result rel; but MERGE can need both, and so can
@@ -403,9 +406,9 @@ ExecCheckTIDVisible(EState *estate,
  * UPDATE and INSERT actions.
  */
 void
-ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-						EState *estate,
-						CmdType cmdtype)
+ExecInitGenerated(ResultRelInfo *resultRelInfo,
+				  EState *estate,
+				  CmdType cmdtype)
 {
 	Relation	rel = resultRelInfo->ri_RelationDesc;
 	TupleDesc	tupdesc = RelationGetDescr(rel);
@@ -416,7 +419,7 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 	MemoryContext oldContext;
 
 	/* Nothing to do if no generated columns */
-	if (!(tupdesc->constr && tupdesc->constr->has_generated_stored))
+	if (!(tupdesc->constr && (tupdesc->constr->has_generated_stored || tupdesc->constr->has_generated_virtual)))
 		return;
 
 	/*
@@ -442,7 +445,9 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 
 	for (int i = 0; i < natts; i++)
 	{
-		if (TupleDescAttr(tupdesc, i)->attgenerated == ATTRIBUTE_GENERATED_STORED)
+		char		attgenerated = TupleDescAttr(tupdesc, i)->attgenerated;
+
+		if (attgenerated)
 		{
 			Expr	   *expr;
 
@@ -467,8 +472,11 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 			}
 
 			/* No luck, so prepare the expression for execution */
-			ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
-			ri_NumGeneratedNeeded++;
+			if (attgenerated == ATTRIBUTE_GENERATED_STORED)
+			{
+				ri_GeneratedExprs[i] = ExecPrepareExpr(expr, estate);
+				ri_NumGeneratedNeeded++;
+			}
 
 			/* If UPDATE, mark column in resultRelInfo->ri_extraUpdatedCols */
 			if (cmdtype == CMD_UPDATE)
@@ -478,6 +486,13 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		}
 	}
 
+	if (ri_NumGeneratedNeeded == 0)
+	{
+		/* didn't need it after all */
+		pfree(ri_GeneratedExprs);
+		ri_GeneratedExprs = NULL;
+	}
+
 	/* Save in appropriate set of fields */
 	if (cmdtype == CMD_UPDATE)
 	{
@@ -496,6 +511,8 @@ ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
+	resultRelInfo->ri_Generated_valid = true;
+
 	MemoryContextSwitchTo(oldContext);
 }
 
@@ -526,7 +543,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	if (cmdtype == CMD_UPDATE)
 	{
 		if (resultRelInfo->ri_GeneratedExprsU == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		if (resultRelInfo->ri_NumGeneratedNeededU == 0)
 			return;
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsU;
@@ -534,7 +551,7 @@ ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 	else
 	{
 		if (resultRelInfo->ri_GeneratedExprsI == NULL)
-			ExecInitStoredGenerated(resultRelInfo, estate, cmdtype);
+			ExecInitGenerated(resultRelInfo, estate, cmdtype);
 		/* Early exit is impossible given the prior Assert */
 		Assert(resultRelInfo->ri_NumGeneratedNeededI > 0);
 		ri_GeneratedExprs = resultRelInfo->ri_GeneratedExprsI;
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index d7f9c00c409..d3887628d46 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -636,7 +636,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
 %type <boolean> opt_unique_null_treatment
-%type <ival>	generated_when override_kind
+%type <ival>	generated_when override_kind opt_virtual_or_stored
 %type <partspec>	PartitionSpec OptPartitionSpec
 %type <partelem>	part_elem
 %type <list>		part_params
@@ -784,7 +784,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	UNLISTEN UNLOGGED UNTIL UPDATE USER USING
 
 	VACUUM VALID VALIDATE VALIDATOR VALUE_P VALUES VARCHAR VARIADIC VARYING
-	VERBOSE VERSION_P VIEW VIEWS VOLATILE
+	VERBOSE VERSION_P VIEW VIEWS VIRTUAL VOLATILE
 
 	WHEN WHERE WHITESPACE_P WINDOW WITH WITHIN WITHOUT WORK WRAPPER WRITE
 
@@ -3995,7 +3995,7 @@ ColConstraintElem:
 					n->location = @1;
 					$$ = (Node *) n;
 				}
-			| GENERATED generated_when AS '(' a_expr ')' STORED
+			| GENERATED generated_when AS '(' a_expr ')' opt_virtual_or_stored
 				{
 					Constraint *n = makeNode(Constraint);
 
@@ -4003,6 +4003,7 @@ ColConstraintElem:
 					n->generated_when = $2;
 					n->raw_expr = $5;
 					n->cooked_expr = NULL;
+					n->generated_kind = $7;
 					n->location = @1;
 
 					/*
@@ -4050,6 +4051,12 @@ generated_when:
 			| BY DEFAULT	{ $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
 		;
 
+opt_virtual_or_stored:
+			STORED			{ $$ = ATTRIBUTE_GENERATED_STORED; }
+			| VIRTUAL		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+			| /*EMPTY*/		{ $$ = ATTRIBUTE_GENERATED_VIRTUAL; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -17990,6 +17997,7 @@ unreserved_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHITESPACE_P
 			| WITHIN
@@ -18645,6 +18653,7 @@ bare_label_keyword:
 			| VERSION_P
 			| VIEW
 			| VIEWS
+			| VIRTUAL
 			| VOLATILE
 			| WHEN
 			| WHITESPACE_P
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 101fba34b18..04ecf64b1fc 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -712,7 +712,11 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
 						colname),
 				 parser_errposition(pstate, location)));
 
-	/* In generated column, no system column is allowed except tableOid */
+	/*
+	 * In generated column, no system column is allowed except tableOid.
+	 * (Required for stored generated, but we also do it for virtual generated
+	 * for now for consistency.)
+	 */
 	if (pstate->p_expr_kind == EXPR_KIND_GENERATED_COLUMN &&
 		attnum < InvalidAttrNumber && attnum != TableOidAttributeNumber)
 		ereport(ERROR,
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index ca028d2a66d..eb7716cd84c 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -889,7 +889,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 									column->colname, cxt->relation->relname),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				column->generated = ATTRIBUTE_GENERATED_STORED;
+				column->generated = constraint->generated_kind;
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
 				saw_generated = true;
@@ -988,6 +988,20 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							column->colname, cxt->relation->relname),
 					 parser_errposition(cxt->pstate,
 										constraint->location)));
+
+		/*
+		 * TODO: Straightforward not-null constraints won't work on virtual
+		 * generated columns, because there is no support for expanding the
+		 * column when the constraint is checked.  Maybe we could convert the
+		 * not-null constraint into a full check constraint, so that the
+		 * generation expression can be expanded at check time.
+		 */
+		if (column->is_not_null && column->generated == ATTRIBUTE_GENERATED_VIRTUAL)
+			ereport(ERROR,
+					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					 errmsg("not-null constraints are not supported on virtual generated columns"),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 0227fcbca3d..341e659d6ab 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -27,6 +27,7 @@
 #include "replication/logicalproto.h"
 #include "replication/origin.h"
 #include "replication/pgoutput.h"
+#include "rewrite/rewriteHandler.h"
 #include "utils/builtins.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
@@ -1009,7 +1010,7 @@ pgoutput_row_filter_init(PGOutputData *data, List *publications,
 				continue;
 
 			foreach(lc, rfnodes[idx])
-				filters = lappend(filters, stringToNode((char *) lfirst(lc)));
+				filters = lappend(filters, expand_generated_columns_in_expr(stringToNode((char *) lfirst(lc)), relation, 1));
 
 			/* combine the row filter and cache the ExprState */
 			rfnode = make_orclause(filters);
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 847edcfa90e..e996bdc0d21 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,6 +96,8 @@ static List *matchLocks(CmdType event, Relation relation,
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
+static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+											   RangeTblEntry *rte, int result_relation);
 
 
 /*
@@ -986,7 +988,8 @@ rewriteTargetListIU(List *targetList,
 		if (att_tup->attgenerated)
 		{
 			/*
-			 * stored generated column will be fixed in executor
+			 * virtual generated column stores a null value; stored generated
+			 * column will be fixed in executor
 			 */
 			new_tle = NULL;
 		}
@@ -2187,6 +2190,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
+	 *
+	 * Finally, we expand any virtual generated columns.  We do this after
+	 * each table's RLS policies are applied because the RLS policies might
+	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2200,10 +2207,11 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/* Only normal relations can have RLS policies */
-		if (rte->rtekind != RTE_RELATION ||
-			(rte->relkind != RELKIND_RELATION &&
-			 rte->relkind != RELKIND_PARTITIONED_TABLE))
+		/*
+		 * Only normal relations can have RLS policies or virtual generated
+		 * columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2292,6 +2300,16 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
+		/*
+		 * Expand any references to virtual generated columns of this table.
+		 * Note that subqueries in virtual generated column expressions are
+		 * not currently supported, so this cannot add any more sublinks.
+		 */
+		parsetree = (Query *)
+			expand_generated_columns_internal((Node *) parsetree,
+											  rel, rt_index, rte,
+											  parsetree->resultRelation);
+
 		table_close(rel, NoLock);
 	}
 
@@ -4406,6 +4424,111 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
 }
 
 
+/*
+ * Expand virtual generated columns
+ *
+ * If the table contains virtual generated columns, build a target list
+ * containing the expanded expressions and use ReplaceVarsFromTargetList() to
+ * do the replacements.
+ *
+ * Vars matching rt_index at the current query level are replaced by the
+ * virtual generated column expressions from rel, if there are any.
+ *
+ * The caller must also provide rte, the RTE describing the target relation,
+ * in order to handle any whole-row Vars referencing the target, and
+ * result_relation, the index of the result relation, if this is part of an
+ * INSERT/UPDATE/DELETE/MERGE query.
+ */
+static Node *
+expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
+								  RangeTblEntry *rte, int result_relation)
+{
+	TupleDesc	tupdesc;
+
+	tupdesc = RelationGetDescr(rel);
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		List	   *tlist = NIL;
+
+		for (int i = 0; i < tupdesc->natts; i++)
+		{
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+
+			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				Node	   *defexpr;
+				int			attnum = i + 1;
+				Oid			attcollid;
+				TargetEntry *te;
+
+				defexpr = build_column_default(rel, attnum);
+				if (defexpr == NULL)
+					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+						 attnum, RelationGetRelationName(rel));
+
+				/*
+				 * If the column definition has a collation and it is
+				 * different from the collation of the generation expression,
+				 * put a COLLATE clause around the expression.
+				 */
+				attcollid = attr->attcollation;
+				if (attcollid && attcollid != exprCollation(defexpr))
+				{
+					CollateExpr *ce = makeNode(CollateExpr);
+
+					ce->arg = (Expr *) defexpr;
+					ce->collOid = attcollid;
+					ce->location = -1;
+
+					defexpr = (Node *) ce;
+				}
+
+				ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				tlist = lappend(tlist, te);
+			}
+		}
+
+		Assert(list_length(tlist) > 0);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist,
+										 result_relation,
+										 REPLACEVARS_CHANGE_VARNO, rt_index,
+										 NULL);
+	}
+
+	return node;
+}
+
+/*
+ * Expand virtual generated columns in an expression
+ *
+ * This is for expressions that are not part of a query, such as default
+ * expressions or index predicates.  The rt_index is usually 1.
+ */
+Node *
+expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
+{
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+
+	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+	{
+		RangeTblEntry *rte;
+
+		rte = makeNode(RangeTblEntry);
+		/* eref needs to be set, but the actual name doesn't matter */
+		rte->eref = makeAlias(RelationGetRelationName(rel), NIL);
+		rte->rtekind = RTE_RELATION;
+		rte->relid = RelationGetRelid(rel);
+
+		node = expand_generated_columns_internal(node, rel, rt_index, rte, 0);
+	}
+
+	return node;
+}
+
+
 /*
  * QueryRewrite -
  *	  Primary entry point to the query rewriter.
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 43219a9629c..398114373e9 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -592,6 +592,8 @@ RelationBuildTupleDesc(Relation relation)
 			constr->has_not_null = true;
 		if (attp->attgenerated == ATTRIBUTE_GENERATED_STORED)
 			constr->has_generated_stored = true;
+		if (attp->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+			constr->has_generated_virtual = true;
 		if (attp->atthasdef)
 			ndef++;
 
@@ -674,6 +676,7 @@ RelationBuildTupleDesc(Relation relation)
 	 */
 	if (constr->has_not_null ||
 		constr->has_generated_stored ||
+		constr->has_generated_virtual ||
 		ndef > 0 ||
 		attrmiss ||
 		relation->rd_rel->relchecks > 0)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 02e1fdf8f78..520e1338c28 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -16190,6 +16190,9 @@ dumpTableSchema(Archive *fout, const TableInfo *tbinfo)
 						if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_STORED)
 							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s) STORED",
 											  tbinfo->attrdefs[j]->adef_expr);
+						else if (tbinfo->attgenerated[j] == ATTRIBUTE_GENERATED_VIRTUAL)
+							appendPQExpBuffer(q, " GENERATED ALWAYS AS (%s)",
+											  tbinfo->attrdefs[j]->adef_expr);
 						else
 							appendPQExpBuffer(q, " DEFAULT %s",
 											  tbinfo->attrdefs[j]->adef_expr);
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 805ba9f49fd..bc5d9222a20 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -3706,12 +3706,14 @@
 		create_order => 3,
 		create_sql => 'CREATE TABLE dump_test.test_table_generated (
 						   col1 int primary key,
-						   col2 int generated always as (col1 * 2) stored
+						   col2 int generated always as (col1 * 2) stored,
+						   col3 int generated always as (col1 * 3) virtual
 					   );',
 		regexp => qr/^
 			\QCREATE TABLE dump_test.test_table_generated (\E\n
 			\s+\Qcol1 integer NOT NULL,\E\n
-			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED\E\n
+			\s+\Qcol2 integer GENERATED ALWAYS AS ((col1 * 2)) STORED,\E\n
+			\s+\Qcol3 integer GENERATED ALWAYS AS ((col1 * 3))\E\n
 			\);
 			/xms,
 		like =>
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index aa4363b200a..69d82b44043 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2123,6 +2123,12 @@ describeOneTableDetails(const char *schemaname,
 									   PQgetvalue(res, i, attrdef_col));
 				mustfree = true;
 			}
+			else if (generated[0] == ATTRIBUTE_GENERATED_VIRTUAL)
+			{
+				default_str = psprintf("generated always as (%s)",
+									   PQgetvalue(res, i, attrdef_col));
+				mustfree = true;
+			}
 			else
 				default_str = PQgetvalue(res, i, attrdef_col);
 
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h
index ff27df9e9a6..396eeb7a0bb 100644
--- a/src/include/access/tupdesc.h
+++ b/src/include/access/tupdesc.h
@@ -44,6 +44,7 @@ typedef struct TupleConstr
 	uint16		num_check;
 	bool		has_not_null;
 	bool		has_generated_stored;
+	bool		has_generated_virtual;
 } TupleConstr;
 
 /*
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index cad830dc39c..19c594458bd 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -23,6 +23,7 @@
 #define CHKATYPE_ANYARRAY		0x01	/* allow ANYARRAY */
 #define CHKATYPE_ANYRECORD		0x02	/* allow RECORD and RECORD[] */
 #define CHKATYPE_IS_PARTKEY		0x04	/* attname is part key # not column */
+#define CHKATYPE_IS_VIRTUAL		0x08	/* is virtual generated column */
 
 typedef struct RawColumnDefault
 {
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index b33c315d233..deaa515fe53 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -225,6 +225,7 @@ MAKE_SYSCACHE(ATTNUM, pg_attribute_relid_attnum_index, 128);
 #define		  ATTRIBUTE_IDENTITY_BY_DEFAULT 'd'
 
 #define		  ATTRIBUTE_GENERATED_STORED	's'
+#define		  ATTRIBUTE_GENERATED_VIRTUAL	'v'
 
 #endif							/* EXPOSE_TO_CLIENT_CODE */
 
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index d1ddc39ad37..bf3b592e28f 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -15,9 +15,9 @@
 
 #include "nodes/execnodes.h"
 
-extern void ExecInitStoredGenerated(ResultRelInfo *resultRelInfo,
-									EState *estate,
-									CmdType cmdtype);
+extern void ExecInitGenerated(ResultRelInfo *resultRelInfo,
+							  EState *estate,
+							  CmdType cmdtype);
 
 extern void ExecComputeStoredGenerated(ResultRelInfo *resultRelInfo,
 									   EState *estate, TupleTableSlot *slot,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index aca15f771a2..fe6070381f6 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -556,6 +556,9 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
+	/* true if the above have been computed */
+	bool		ri_Generated_valid;
+
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index ffe155ee20e..8dd421fa0ef 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2812,6 +2812,7 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* CHECK or DEFAULT expression, as
 								 * nodeToString representation */
 	char		generated_when; /* ALWAYS or BY DEFAULT */
+	char		generated_kind; /* STORED or VIRTUAL */
 	bool		nulls_not_distinct; /* null treatment for UNIQUE constraints */
 	List	   *keys;			/* String nodes naming referenced key
 								 * column(s); for UNIQUE/PK/NOT NULL */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index cf2917ad07e..40cf090ce61 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -491,6 +491,7 @@ PG_KEYWORD("verbose", VERBOSE, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("version", VERSION_P, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("view", VIEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("views", VIEWS, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("virtual", VIRTUAL, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("volatile", VOLATILE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("when", WHEN, RESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("where", WHERE, RESERVED_KEYWORD, AS_LABEL)
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index d258b26375f..88fe13c5f4f 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,4 +38,6 @@ extern void error_view_not_updatable(Relation view,
 									 List *mergeActionList,
 									 const char *detail);
 
+extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/pl/plperl/expected/plperl_trigger.out b/src/pl/plperl/expected/plperl_trigger.out
index d4879e2f03b..42c52ecbba8 100644
--- a/src/pl/plperl/expected/plperl_trigger.out
+++ b/src/pl/plperl/expected/plperl_trigger.out
@@ -8,7 +8,8 @@ CREATE TABLE trigger_test (
 );
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
 
@@ -386,7 +387,7 @@ INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 CONTEXT:  PL/Perl function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1b1677e333b..ebf55fe663c 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -3047,6 +3047,9 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generate
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		attname = NameStr(att->attname);
diff --git a/src/pl/plperl/sql/plperl_trigger.sql b/src/pl/plperl/sql/plperl_trigger.sql
index 4adddeb80ac..2798a02fa12 100644
--- a/src/pl/plperl/sql/plperl_trigger.sql
+++ b/src/pl/plperl/sql/plperl_trigger.sql
@@ -10,7 +10,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
     i int,
-    j int GENERATED ALWAYS AS (i * 2) STORED
+    j int GENERATED ALWAYS AS (i * 2) STORED,
+    k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE OR REPLACE FUNCTION trigger_data() RETURNS trigger LANGUAGE plperl AS $$
diff --git a/src/pl/plpython/expected/plpython_trigger.out b/src/pl/plpython/expected/plpython_trigger.out
index 4cb90cb5204..64eab2fa3f4 100644
--- a/src/pl/plpython/expected/plpython_trigger.out
+++ b/src/pl/plpython/expected/plpython_trigger.out
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 	(i int, v text );
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
 
@@ -614,8 +615,8 @@ ERROR:  cannot set generated column "j"
 CONTEXT:  while modifying trigger row
 PL/Python function "generated_test_func1"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
 -- recursive call of a trigger mustn't corrupt TD (bug #18456)
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index db14c5f8dae..51e1d610259 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -844,6 +844,9 @@ PLyDict_FromTuple(PLyDatumToOb *arg, HeapTuple tuple, TupleDesc desc, bool inclu
 				/* don't include unless requested */
 				if (!include_generated)
 					continue;
+				/* never include virtual columns */
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+					continue;
 			}
 
 			key = NameStr(attr->attname);
diff --git a/src/pl/plpython/sql/plpython_trigger.sql b/src/pl/plpython/sql/plpython_trigger.sql
index f6c2ef8d6a0..440549c0785 100644
--- a/src/pl/plpython/sql/plpython_trigger.sql
+++ b/src/pl/plpython/sql/plpython_trigger.sql
@@ -69,7 +69,8 @@ CREATE TABLE trigger_test
 
 CREATE TABLE trigger_test_generated (
 	i int,
-        j int GENERATED ALWAYS AS (i * 2) STORED
+        j int GENERATED ALWAYS AS (i * 2) STORED,
+        k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE FUNCTION trigger_data() RETURNS trigger LANGUAGE plpython3u AS $$
diff --git a/src/pl/tcl/expected/pltcl_trigger.out b/src/pl/tcl/expected/pltcl_trigger.out
index 129abd5ba67..5298e50a5ec 100644
--- a/src/pl/tcl/expected/pltcl_trigger.out
+++ b/src/pl/tcl/expected/pltcl_trigger.out
@@ -63,7 +63,8 @@ CREATE TABLE trigger_test (
 ALTER TABLE trigger_test DROP dropme;
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
 CREATE FUNCTION trigger_data() returns trigger language pltcl as $_$
@@ -647,7 +648,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -658,7 +659,7 @@ NOTICE:  OLD: {}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: INSERT
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -670,7 +671,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -681,7 +682,7 @@ NOTICE:  OLD: {i: 1, j: 2}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: UPDATE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -693,7 +694,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_before
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -704,7 +705,7 @@ NOTICE:  OLD: {i: 11, j: 22}
 NOTICE:  TG_level: ROW
 NOTICE:  TG_name: show_trigger_data_trig_after
 NOTICE:  TG_op: DELETE
-NOTICE:  TG_relatts: {{} i j}
+NOTICE:  TG_relatts: {{} i j k}
 NOTICE:  TG_relid: bogus:12345
 NOTICE:  TG_table_name: trigger_test_generated
 NOTICE:  TG_table_schema: public
@@ -882,7 +883,7 @@ TRUNCATE trigger_test_generated;
 INSERT INTO trigger_test_generated (i) VALUES (1);
 ERROR:  cannot set generated column "j"
 SELECT * FROM trigger_test_generated;
- i | j 
----+---
+ i | j | k 
+---+---+---
 (0 rows)
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index feb6a76b56c..08c8492050e 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -3206,6 +3206,9 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc, bool include_gene
 			/* don't include unless requested */
 			if (!include_generated)
 				continue;
+			/* never include virtual columns */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				continue;
 		}
 
 		/************************************************************
diff --git a/src/pl/tcl/sql/pltcl_trigger.sql b/src/pl/tcl/sql/pltcl_trigger.sql
index 2a244de83bc..0ed00f49526 100644
--- a/src/pl/tcl/sql/pltcl_trigger.sql
+++ b/src/pl/tcl/sql/pltcl_trigger.sql
@@ -73,7 +73,8 @@ CREATE TABLE trigger_test (
 
 CREATE TABLE trigger_test_generated (
    i int,
-   j int GENERATED ALWAYS AS (i * 2) STORED
+   j int GENERATED ALWAYS AS (i * 2) STORED,
+   k int GENERATED ALWAYS AS (i * 3) VIRTUAL
 );
 
 CREATE VIEW trigger_test_view AS SELECT i, v FROM trigger_test;
diff --git a/src/test/regress/expected/collate.icu.utf8.out b/src/test/regress/expected/collate.icu.utf8.out
index 910de9120f2..96a134d1561 100644
--- a/src/test/regress/expected/collate.icu.utf8.out
+++ b/src/test/regress/expected/collate.icu.utf8.out
@@ -2555,6 +2555,26 @@ DROP TABLE pagg_tab6;
 RESET enable_partitionwise_aggregate;
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+ a | b  | c  
+---+----+----
+ 1 | D1 | D1
+ 2 | D2 | D2
+ 3 | d1 | d1
+(3 rows)
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index e0613891351..2cebe382432 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -113,19 +113,20 @@ SELECT * FROM test_like_id_3;  -- identity was copied and applied
 (1 row)
 
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
                         Table "public.test_like_gen_1"
  Column |  Type   | Collation | Nullable |              Default               
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
@@ -135,12 +136,13 @@ CREATE TABLE test_like_gen_2 (LIKE test_like_gen_1);
 --------+---------+-----------+----------+---------
  a      | integer |           |          | 
  b      | integer |           |          | 
+ c      | integer |           |          | 
 
 INSERT INTO test_like_gen_2 (a) VALUES (1);
 SELECT * FROM test_like_gen_2;
- a | b 
----+---
- 1 |  
+ a | b | c 
+---+---+---
+ 1 |   |  
 (1 row)
 
 CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
@@ -150,12 +152,13 @@ CREATE TABLE test_like_gen_3 (LIKE test_like_gen_1 INCLUDING GENERATED);
 --------+---------+-----------+----------+------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | generated always as (a * 2) stored
+ c      | integer |           |          | generated always as (a * 3)
 
 INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
- a | b 
----+---
- 1 | 2
+ a | b | c 
+---+---+---
+ 1 | 2 | 3
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
diff --git a/src/test/regress/expected/fast_default.out b/src/test/regress/expected/fast_default.out
index 59365dad964..272b57e48cd 100644
--- a/src/test/regress/expected/fast_default.out
+++ b/src/test/regress/expected/fast_default.out
@@ -58,6 +58,18 @@ ALTER TABLE has_volatile ADD col2 int DEFAULT 1;
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 NOTICE:  rewriting table has_volatile for reason 2
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+NOTICE:  rewriting table has_volatile for reason 4
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+NOTICE:  rewriting table has_volatile for reason 2
 -- Test a large sample of different datatypes
 CREATE TABLE T(pk INT NOT NULL PRIMARY KEY, c_int INT DEFAULT 1);
 SELECT set('t');
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_stored.out
index 7653326420e..3ce0dd1831c 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_stored.out
@@ -1,3 +1,4 @@
+-- keep these tests aligned with generated_virtual.sql
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -357,6 +358,10 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
@@ -868,6 +873,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -881,6 +891,11 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
 ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is STORED, child column is VIRTUAL.
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -1188,9 +1203,9 @@ SELECT * FROM gtest29;
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1471,7 +1486,7 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
  x      | integer |           |          | generated always as (b * 2) stored
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
diff --git a/src/test/regress/expected/generated_stored.out b/src/test/regress/expected/generated_virtual.out
similarity index 72%
copy from src/test/regress/expected/generated_stored.out
copy to src/test/regress/expected/generated_virtual.out
index 7653326420e..35638812be9 100644
--- a/src/test/regress/expected/generated_stored.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1,9 +1,10 @@
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+-- keep these tests aligned with generated_stored.sql
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
  table_name | column_name | column_default | is_nullable | is_generated | generation_expression 
 ------------+-------------+----------------+-------------+--------------+-----------------------
  gtest0     | a           |                | NO          | NEVER        | 
@@ -12,89 +13,89 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
  gtest1     | b           |                | YES         | ALWAYS       | (a * 2)
 (4 rows)
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
  table_name | column_name | dependent_column 
 ------------+-------------+------------------
  gtest1     | a           | b
 (1 row)
 
 \d gtest1
-                    Table "generated_stored_tests.gtest1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Indexes:
     "gtest1_pkey" PRIMARY KEY, btree (a)
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 ERROR:  multiple generation clauses specified for column "b" of table "gtest_err_1"
-LINE 1: ...ARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ...
+LINE 1: ...RY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ...
                                                              ^
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STO...
+LINE 1: ...2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 ERROR:  cannot use generated column "b" in column generation expression
-LINE 1: ...AYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STO...
+LINE 1: ...YS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIR...
                                                              ^
 DETAIL:  A generated column cannot reference another generated column.
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 ERROR:  cannot use whole-row variable in column generation expression
-LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STOR...
+LINE 2:     b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRT...
                                                  ^
 DETAIL:  This would cause the generated column to depend on its own value.
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 ERROR:  column "c" does not exist
-LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STO...
+LINE 1: ..._3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIR...
                                                              ^
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 ERROR:  generation expression is not immutable
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both default and generation expression specified for column "b" of table "gtest_err_5a"
 LINE 1: ... gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ...
                                                              ^
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ERROR:  both identity and generation expression specified for column "b" of table "gtest_err_5b"
 LINE 1: ...t PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ...
                                                              ^
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 ERROR:  cannot use system column "xmin" in column generation expression
 LINE 1: ...a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37...
                                                              ^
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
 ERROR:  aggregate functions are not allowed in column generation expressions
-LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) ST...
+LINE 1: ...7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VI...
                                                              ^
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
 ERROR:  window functions are not allowed in column generation expressions
 LINE 1: ...7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number...
                                                              ^
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
 ERROR:  cannot use subquery in column generation expression
 LINE 1: ...7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)...
                                                              ^
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 ERROR:  set-returning functions are not allowed in column generation expressions
 LINE 1: ...7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_s...
                                                              ^
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 ERROR:  for a generated column, GENERATED ALWAYS must be specified
 LINE 1: ...E gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT...
                                                              ^
@@ -165,16 +166,10 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
-ERROR:  integer out of range
 SELECT * FROM gtest1;
- a | b 
----+---
- 2 | 4
- 1 | 2
-(2 rows)
-
+ERROR:  integer out of range
 DELETE FROM gtest1 WHERE a = 2000000000;
 -- test with joins
 CREATE TABLE gtestx (x int, y int);
@@ -220,8 +215,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -244,7 +239,7 @@ SELECT * FROM gtestm ORDER BY id;
 DROP TABLE gtestm;
 CREATE TABLE gtestm (
   a int PRIMARY KEY,
-  b int GENERATED ALWAYS AS (a * 2) STORED
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
 MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
@@ -318,11 +313,11 @@ SELECT * FROM gtest1_1;
 (0 rows)
 
 \d gtest1_1
-                   Table "generated_stored_tests.gtest1_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest1
 
 INSERT INTO gtest1_1 VALUES (4);
@@ -341,12 +336,12 @@ SELECT * FROM gtest1;
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging column "b" with inherited definition
 ERROR:  child column "b" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 ERROR:  column "b" in child table must not be a generated column
 DROP TABLE gtest_normal, gtest_normal_child;
@@ -357,26 +352,30 @@ ERROR:  column "b" inherits from generated column but specifies default
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
 NOTICE:  merging column "b" with inherited definition
 ERROR:  column "b" inherits from generated column but specifies identity
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+NOTICE:  merging column "b" with inherited definition
+ERROR:  column "b" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 NOTICE:  merging column "b" with inherited definition
 \d+ gtestx
-                                        Table "generated_stored_tests.gtestx"
- Column |  Type   | Collation | Nullable |               Default               | Storage | Stats target | Description 
---------+---------+-----------+----------+-------------------------------------+---------+--------------+-------------
- a      | integer |           | not null |                                     | plain   |              | 
- b      | integer |           |          | generated always as (a * 22) stored | plain   |              | 
- x      | integer |           |          |                                     | plain   |              | 
+                                    Table "generated_virtual_tests.gtestx"
+ Column |  Type   | Collation | Nullable |           Default            | Storage | Stats target | Description 
+--------+---------+-----------+----------+------------------------------+---------+--------------+-------------
+ a      | integer |           | not null |                              | plain   |              | 
+ b      | integer |           |          | generated always as (a * 22) | plain   |              | 
+ x      | integer |           |          |                              | plain   |              | 
 Not-null constraints:
     "gtest1_a_not_null" NOT NULL "a" (inherited)
 Inherits: gtest1
 
 INSERT INTO gtestx (a, x) VALUES (11, 22);
 SELECT * FROM gtest1;
- a  |  b  
-----+-----
-  3 |   6
-  4 |   8
- 11 | 242
+ a  | b  
+----+----
+  3 |  6
+  4 |  8
+ 11 | 22
 (3 rows)
 
 SELECT * FROM gtestx;
@@ -388,9 +387,9 @@ SELECT * FROM gtestx;
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
 ERROR:  column "b" in child table must be a generated column
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 -- test multiple inheritance mismatches
 CREATE TABLE gtesty (x int, b int DEFAULT 55);
@@ -403,28 +402,28 @@ CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  inherited column "b" has a generation conflict
 DROP TABLE gtesty;
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 NOTICE:  merging multiple inherited definitions of column "b"
 ERROR:  column "b" inherits conflicting generation expressions
 HINT:  To resolve the conflict, specify a generation expression explicitly.
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 NOTICE:  merging multiple inherited definitions of column "b"
 NOTICE:  moving and merging column "b" with inherited definition
 DETAIL:  User-specified column moved to the position of the inherited column.
 \d gtest1_y
-                   Table "generated_stored_tests.gtest1_y"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest1_y"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           | not null | 
- b      | integer |           |          | generated always as (x + 1) stored
+ b      | integer |           |          | generated always as (x + 1)
  x      | integer |           |          | 
 Inherits: gtest1,
           gtesty
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
  f1 | f2 
@@ -441,8 +440,8 @@ TABLE gtestc;
 
 DROP TABLE gtestp CASCADE;
 NOTICE:  drop cascades to table gtestc
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
  a | b 
@@ -463,7 +462,7 @@ SELECT * FROM gtest3 ORDER BY a;
     |   
 (4 rows)
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
  a |  b  
@@ -528,7 +527,7 @@ SELECT * FROM gtest3 ORDER BY a;
 (4 rows)
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
  a | b 
@@ -537,7 +536,7 @@ SELECT * FROM gtest2;
 (1 row)
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -552,7 +551,7 @@ DROP TABLE gtest_varlena;
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -567,11 +566,11 @@ DROP TYPE double_int;
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
  a | b |       c        
 ---+---+----------------
@@ -580,7 +579,7 @@ SELECT * FROM gtest_tableoid;
 (2 rows)
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ERROR:  cannot drop column b of table gtest10 because other objects depend on it
 DETAIL:  column c of table gtest10 depends on column b of table gtest10
@@ -588,24 +587,24 @@ HINT:  Use DROP ... CASCADE to drop the dependent objects too.
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 NOTICE:  drop cascades to column c of table gtest10
 \d gtest10
-      Table "generated_stored_tests.gtest10"
+      Table "generated_virtual_tests.gtest10"
  Column |  Type   | Collation | Nullable | Default 
 --------+---------+-----------+----------+---------
  a      | integer |           | not null | 
 Indexes:
     "gtest10_pkey" PRIMARY KEY, btree (a)
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 -- privileges
 CREATE USER regress_user11;
-CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 INSERT INTO gtest11 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest11 TO regress_user11;
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
-CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
+CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
 INSERT INTO gtest12 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c), INSERT ON gtest12 TO regress_user11;
 SET ROLE regress_user11;
@@ -620,15 +619,9 @@ SELECT a, c FROM gtest11;  -- allowed
 
 SELECT gf1(10);  -- not allowed
 ERROR:  permission denied for function gf1
-INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
+INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12;  -- currently not allowed because of function permissions, should arguably be allowed
 ERROR:  permission denied for function gf1
-SELECT a, c FROM gtest12;  -- allowed (does not actually invoke the function)
- a | c  
----+----
- 1 | 30
- 2 | 60
-(2 rows)
-
 RESET ROLE;
 DROP FUNCTION gf1(int);  -- fail
 ERROR:  cannot drop function gf1(integer) because other objects depend on it
@@ -638,227 +631,147 @@ DROP TABLE gtest11, gtest12;
 DROP FUNCTION gf1(int);
 DROP USER regress_user11;
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 ERROR:  new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL:  Failing row contains (30, 60).
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ERROR:  check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+DETAIL:  Failing row contains (30, virtual).
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables with check constraints
+DETAIL:  Column "b" of relation "gtest20" is a virtual generated column.
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 ERROR:  check constraint "gtest20a_b_check" of relation "gtest20a" is violated by some row
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 ERROR:  check constraint "chk" of relation "gtest20b" is violated by some row
 -- check with whole-row reference
-CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
 INSERT INTO gtest20c VALUES (1);  -- ok
 INSERT INTO gtest20c VALUES (NULL);  -- fails
 ERROR:  new row for relation "gtest20c" violates check constraint "whole_row_check"
-DETAIL:  Failing row contains (null, null).
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+DETAIL:  Failing row contains (null, virtual).
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+ERROR:  not-null constraints are not supported on virtual generated columns
+LINE 1: ... b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+                                                             ^
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+ERROR:  not-null constraints are not supported on virtual generated columns
+DROP TABLE gtest21ax;
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
-ERROR:  null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL:  Failing row contains (0, null).
+ERROR:  not-null constraints are not supported on virtual generated columns
+DETAIL:  Column "b" of relation "gtest21b" is a virtual generated column.
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-ERROR:  duplicate key value violates unique constraint "gtest22a_b_key"
-DETAIL:  Key (b)=(1) already exists.
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
-ERROR:  duplicate key value violates unique constraint "gtest22b_pkey"
-DETAIL:  Key (a, b)=(2, 1) already exists.
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+ERROR:  unique constraints on virtual generated columns are not supported
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-                   Table "generated_stored_tests.gtest22c"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest22c_b_idx" btree (b)
-    "gtest22c_expr_idx" btree ((b * 3))
-    "gtest22c_pred_idx" btree (a) WHERE b > 0
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 4)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 4;
- a | b 
----+---
- 2 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 6)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 6;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 2
-(1 row)
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-                 QUERY PLAN                  
----------------------------------------------
- Index Scan using gtest22c_b_idx on gtest22c
-   Index Cond: (b = 8)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b = 8;
- a | b 
----+---
- 2 | 8
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_expr_idx on gtest22c
-   Index Cond: ((b * 3) = 12)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE b * 3 = 12;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-                   QUERY PLAN                   
-------------------------------------------------
- Index Scan using gtest22c_pred_idx on gtest22c
-   Index Cond: (a = 1)
-(2 rows)
-
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
- a | b 
----+---
- 1 | 4
-(1 row)
-
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
 ERROR:  invalid ON UPDATE action for foreign key constraint containing generated column
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 ERROR:  invalid ON DELETE action for foreign key constraint containing generated column
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
-                   Table "generated_stored_tests.gtest23b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
- a      | integer |           | not null | 
- b      | integer |           |          | generated always as (a * 2) stored
-Indexes:
-    "gtest23b_pkey" PRIMARY KEY, btree (a)
-Foreign-key constraints:
-    "gtest23b_b_fkey" FOREIGN KEY (b) REFERENCES gtest23a(x)
-
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(10) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ERROR:  insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23a".
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+ERROR:  foreign key constraints on virtual generated columns are not supported
+--\d gtest23b
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+ERROR:  not-null constraints are not supported on virtual generated columns
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
-ERROR:  insert or update on table "gtest23q" violates foreign key constraint "gtest23q_b_fkey"
-DETAIL:  Key (b)=(5) is not present in table "gtest23p".
+ERROR:  relation "gtest23p" does not exist
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
-CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
-INSERT INTO gtest24r (a) VALUES (4);  -- ok
-INSERT INTO gtest24r (a) VALUES (6);  -- error
-ERROR:  value for domain gtestdomain1 violates check constraint "gtestdomain1_check"
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+ERROR:  virtual generated column "b" cannot have a domain type
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 ERROR:  generated columns are not supported on typed tables
 DROP TYPE gtest_type CASCADE;
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  child column "f3" specifies generation expression
 HINT:  A child table column cannot be generated unless its parent column is.
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 ERROR:  column "f3" in child table must not be a generated column
 DROP TABLE gtest_parent, gtest_child;
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -868,6 +781,11 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 ERROR:  identity columns are not supported on partitions
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 ERROR:  column "f3" in child table must be a generated column
@@ -882,32 +800,37 @@ ERROR:  table "gtest_child3" being attached contains an identity column "f3"
 DETAIL:  The new partition may not contain an identity column.
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+ERROR:  column "f3" inherits from generated column of different kind
+DETAIL:  Parent column is VIRTUAL, child column is STORED.
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
@@ -918,7 +841,7 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  1 |  2
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
+ gtest_child2 | 08-15-2016 |  3 |  6
 (3 rows)
 
 SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
@@ -928,7 +851,7 @@ SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
  gtest_child | 07-15-2016 |  2 |  4
 (2 rows)
 
-SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child2 | 08-15-2016 |  3 | 66
@@ -944,95 +867,95 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
  gtest_child  | 07-15-2016 |  2 |  4
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child2 | 08-15-2016 |  3 |  6
+ gtest_child3 | 09-13-2016 |  1 |  2
 (3 rows)
 
 -- alter only parent's and one child's generation expression
 ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
 ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 4) stored
+ f3     | bigint |           |          | generated always as (f2 * 4)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 10) stored
+ f3     | bigint |           |          | generated always as (f2 * 10)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                  Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 22) stored
+ f3     | bigint |           |          | generated always as (f2 * 22)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                  Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default                
---------+--------+-----------+----------+--------------------------------------
+              Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |            Default            
+--------+--------+-----------+----------+-------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 33) stored
+ f3     | bigint |           |          | generated always as (f2 * 33)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
    tableoid   |     f1     | f2 | f3 
 --------------+------------+----+----
- gtest_child  | 07-15-2016 |  2 | 20
- gtest_child2 | 08-15-2016 |  3 | 66
- gtest_child3 | 09-13-2016 |  1 | 33
+ gtest_child  | 07-15-2016 |  2 |  8
+ gtest_child2 | 08-15-2016 |  3 | 12
+ gtest_child3 | 09-13-2016 |  1 |  4
 (3 rows)
 
 -- alter generation expression of parent and all its children altogether
 ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
 \d gtest_parent
-           Partitioned table "generated_stored_tests.gtest_parent"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+       Partitioned table "generated_virtual_tests.gtest_parent"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition key: RANGE (f1)
 Number of partitions: 3 (Use \d+ to list them.)
 
 \d gtest_child
-                  Table "generated_stored_tests.gtest_child"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+              Table "generated_virtual_tests.gtest_child"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
 
 \d gtest_child2
-                 Table "generated_stored_tests.gtest_child2"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child2"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
 
 \d gtest_child3
-                 Table "generated_stored_tests.gtest_child3"
- Column |  Type  | Collation | Nullable |               Default               
---------+--------+-----------+----------+-------------------------------------
+             Table "generated_virtual_tests.gtest_child3"
+ Column |  Type  | Collation | Nullable |           Default            
+--------+--------+-----------+----------+------------------------------
  f1     | date   |           | not null | 
  f2     | bigint |           |          | 
- f3     | bigint |           |          | generated always as (f2 * 2) stored
+ f3     | bigint |           |          | generated always as (f2 * 2)
 Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
 
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -1045,20 +968,20 @@ SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
+LINE 1: ...NERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
                                                                    ^
 DETAIL:  Column "f3" is a generated column.
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 ERROR:  cannot use generated column in partition key
-LINE 1: ...ED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+LINE 1: ...D ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
                                                              ^
 DETAIL:  Column "f3" is a generated column.
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
  a | b  
 ---+----
@@ -1066,16 +989,16 @@ SELECT * FROM gtest25 ORDER BY a;
  4 | 12
 (2 rows)
 
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
 ERROR:  cannot use generated column "b" in column generation expression
 DETAIL:  A generated column cannot reference another generated column.
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ERROR:  column "z" does not exist
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
  a | b  | c  |  x  |  d  |  y  
 ---+----+----+-----+-----+-----
@@ -1084,15 +1007,15 @@ SELECT * FROM gtest25 ORDER BY a;
 (2 rows)
 
 \d gtest25
-                                 Table "generated_stored_tests.gtest25"
- Column |       Type       | Collation | Nullable |                       Default                        
---------+------------------+-----------+----------+------------------------------------------------------
+                             Table "generated_virtual_tests.gtest25"
+ Column |       Type       | Collation | Nullable |                    Default                    
+--------+------------------+-----------+----------+-----------------------------------------------
  a      | integer          |           | not null | 
- b      | integer          |           |          | generated always as (a * 3) stored
+ b      | integer          |           |          | generated always as (a * 3)
  c      | integer          |           |          | 42
- x      | integer          |           |          | generated always as (c * 4) stored
+ x      | integer          |           |          | generated always as (c * 4)
  d      | double precision |           |          | 101
- y      | double precision |           |          | generated always as (d * 4::double precision) stored
+ y      | double precision |           |          | generated always as (d * 4::double precision)
 Indexes:
     "gtest25_pkey" PRIMARY KEY, btree (a)
 
@@ -1100,7 +1023,7 @@ Indexes:
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -1108,12 +1031,12 @@ ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 ALTER TABLE gtest27 ALTER COLUMN x TYPE numeric;
 \d gtest27
-                        Table "generated_stored_tests.gtest27"
- Column |  Type   | Collation | Nullable |                  Default                   
---------+---------+-----------+----------+--------------------------------------------
+                    Table "generated_virtual_tests.gtest27"
+ Column |  Type   | Collation | Nullable |               Default               
+--------+---------+-----------+----------+-------------------------------------
  a      | integer |           |          | 
  b      | integer |           |          | 
- x      | numeric |           |          | generated always as (((a + b) * 2)) stored
+ x      | numeric |           |          | generated always as (((a + b) * 2))
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1129,20 +1052,19 @@ LINE 1: ALTER TABLE gtest27 ALTER COLUMN x TYPE boolean USING x <> 0...
 DETAIL:  Column "x" is a generated column.
 ALTER TABLE gtest27 ALTER COLUMN x DROP DEFAULT;  -- error
 ERROR:  column "x" of relation "gtest27" is a generated column
-HINT:  Use ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION instead.
 -- It's possible to alter the column types this way:
 ALTER TABLE gtest27
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -1151,12 +1073,12 @@ ALTER TABLE gtest27
 ERROR:  cannot alter type of a column used by a generated column
 DETAIL:  Column "a" is used by generated column "x".
 \d gtest27
-                      Table "generated_stored_tests.gtest27"
- Column |  Type  | Collation | Nullable |                 Default                  
---------+--------+-----------+----------+------------------------------------------
+                  Table "generated_virtual_tests.gtest27"
+ Column |  Type  | Collation | Nullable |              Default              
+--------+--------+-----------+----------+-----------------------------------
  a      | bigint |           |          | 
  b      | bigint |           |          | 
- x      | bigint |           |          | generated always as ((a + b) * 2) stored
+ x      | bigint |           |          | generated always as ((a + b) * 2)
 
 SELECT * FROM gtest27;
  a | b  | x  
@@ -1168,7 +1090,7 @@ SELECT * FROM gtest27;
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -1179,18 +1101,18 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 
 ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3);  -- error
 ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION;  -- error
-ERROR:  column "a" of relation "gtest29" is not a stored generated column
+ERROR:  column "a" of relation "gtest29" is not a generated column
 ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS;  -- notice
-NOTICE:  column "a" of relation "gtest29" is not a stored generated column, skipping
+NOTICE:  column "a" of relation "gtest29" is not a generated column, skipping
 -- Change the expression
 ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest29;
@@ -1201,97 +1123,97 @@ SELECT * FROM gtest29;
 (2 rows)
 
 \d gtest29
-                    Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 3) stored
+ b      | integer |           |          | generated always as (a * 3)
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest29" is a virtual generated column.
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
+ERROR:  cannot insert a non-DEFAULT value into column "b"
+DETAIL:  Column "b" is a generated column.
 SELECT * FROM gtest29;
  a | b  
 ---+----
  3 |  9
  4 | 12
- 5 |   
- 6 | 66
-(4 rows)
+ 5 | 15
+(3 rows)
 
 \d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest29"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 3)
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
-      Table "generated_stored_tests.gtest29"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
- b      | integer |           |          | 
-
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
+ERROR:  ALTER TABLE / DROP EXPRESSION is not supported for virtual generated columns
+DETAIL:  Column "b" of relation "gtest30" is a virtual generated column.
 \d gtest30
-      Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-     Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable | Default 
---------+---------+-----------+----------+---------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | 
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 DROP TABLE gtest30 CASCADE;
 NOTICE:  drop cascades to table gtest30_1
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  ALTER TABLE / DROP EXPRESSION must be applied to child tables too
 \d gtest30
-                    Table "generated_stored_tests.gtest30"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+                Table "generated_virtual_tests.gtest30"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Number of child tables: 1 (Use \d+ to list them.)
 
 \d gtest30_1
-                   Table "generated_stored_tests.gtest30_1"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest30_1"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  a      | integer |           |          | 
- b      | integer |           |          | generated always as (a * 2) stored
+ b      | integer |           |          | generated always as (a * 2)
 Inherits: gtest30
 
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 ERROR:  cannot drop generation expression from inherited column
 -- composite type dependencies
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
 DROP TABLE gtest31_1, gtest31_2;
 -- Check it for a partitioned table, too
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 ERROR:  cannot alter table "gtest31_1" because column "gtest31_2.y" uses its row type
@@ -1299,7 +1221,7 @@ DROP TABLE gtest31_1, gtest31_2;
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
   LANGUAGE plpgsql
@@ -1352,7 +1274,7 @@ CREATE TRIGGER gtest4 AFTER INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (-2), (0), (3);
 INFO:  gtest2: BEFORE: new = (-2,)
-INFO:  gtest4: AFTER: new = (-2,-4)
+INFO:  gtest4: AFTER: new = (-2,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1362,12 +1284,12 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 UPDATE gtest26 SET a = a * -2;
-INFO:  gtest1: BEFORE: old = (-2,-4)
+INFO:  gtest1: BEFORE: old = (-2,)
 INFO:  gtest1: BEFORE: new = (4,)
-INFO:  gtest3: AFTER: old = (-2,-4)
-INFO:  gtest3: AFTER: new = (4,8)
-INFO:  gtest4: AFTER: old = (3,6)
-INFO:  gtest4: AFTER: new = (-6,-12)
+INFO:  gtest3: AFTER: old = (-2,)
+INFO:  gtest3: AFTER: new = (4,)
+INFO:  gtest4: AFTER: old = (3,)
+INFO:  gtest4: AFTER: new = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a  |  b  
 ----+-----
@@ -1377,8 +1299,8 @@ SELECT * FROM gtest26 ORDER BY a;
 (3 rows)
 
 DELETE FROM gtest26 WHERE a = -6;
-INFO:  gtest1: BEFORE: old = (-6,-12)
-INFO:  gtest3: AFTER: old = (-6,-12)
+INFO:  gtest1: BEFORE: old = (-6,)
+INFO:  gtest3: AFTER: old = (-6,)
 SELECT * FROM gtest26 ORDER BY a;
  a | b 
 ---+---
@@ -1428,7 +1350,7 @@ CREATE TRIGGER gtest12_03 BEFORE INSERT OR UPDATE ON gtest26
   EXECUTE PROCEDURE gtest_trigger_func();
 INSERT INTO gtest26 (a) VALUES (1);
 INFO:  gtest12_01: BEFORE: new = (1,)
-INFO:  gtest12_03: BEFORE: new = (10,300)
+INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
 ----+----
@@ -1436,9 +1358,9 @@ SELECT * FROM gtest26 ORDER BY a;
 (1 row)
 
 UPDATE gtest26 SET a = 11 WHERE a = 10;
-INFO:  gtest12_01: BEFORE: old = (10,20)
+INFO:  gtest12_01: BEFORE: old = (10,)
 INFO:  gtest12_01: BEFORE: new = (11,)
-INFO:  gtest12_03: BEFORE: old = (10,20)
+INFO:  gtest12_03: BEFORE: old = (10,)
 INFO:  gtest12_03: BEFORE: new = (10,)
 SELECT * FROM gtest26 ORDER BY a;
  a  | b  
@@ -1451,27 +1373,27 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 ALTER TABLE gtest28a DROP COLUMN a;
 CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 \d gtest28*
-                   Table "generated_stored_tests.gtest28a"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28a"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
-                   Table "generated_stored_tests.gtest28b"
- Column |  Type   | Collation | Nullable |              Default               
---------+---------+-----------+----------+------------------------------------
+               Table "generated_virtual_tests.gtest28b"
+ Column |  Type   | Collation | Nullable |           Default           
+--------+---------+-----------+----------+-----------------------------
  b      | integer |           |          | 
  c      | integer |           |          | 
- x      | integer |           |          | generated always as (b * 2) stored
+ x      | integer |           |          | generated always as (b * 2)
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
  attrelid | attname | attgenerated 
 ----------+---------+--------------
 (0 rows)
diff --git a/src/test/regress/expected/publication.out b/src/test/regress/expected/publication.out
index bc3898fbe58..99e98bcbdce 100644
--- a/src/test/regress/expected/publication.out
+++ b/src/test/regress/expected/publication.out
@@ -442,7 +442,7 @@ LINE 1: ...ICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
                                                              ^
 DETAIL:  User-defined operators are not allowed.
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 ERROR:  invalid publication WHERE expression
 LINE 1: ...ON testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf...
@@ -523,17 +523,33 @@ Tables:
 Tables from schemas:
     "testpub_rf_schema2"
 
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+ERROR:  invalid publication WHERE expression
+DETAIL:  User-defined or built-in mutable functions are not allowed.
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+ERROR:  ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns on tables that are part of a publication
+DETAIL:  Column "y" of relation "testpub_rf_tbl7" is a virtual generated column.
+RESET client_min_messages;
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
@@ -711,7 +727,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 ERROR:  column "x" of relation "testpub_tbl5" does not exist
@@ -748,9 +766,12 @@ UPDATE testpub_tbl5 SET a = 1;
 ERROR:  cannot update table "testpub_tbl5"
 DETAIL:  Column list used by the publication does not cover the replica identity.
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
+ERROR:  cannot use virtual generated column "e" in publication column list
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
 ALTER TABLE testpub_tbl5 REPLICA IDENTITY USING INDEX testpub_tbl5_b_key;
diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index fd5654df35e..87929191d06 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -4379,6 +4379,35 @@ ERROR:  new row violates row-level security policy for table "r1"
 INSERT INTO r1 VALUES (10)
     ON CONFLICT ON CONSTRAINT r1_pkey DO UPDATE SET a = 30;
 ERROR:  new row violates row-level security policy for table "r1"
+DROP TABLE r1;
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+ERROR:  new row violates row-level security policy "p1" for table "r1"
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+ERROR:  new row violates row-level security policy "p2" for table "r1"
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+ a | b  |  c  
+---+----+-----
+ 2 | 20 | 200
+ 3 | 30 | 300
+(2 rows)
+
 DROP TABLE r1;
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out
index a4c7be487ef..9a820404d3f 100644
--- a/src/test/regress/expected/stats_ext.out
+++ b/src/test/regress/expected/stats_ext.out
@@ -66,6 +66,29 @@ ERROR:  syntax error at or near ","
 LINE 1: CREATE STATISTICS tst ON (x, y) FROM ext_stats_test;
                                    ^
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+ERROR:  statistics creation on virtual generated columns is not supported
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+ERROR:  statistics creation on system columns is not supported
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+ERROR:  column "w" cannot be used in statistics because its type xid has no default btree operator class
+DROP TABLE ext_stats_test1;
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
 CREATE STATISTICS IF NOT EXISTS ab1_a_b_stats ON a, b FROM ab1;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 1edd9e45ebb..e63ee2cf2bb 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -78,7 +78,7 @@ test: brin_bloom brin_multi
 # psql depends on create_am
 # amutils depends on geometry, create_index_spgist, hash_index, brin
 # ----------
-test: create_table_like alter_generic alter_operator misc async dbsize merge misc_functions sysviews tsrf tid tidscan tidrangescan collate.utf8 collate.icu.utf8 incremental_sort create_role without_overlaps
+test: create_table_like alter_generic alter_operator misc async dbsize merge misc_functions sysviews tsrf tid tidscan tidrangescan collate.utf8 collate.icu.utf8 incremental_sort create_role without_overlaps generated_virtual
 
 # collate.linux.utf8 and collate.icu.utf8 tests cannot be run in parallel with each other
 test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8 collate.windows.win1252
diff --git a/src/test/regress/sql/collate.icu.utf8.sql b/src/test/regress/sql/collate.icu.utf8.sql
index f99f186f2d6..eea50e34c2d 100644
--- a/src/test/regress/sql/collate.icu.utf8.sql
+++ b/src/test/regress/sql/collate.icu.utf8.sql
@@ -955,6 +955,21 @@ CREATE TABLE pagg_tab6_p2 PARTITION OF pagg_tab6 FOR VALUES IN ('c', 'd');
 RESET max_parallel_workers_per_gather;
 RESET enable_incremental_sort;
 
+-- virtual generated columns
+CREATE TABLE t5 (
+    a int,
+    b text collate "C",
+    c text collate "C" GENERATED ALWAYS AS (b COLLATE case_insensitive)
+);
+INSERT INTO t5 (a, b) values (1, 'D1'), (2, 'D2'), (3, 'd1');
+-- Collation of c should be the one defined for the column ("C"), not
+-- the one of the generation expression.  (Note that we cannot just
+-- test with, say, using COLLATION FOR, because the collation of
+-- function calls is already determined in the parser before
+-- rewriting.)
+SELECT * FROM t5 ORDER BY c ASC, a ASC;
+
+
 -- cleanup
 RESET search_path;
 SET client_min_messages TO warning;
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index a41f8b83d77..63a60303659 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -51,7 +51,7 @@ CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
 SELECT * FROM test_like_id_3;  -- identity was copied and applied
 DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 
-CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE test_like_gen_1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 \d test_like_gen_1
 INSERT INTO test_like_gen_1 (a) VALUES (1);
 SELECT * FROM test_like_gen_1;
diff --git a/src/test/regress/sql/fast_default.sql b/src/test/regress/sql/fast_default.sql
index dc9df78a35d..6e7f37b17b2 100644
--- a/src/test/regress/sql/fast_default.sql
+++ b/src/test/regress/sql/fast_default.sql
@@ -66,6 +66,17 @@ CREATE EVENT TRIGGER has_volatile_rewrite
 ALTER TABLE has_volatile ADD col3 timestamptz DEFAULT current_timestamp;
 ALTER TABLE has_volatile ADD col4 int DEFAULT (random() * 10000)::int;
 
+-- virtual generated columns don't need a rewrite
+ALTER TABLE has_volatile ADD col5 int GENERATED ALWAYS AS (tableoid::int + col2) VIRTUAL;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE float8;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+ALTER TABLE has_volatile ALTER COLUMN col5 TYPE numeric;
+-- here, we do need a rewrite
+ALTER TABLE has_volatile ALTER COLUMN col1 SET DATA TYPE float8,
+  ADD COLUMN col6 float8 GENERATED ALWAYS AS (col1 * 4) VIRTUAL;
+-- stored generated columns need a rewrite
+ALTER TABLE has_volatile ADD col7 int GENERATED ALWAYS AS (55) stored;
+
 
 
 -- Test a large sample of different datatypes
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_stored.sql
index 6fbfcbf9615..b7749ce355f 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_stored.sql
@@ -1,3 +1,6 @@
+-- keep these tests aligned with generated_virtual.sql
+
+
 CREATE SCHEMA generated_stored_tests;
 GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
 SET search_path = generated_stored_tests;
@@ -149,6 +152,7 @@ CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 INSERT INTO gtestx (a, x) VALUES (11, 22);
@@ -438,6 +442,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) VIRTUAL  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -447,6 +454,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint DEFAULT 42);
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS IDENTITY);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
@@ -715,4 +725,4 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/generated_stored.sql b/src/test/regress/sql/generated_virtual.sql
similarity index 74%
copy from src/test/regress/sql/generated_stored.sql
copy to src/test/regress/sql/generated_virtual.sql
index 6fbfcbf9615..34870813910 100644
--- a/src/test/regress/sql/generated_stored.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -1,51 +1,54 @@
-CREATE SCHEMA generated_stored_tests;
-GRANT USAGE ON SCHEMA generated_stored_tests TO PUBLIC;
-SET search_path = generated_stored_tests;
+-- keep these tests aligned with generated_stored.sql
 
-CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
-CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
 
-SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2;
+CREATE SCHEMA generated_virtual_tests;
+GRANT USAGE ON SCHEMA generated_virtual_tests TO PUBLIC;
+SET search_path = generated_virtual_tests;
 
-SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_stored_tests' ORDER BY 1, 2, 3;
+CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) VIRTUAL);
+CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+
+SELECT table_name, column_name, column_default, is_nullable, is_generated, generation_expression FROM information_schema.columns WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2;
+
+SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
 \d gtest1
 
 -- duplicate generated
-CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED GENERATED ALWAYS AS (a * 3) STORED);
+CREATE TABLE gtest_err_1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL GENERATED ALWAYS AS (a * 3) VIRTUAL);
 
 -- references to other generated columns, including self-references
-CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) STORED);
-CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (b * 3) STORED);
+CREATE TABLE gtest_err_2a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (b * 2) VIRTUAL);
+CREATE TABLE gtest_err_2b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL, c int GENERATED ALWAYS AS (b * 3) VIRTUAL);
 -- a whole-row var is a self-reference on steroids, so disallow that too
 CREATE TABLE gtest_err_2c (a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) STORED);
+    b int GENERATED ALWAYS AS (num_nulls(gtest_err_2c)) VIRTUAL);
 
 -- invalid reference
-CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) STORED);
+CREATE TABLE gtest_err_3 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (c * 2) VIRTUAL);
 
 -- generation expression must be immutable
-CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) STORED);
+CREATE TABLE gtest_err_4 (a int PRIMARY KEY, b double precision GENERATED ALWAYS AS (random()) VIRTUAL);
 -- ... but be sure that the immutability test is accurate
-CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') STORED);
+CREATE TABLE gtest2 (a int, b text GENERATED ALWAYS AS (a || ' sec') VIRTUAL);
 DROP TABLE gtest2;
 
 -- cannot have default/identity and generated
-CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) STORED);
-CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_err_5a (a int PRIMARY KEY, b int DEFAULT 5 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+CREATE TABLE gtest_err_5b (a int PRIMARY KEY, b int GENERATED ALWAYS AS identity GENERATED ALWAYS AS (a * 2) VIRTUAL);
 
 -- reference to system column not allowed in generated column
 -- (except tableoid, which we test below)
-CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) STORED);
+CREATE TABLE gtest_err_6a (a int PRIMARY KEY, b bool GENERATED ALWAYS AS (xmin <> 37) VIRTUAL);
 
 -- various prohibited constructs
-CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) STORED);
-CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) STORED);
-CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) STORED);
-CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) STORED);
+CREATE TABLE gtest_err_7a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (avg(a)) VIRTUAL);
+CREATE TABLE gtest_err_7b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (row_number() OVER (ORDER BY a)) VIRTUAL);
+CREATE TABLE gtest_err_7c (a int PRIMARY KEY, b int GENERATED ALWAYS AS ((SELECT a)) VIRTUAL);
+CREATE TABLE gtest_err_7d (a int PRIMARY KEY, b int GENERATED ALWAYS AS (generate_series(1, a)) VIRTUAL);
 
 -- GENERATED BY DEFAULT not allowed
-CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) STORED);
+CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a * 2) VIRTUAL);
 
 INSERT INTO gtest1 VALUES (1);
 INSERT INTO gtest1 VALUES (2, DEFAULT);  -- ok
@@ -68,7 +71,7 @@ CREATE TABLE gtest_err_8 (a int PRIMARY KEY, b int GENERATED BY DEFAULT AS (a *
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
--- test that overflow error happens on write
+-- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
 DELETE FROM gtest1 WHERE a = 2000000000;
@@ -91,8 +94,8 @@ CREATE TABLE gtestm (
   id int PRIMARY KEY,
   f1 int,
   f2 int,
-  f3 int GENERATED ALWAYS AS (f1 * 2) STORED,
-  f4 int GENERATED ALWAYS AS (f2 * 2) STORED
+  f3 int GENERATED ALWAYS AS (f1 * 2) VIRTUAL,
+  f4 int GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 );
 INSERT INTO gtestm VALUES (1, 5, 100);
 MERGE INTO gtestm t USING (VALUES (1, 10), (2, 20)) v(id, f1) ON t.id = v.id
@@ -104,7 +107,7 @@ CREATE TABLE gtestm (
 
 CREATE TABLE gtestm (
   a int PRIMARY KEY,
-  b int GENERATED ALWAYS AS (a * 2) STORED
+  b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtestm (a) SELECT g FROM generate_series(1, 10) g;
 MERGE INTO gtestm t USING gtestm AS s ON 2 * t.a = s.b WHEN MATCHED THEN DELETE RETURNING *;
@@ -141,15 +144,16 @@ CREATE TABLE gtest1_1 () INHERITS (gtest1);
 
 -- can't have generated column that is a child of normal column
 CREATE TABLE gtest_normal (a int, b int);
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED) INHERITS (gtest_normal);  -- error
-CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL) INHERITS (gtest_normal);  -- error
+CREATE TABLE gtest_normal_child (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest_normal_child INHERIT gtest_normal;  -- error
 DROP TABLE gtest_normal, gtest_normal_child;
 
 -- test inheritance mismatches between parent and child
 CREATE TABLE gtestx (x int, b int DEFAULT 10) INHERITS (gtest1);  -- error
 CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS IDENTITY) INHERITS (gtest1);  -- error
-CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- ok, overrides parent
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS (gtest1);  -- error
+CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) VIRTUAL) INHERITS (gtest1);  -- ok, overrides parent
 \d+ gtestx
 INSERT INTO gtestx (a, x) VALUES (11, 22);
 SELECT * FROM gtest1;
@@ -157,9 +161,9 @@ CREATE TABLE gtestx (x int, b int GENERATED ALWAYS AS (a * 22) STORED) INHERITS
 
 CREATE TABLE gtestxx_1 (a int NOT NULL, b int);
 ALTER TABLE gtestxx_1 INHERIT gtest1;  -- error
-CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtestxx_3 (a int NOT NULL, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtestxx_3 INHERIT gtest1;  -- ok
-CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) STORED, a int NOT NULL);
+CREATE TABLE gtestxx_4 (b int GENERATED ALWAYS AS (a * 2) VIRTUAL, a int NOT NULL);
 ALTER TABLE gtestxx_4 INHERIT gtest1;  -- ok
 
 -- test multiple inheritance mismatches
@@ -171,28 +175,28 @@ CREATE TABLE gtesty (x int, b int);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
 DROP TABLE gtesty;
 
-CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) STORED);
+CREATE TABLE gtesty (x int, b int GENERATED ALWAYS AS (x * 22) VIRTUAL);
 CREATE TABLE gtest1_y () INHERITS (gtest1, gtesty);  -- error
-CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) STORED) INHERITS (gtest1, gtesty);  -- ok
+CREATE TABLE gtest1_y (b int GENERATED ALWAYS AS (x + 1) VIRTUAL) INHERITS (gtest1, gtesty);  -- ok
 \d gtest1_y
 
 -- test correct handling of GENERATED column that's only in child
 CREATE TABLE gtestp (f1 int);
-CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) STORED) INHERITS(gtestp);
+CREATE TABLE gtestc (f2 int GENERATED ALWAYS AS (f1+1) VIRTUAL) INHERITS(gtestp);
 INSERT INTO gtestc values(42);
 TABLE gtestc;
 UPDATE gtestp SET f1 = f1 * 10;
 TABLE gtestc;
 DROP TABLE gtestp CASCADE;
 
--- test stored update
-CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
+-- test update
+CREATE TABLE gtest3 (a int, b int GENERATED ALWAYS AS (a * 3) VIRTUAL);
 INSERT INTO gtest3 (a) VALUES (1), (2), (3), (NULL);
 SELECT * FROM gtest3 ORDER BY a;
 UPDATE gtest3 SET a = 22 WHERE a = 2;
 SELECT * FROM gtest3 ORDER BY a;
 
-CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED);
+CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) VIRTUAL);
 INSERT INTO gtest3a (a) VALUES ('a'), ('b'), ('c'), (NULL);
 SELECT * FROM gtest3a ORDER BY a;
 UPDATE gtest3a SET a = 'bb' WHERE a = 'b';
@@ -232,12 +236,12 @@ CREATE TABLE gtest3a (a text, b text GENERATED ALWAYS AS (a || '+' || a) STORED)
 SELECT * FROM gtest3 ORDER BY a;
 
 -- null values
-CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) STORED);
+CREATE TABLE gtest2 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (NULL) VIRTUAL);
 INSERT INTO gtest2 VALUES (1);
 SELECT * FROM gtest2;
 
 -- simple column reference for varlena types
-CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED);
+CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) VIRTUAL);
 INSERT INTO gtest_varlena (a) VALUES('01234567890123456789');
 INSERT INTO gtest_varlena (a) VALUES(NULL);
 SELECT * FROM gtest_varlena ORDER BY a;
@@ -247,7 +251,7 @@ CREATE TABLE gtest_varlena (a varchar, b varchar GENERATED ALWAYS AS (a) STORED)
 CREATE TYPE double_int as (a int, b int);
 CREATE TABLE gtest4 (
     a int,
-    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) STORED
+    b double_int GENERATED ALWAYS AS ((a * 2, a * 3)) VIRTUAL
 );
 INSERT INTO gtest4 VALUES (1), (6);
 SELECT * FROM gtest4;
@@ -258,35 +262,35 @@ CREATE TABLE gtest4 (
 -- using tableoid is allowed
 CREATE TABLE gtest_tableoid (
   a int PRIMARY KEY,
-  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) STORED
+  b bool GENERATED ALWAYS AS (tableoid = 'gtest_tableoid'::regclass) VIRTUAL
 );
 INSERT INTO gtest_tableoid VALUES (1), (2);
 ALTER TABLE gtest_tableoid ADD COLUMN
-  c regclass GENERATED ALWAYS AS (tableoid) STORED;
+  c regclass GENERATED ALWAYS AS (tableoid) VIRTUAL;
 SELECT * FROM gtest_tableoid;
 
 -- drop column behavior
-CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest10 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 ALTER TABLE gtest10 DROP COLUMN b;  -- fails
 ALTER TABLE gtest10 DROP COLUMN b CASCADE;  -- drops c too
 
 \d gtest10
 
-CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest10a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest10a DROP COLUMN b;
 INSERT INTO gtest10a (a) VALUES (1);
 
 -- privileges
 CREATE USER regress_user11;
 
-CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) STORED);
+CREATE TABLE gtest11 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (b * 2) VIRTUAL);
 INSERT INTO gtest11 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c) ON gtest11 TO regress_user11;
 
 CREATE FUNCTION gf1(a int) RETURNS int AS $$ SELECT a * 3 $$ IMMUTABLE LANGUAGE SQL;
 REVOKE ALL ON FUNCTION gf1(int) FROM PUBLIC;
 
-CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) STORED);
+CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b)) VIRTUAL);
 INSERT INTO gtest12 VALUES (1, 10), (2, 20);
 GRANT SELECT (a, c), INSERT ON gtest12 TO regress_user11;
 
@@ -294,8 +298,8 @@ CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b
 SELECT a, b FROM gtest11;  -- not allowed
 SELECT a, c FROM gtest11;  -- allowed
 SELECT gf1(10);  -- not allowed
-INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- currently not allowed because of function permissions, should arguably be allowed
-SELECT a, c FROM gtest12;  -- allowed (does not actually invoke the function)
+INSERT INTO gtest12 VALUES (3, 30), (4, 40);  -- allowed (does not actually invoke the function)
+SELECT a, c FROM gtest12;  -- currently not allowed because of function permissions, should arguably be allowed
 RESET ROLE;
 
 DROP FUNCTION gf1(int);  -- fail
@@ -304,133 +308,139 @@ CREATE TABLE gtest12 (a int PRIMARY KEY, b int, c int GENERATED ALWAYS AS (gf1(b
 DROP USER regress_user11;
 
 -- check constraints
-CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED CHECK (b < 50));
+CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL CHECK (b < 50));
 INSERT INTO gtest20 (a) VALUES (10);  -- ok
 INSERT INTO gtest20 (a) VALUES (30);  -- violates constraint
 
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint
-ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100);  -- violates constraint (currently not supported)
+ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3);  -- ok (currently not supported)
 
-CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20a (a) VALUES (10);
 INSERT INTO gtest20a (a) VALUES (30);
 ALTER TABLE gtest20a ADD CHECK (b < 50);  -- fails on existing row
 
-CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 INSERT INTO gtest20b (a) VALUES (10);
 INSERT INTO gtest20b (a) VALUES (30);
 ALTER TABLE gtest20b ADD CONSTRAINT chk CHECK (b < 50) NOT VALID;
 ALTER TABLE gtest20b VALIDATE CONSTRAINT chk;  -- fails on existing row
 
 -- check with whole-row reference
-CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
+CREATE TABLE gtest20c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
 ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL);
 INSERT INTO gtest20c VALUES (1);  -- ok
 INSERT INTO gtest20c VALUES (NULL);  -- fails
 
--- not-null constraints
-CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED NOT NULL);
-INSERT INTO gtest21a (a) VALUES (1);  -- ok
-INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
+-- not-null constraints (currently not supported)
+CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
+--INSERT INTO gtest21a (a) VALUES (1);  -- ok
+--INSERT INTO gtest21a (a) VALUES (0);  -- violates constraint
 
-CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) STORED);
+-- also check with table constraint syntax
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);  -- error
+CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
+ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;  -- error
+DROP TABLE gtest21ax;
+
+CREATE TABLE gtest21b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
 ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
-INSERT INTO gtest21b (a) VALUES (1);  -- ok
-INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
+--INSERT INTO gtest21b (a) VALUES (1);  -- ok
+--INSERT INTO gtest21b (a) VALUES (0);  -- violates constraint
 ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
-INSERT INTO gtest21b (a) VALUES (0);  -- ok now
+--INSERT INTO gtest21b (a) VALUES (0);  -- ok now
 
 -- index constraints
-CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) STORED UNIQUE);
-INSERT INTO gtest22a VALUES (2);
-INSERT INTO gtest22a VALUES (3);
-INSERT INTO gtest22a VALUES (4);
-CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) STORED, PRIMARY KEY (a, b));
-INSERT INTO gtest22b VALUES (2);
-INSERT INTO gtest22b VALUES (2);
+CREATE TABLE gtest22a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a / 2) VIRTUAL UNIQUE);
+--INSERT INTO gtest22a VALUES (2);
+--INSERT INTO gtest22a VALUES (3);
+--INSERT INTO gtest22a VALUES (4);
+CREATE TABLE gtest22b (a int, b int GENERATED ALWAYS AS (a / 2) VIRTUAL, PRIMARY KEY (a, b));
+--INSERT INTO gtest22b VALUES (2);
+--INSERT INTO gtest22b VALUES (2);
 
 -- indexes
-CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
-CREATE INDEX gtest22c_b_idx ON gtest22c (b);
-CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
-CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
-\d gtest22c
-
-INSERT INTO gtest22c VALUES (1), (2), (3);
-SET enable_seqscan TO off;
-SET enable_bitmapscan TO off;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
-SELECT * FROM gtest22c WHERE b = 4;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
-SELECT * FROM gtest22c WHERE b * 3 = 6;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-
-ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
-ANALYZE gtest22c;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
-SELECT * FROM gtest22c WHERE b = 8;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
-SELECT * FROM gtest22c WHERE b * 3 = 12;
-EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
-RESET enable_seqscan;
-RESET enable_bitmapscan;
+CREATE TABLE gtest22c (a int, b int GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--CREATE INDEX gtest22c_b_idx ON gtest22c (b);
+--CREATE INDEX gtest22c_expr_idx ON gtest22c ((b * 3));
+--CREATE INDEX gtest22c_pred_idx ON gtest22c (a) WHERE b > 0;
+--\d gtest22c
+
+--INSERT INTO gtest22c VALUES (1), (2), (3);
+--SET enable_seqscan TO off;
+--SET enable_bitmapscan TO off;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 4;
+--SELECT * FROM gtest22c WHERE b = 4;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
+--SELECT * FROM gtest22c WHERE b * 3 = 6;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+
+--ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
+--ANALYZE gtest22c;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
+--SELECT * FROM gtest22c WHERE b = 8;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
+--SELECT * FROM gtest22c WHERE b * 3 = 12;
+--EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
+--RESET enable_seqscan;
+--RESET enable_bitmapscan;
 
 -- foreign keys
 CREATE TABLE gtest23a (x int PRIMARY KEY, y int);
-INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
+--INSERT INTO gtest23a VALUES (1, 11), (2, 22), (3, 33);
 
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
-CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON UPDATE CASCADE);  -- error
+CREATE TABLE gtest23x (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x) ON DELETE SET NULL);  -- error
 
-CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED REFERENCES gtest23a (x));
-\d gtest23b
+CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTUAL REFERENCES gtest23a (x));
+--\d gtest23b
 
-INSERT INTO gtest23b VALUES (1);  -- ok
-INSERT INTO gtest23b VALUES (5);  -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
-ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
+--INSERT INTO gtest23b VALUES (1);  -- ok
+--INSERT INTO gtest23b VALUES (5);  -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
+--ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
 
-DROP TABLE gtest23b;
-DROP TABLE gtest23a;
+--DROP TABLE gtest23b;
+--DROP TABLE gtest23a;
 
-CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
-INSERT INTO gtest23p VALUES (1), (2), (3);
+CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL, PRIMARY KEY (y));
+--INSERT INTO gtest23p VALUES (1), (2), (3);
 
 CREATE TABLE gtest23q (a int PRIMARY KEY, b int REFERENCES gtest23p (y));
-INSERT INTO gtest23q VALUES (1, 2);  -- ok
-INSERT INTO gtest23q VALUES (2, 5);  -- error
+--INSERT INTO gtest23q VALUES (1, 2);  -- ok
+--INSERT INTO gtest23q VALUES (2, 5);  -- error
 
 -- domains
 CREATE DOMAIN gtestdomain1 AS int CHECK (VALUE < 10);
-CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) STORED);
-INSERT INTO gtest24 (a) VALUES (4);  -- ok
-INSERT INTO gtest24 (a) VALUES (6);  -- error
+CREATE TABLE gtest24 (a int PRIMARY KEY, b gtestdomain1 GENERATED ALWAYS AS (a * 2) VIRTUAL);
+--INSERT INTO gtest24 (a) VALUES (4);  -- ok
+--INSERT INTO gtest24 (a) VALUES (6);  -- error
 CREATE TYPE gtestdomain1range AS range (subtype = gtestdomain1);
-CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) STORED);
-INSERT INTO gtest24r (a) VALUES (4);  -- ok
-INSERT INTO gtest24r (a) VALUES (6);  -- error
+CREATE TABLE gtest24r (a int PRIMARY KEY, b gtestdomain1range GENERATED ALWAYS AS (gtestdomain1range(a, a + 5)) VIRTUAL);
+--INSERT INTO gtest24r (a) VALUES (4);  -- ok
+--INSERT INTO gtest24r (a) VALUES (6);  -- error
 
 -- typed tables (currently not supported)
 CREATE TYPE gtest_type AS (f1 integer, f2 text, f3 bigint);
-CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) STORED);
+CREATE TABLE gtest28 OF gtest_type (f1 WITH OPTIONS GENERATED ALWAYS AS (f2 *2) VIRTUAL);
 DROP TYPE gtest_type CASCADE;
 
 -- partitioning cases
 CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) STORED
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 2) VIRTUAL
 ) FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
-CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED);
+CREATE TABLE gtest_child (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child FOR VALUES FROM ('2016-07-01') TO ('2016-08-01'); -- error
 DROP TABLE gtest_parent, gtest_child;
 
-CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f1);
+CREATE TABLE gtest_parent (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f1);
 CREATE TABLE gtest_child PARTITION OF gtest_parent
   FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');  -- inherits gen expr
 CREATE TABLE gtest_child2 PARTITION OF gtest_parent (
-    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) STORED  -- overrides gen expr
+    f3 WITH OPTIONS GENERATED ALWAYS AS (f2 * 22) VIRTUAL  -- overrides gen expr
 ) FOR VALUES FROM ('2016-08-01') TO ('2016-09-01');
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 DEFAULT 42  -- error
@@ -438,6 +448,9 @@ CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
 CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
     f3 WITH OPTIONS GENERATED ALWAYS AS IDENTITY  -- error
 ) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
+CREATE TABLE gtest_child3 PARTITION OF gtest_parent (
+    f3 GENERATED ALWAYS AS (f2 * 2) STORED  -- error
+) FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
@@ -448,6 +461,9 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
 DROP TABLE gtest_child3;
 CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) STORED);
+ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01'); -- error
+DROP TABLE gtest_child3;
+CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 33) VIRTUAL);
 ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09-01') TO ('2016-10-01');
 \d gtest_child
 \d gtest_child2
@@ -457,7 +473,7 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
 SELECT tableoid::regclass, * FROM gtest_child ORDER BY 1, 2, 3;
-SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;
+SELECT tableoid::regclass, * FROM gtest_child2 ORDER BY 1, 2, 3;  -- uses child's generation expression, not parent's
 SELECT tableoid::regclass, * FROM gtest_child3 ORDER BY 1, 2, 3;
 UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
 SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
@@ -481,21 +497,21 @@ CREATE TABLE gtest_child3 (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWA
 -- we leave these tables around for purposes of testing dump/reload/upgrade
 
 -- generated columns in partition key (not allowed)
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE (f3);
-CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) STORED) PARTITION BY RANGE ((f3 * 3));
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE (f3);
+CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED ALWAYS AS (f2 * 2) VIRTUAL) PARTITION BY RANGE ((f3 * 3));
 
 -- ALTER TABLE ... ADD COLUMN
 CREATE TABLE gtest25 (a int PRIMARY KEY);
 INSERT INTO gtest25 VALUES (3), (4);
-ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
+ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) VIRTUAL, ALTER COLUMN b SET EXPRESSION AS (a * 3);
 SELECT * FROM gtest25 ORDER BY a;
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED;  -- error
-ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) VIRTUAL;  -- error
+ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) VIRTUAL;  -- error
 ALTER TABLE gtest25 ADD COLUMN c int DEFAULT 42,
-  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) STORED;
+  ADD COLUMN x int GENERATED ALWAYS AS (c * 4) VIRTUAL;
 ALTER TABLE gtest25 ADD COLUMN d int DEFAULT 101;
 ALTER TABLE gtest25 ALTER COLUMN d SET DATA TYPE float8,
-  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) STORED;
+  ADD COLUMN y float8 GENERATED ALWAYS AS (d * 4) VIRTUAL;
 SELECT * FROM gtest25 ORDER BY a;
 \d gtest25
 
@@ -503,7 +519,7 @@ CREATE TABLE gtest25 (a int PRIMARY KEY);
 CREATE TABLE gtest27 (
     a int,
     b int,
-    x int GENERATED ALWAYS AS ((a + b) * 2) STORED
+    x int GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL
 );
 INSERT INTO gtest27 (a, b) VALUES (3, 7), (4, 11);
 ALTER TABLE gtest27 ALTER COLUMN a TYPE text;  -- error
@@ -517,7 +533,7 @@ CREATE TABLE gtest27 (
   DROP COLUMN x,
   ALTER COLUMN a TYPE bigint,
   ALTER COLUMN b TYPE bigint,
-  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) STORED;
+  ADD COLUMN x bigint GENERATED ALWAYS AS ((a + b) * 2) VIRTUAL;
 \d gtest27
 -- Ideally you could just do this, but not today (and should x change type?):
 ALTER TABLE gtest27
@@ -529,7 +545,7 @@ CREATE TABLE gtest27 (
 -- ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
 CREATE TABLE gtest29 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 INSERT INTO gtest29 (a) VALUES (3), (4);
 SELECT * FROM gtest29;
@@ -543,20 +559,20 @@ CREATE TABLE gtest29 (
 SELECT * FROM gtest29;
 \d gtest29
 
-ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
+ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;  -- not supported
 INSERT INTO gtest29 (a) VALUES (5);
 INSERT INTO gtest29 (a, b) VALUES (6, 66);
 SELECT * FROM gtest29;
 \d gtest29
 
 -- check that dependencies between columns have also been removed
-ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
-\d gtest29
+--ALTER TABLE gtest29 DROP COLUMN a;  -- should not drop b
+--\d gtest29
 
 -- with inheritance
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30 ALTER COLUMN b DROP EXPRESSION;
@@ -565,7 +581,7 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 DROP TABLE gtest30 CASCADE;
 CREATE TABLE gtest30 (
     a int,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE ONLY gtest30 ALTER COLUMN b DROP EXPRESSION;  -- error
@@ -574,13 +590,13 @@ CREATE TABLE gtest30_1 () INHERITS (gtest30);
 ALTER TABLE gtest30_1 ALTER COLUMN b DROP EXPRESSION;  -- error
 
 -- composite type dependencies
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 DROP TABLE gtest31_1, gtest31_2;
 
 -- Check it for a partitioned table, too
-CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') STORED, c text) PARTITION BY LIST (a);
+CREATE TABLE gtest31_1 (a int, b text GENERATED ALWAYS AS ('hello') VIRTUAL, c text) PARTITION BY LIST (a);
 CREATE TABLE gtest31_2 (x int, y gtest31_1);
 ALTER TABLE gtest31_1 ALTER COLUMN b TYPE varchar;  -- fails
 DROP TABLE gtest31_1, gtest31_2;
@@ -588,7 +604,7 @@ CREATE TABLE gtest31_2 (x int, y gtest31_1);
 -- triggers
 CREATE TABLE gtest26 (
     a int PRIMARY KEY,
-    b int GENERATED ALWAYS AS (a * 2) STORED
+    b int GENERATED ALWAYS AS (a * 2) VIRTUAL
 );
 
 CREATE FUNCTION gtest_trigger_func() RETURNS trigger
@@ -704,7 +720,7 @@ CREATE TABLE gtest28a (
   a int,
   b int,
   c int,
-  x int GENERATED ALWAYS AS (b * 2) STORED
+  x int GENERATED ALWAYS AS (b * 2) VIRTUAL
 );
 
 ALTER TABLE gtest28a DROP COLUMN a;
@@ -715,4 +731,4 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 
 -- sanity check of system catalog
-SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's');
+SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
diff --git a/src/test/regress/sql/publication.sql b/src/test/regress/sql/publication.sql
index 47f0329c244..22ffb86747e 100644
--- a/src/test/regress/sql/publication.sql
+++ b/src/test/regress/sql/publication.sql
@@ -214,7 +214,7 @@ CREATE FUNCTION testpub_rf_func1(integer, integer) RETURNS boolean AS $$ SELECT
 CREATE OPERATOR =#> (PROCEDURE = testpub_rf_func1, LEFTARG = integer, RIGHTARG = integer);
 CREATE PUBLICATION testpub6 FOR TABLE testpub_rf_tbl3 WHERE (e =#> 27);
 -- fail - user-defined functions are not allowed
-CREATE FUNCTION testpub_rf_func2() RETURNS integer AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
+CREATE FUNCTION testpub_rf_func2() RETURNS integer IMMUTABLE AS $$ BEGIN RETURN 123; END; $$ LANGUAGE plpgsql;
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a >= testpub_rf_func2());
 -- fail - non-immutable functions are not allowed. random() is volatile.
 ALTER PUBLICATION testpub5 ADD TABLE testpub_rf_tbl1 WHERE (a < random());
@@ -261,18 +261,30 @@ CREATE PUBLICATION testpub6 FOR TABLES IN SCHEMA testpub_rf_schema2;
 ALTER PUBLICATION testpub6 SET TABLES IN SCHEMA testpub_rf_schema2, TABLE testpub_rf_schema2.testpub_rf_tbl6 WHERE (i < 99);
 RESET client_min_messages;
 \dRp+ testpub6
+-- fail - virtual generated column uses user-defined function
+CREATE TABLE testpub_rf_tbl6 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * testpub_rf_func2()) VIRTUAL);
+CREATE PUBLICATION testpub7 FOR TABLE testpub_rf_tbl6 WHERE (y > 100);
+-- test that SET EXPRESSION is rejected, because it could affect a row filter
+SET client_min_messages = 'ERROR';
+CREATE TABLE testpub_rf_tbl7 (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 111) VIRTUAL);
+CREATE PUBLICATION testpub8 FOR TABLE testpub_rf_tbl7 WHERE (y > 100);
+ALTER TABLE testpub_rf_tbl7 ALTER COLUMN y SET EXPRESSION AS (x * testpub_rf_func2());
+RESET client_min_messages;
 
 DROP TABLE testpub_rf_tbl1;
 DROP TABLE testpub_rf_tbl2;
 DROP TABLE testpub_rf_tbl3;
 DROP TABLE testpub_rf_tbl4;
 DROP TABLE testpub_rf_tbl5;
+DROP TABLE testpub_rf_tbl6;
 DROP TABLE testpub_rf_schema1.testpub_rf_tbl5;
 DROP TABLE testpub_rf_schema2.testpub_rf_tbl6;
 DROP SCHEMA testpub_rf_schema1;
 DROP SCHEMA testpub_rf_schema2;
 DROP PUBLICATION testpub5;
 DROP PUBLICATION testpub6;
+DROP PUBLICATION testpub8;
+DROP TABLE testpub_rf_tbl7;
 DROP OPERATOR =#>(integer, integer);
 DROP FUNCTION testpub_rf_func1(integer, integer);
 DROP FUNCTION testpub_rf_func2();
@@ -435,7 +447,9 @@ CREATE PUBLICATION testpub_fortable FOR TABLE testpub_tbl1;
 CREATE PUBLICATION testpub_fortable_insert WITH (publish = 'insert');
 RESET client_min_messages;
 CREATE TABLE testpub_tbl5 (a int PRIMARY KEY, b text, c text,
-	d int generated always as (a + length(b)) stored);
+    d int generated always as (a + length(b)) stored,
+    e int generated always as (a + length(b)) virtual
+);
 -- error: column "x" does not exist
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, x);
 -- error: replica identity "a" not included in the column list
@@ -462,9 +476,11 @@ CREATE UNIQUE INDEX testpub_tbl5_b_key ON testpub_tbl5 (b, c);
 UPDATE testpub_tbl5 SET a = 1;
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
 
--- ok: generated column "d" can be in the list too
+-- ok: stored generated column "d" can be in the list too
 ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, d);
 ALTER PUBLICATION testpub_fortable DROP TABLE testpub_tbl5;
+-- error: virtual generated column "e" can't be in list
+ALTER PUBLICATION testpub_fortable ADD TABLE testpub_tbl5 (a, e);
 
 -- error: change the replica identity to "b", and column list to (a, c)
 -- then update fails, because (a, c) does not cover replica identity
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index cf09f62eaba..f61dbbf9581 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -2072,6 +2072,33 @@ CREATE POLICY p3 ON r1 FOR INSERT WITH CHECK (true);
 
 DROP TABLE r1;
 
+--
+-- Test policies using virtual generated columns
+--
+SET SESSION AUTHORIZATION regress_rls_alice;
+SET row_security = on;
+CREATE TABLE r1 (a int, b int GENERATED ALWAYS AS (a * 10) VIRTUAL);
+ALTER TABLE r1 ADD c int GENERATED ALWAYS AS (a * 100) VIRTUAL;
+INSERT INTO r1 VALUES (1), (2), (4);
+
+CREATE POLICY p0 ON r1 USING (b * 10 = c);
+CREATE POLICY p1 ON r1 AS RESTRICTIVE USING (b > 10);
+CREATE POLICY p2 ON r1 AS RESTRICTIVE USING ((SELECT c) < 400);
+ALTER TABLE r1 ENABLE ROW LEVEL SECURITY;
+ALTER TABLE r1 FORCE ROW LEVEL SECURITY;
+
+-- Should fail p1
+INSERT INTO r1 VALUES (0);
+
+-- Should fail p2
+INSERT INTO r1 VALUES (4);
+
+-- OK
+INSERT INTO r1 VALUES (3);
+SELECT * FROM r1;
+
+DROP TABLE r1;
+
 -- Check dependency handling
 RESET SESSION AUTHORIZATION;
 CREATE TABLE dep1 (c1 int);
diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql
index 5c786b16c6f..75b04e5a136 100644
--- a/src/test/regress/sql/stats_ext.sql
+++ b/src/test/regress/sql/stats_ext.sql
@@ -45,6 +45,20 @@ CREATE STATISTICS tst ON (y) FROM ext_stats_test; -- single column reference
 CREATE STATISTICS tst ON y + z FROM ext_stats_test; -- missing parentheses
 CREATE STATISTICS tst ON (x, y) FROM ext_stats_test; -- tuple expression
 DROP TABLE ext_stats_test;
+-- statistics on virtual generated column not allowed
+CREATE TABLE ext_stats_test1 (x int, y int, z int GENERATED ALWAYS AS (x+y) VIRTUAL, w xid);
+CREATE STATISTICS tst on z from ext_stats_test1;
+CREATE STATISTICS tst on (z) from ext_stats_test1;
+CREATE STATISTICS tst on (z+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON z from ext_stats_test1;
+-- statistics on system column not allowed
+CREATE STATISTICS tst on tableoid from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid) from ext_stats_test1;
+CREATE STATISTICS tst on (tableoid::int+1) from ext_stats_test1;
+CREATE STATISTICS tst (ndistinct) ON xmin from ext_stats_test1;
+-- statistics without a less-than operator not supported
+CREATE STATISTICS tst (ndistinct) ON w from ext_stats_test1;
+DROP TABLE ext_stats_test1;
 
 -- Ensure stats are dropped sanely, and test IF NOT EXISTS while at it
 CREATE TABLE ab1 (a INTEGER, b INTEGER, c INTEGER);
diff --git a/src/test/subscription/t/011_generated.pl b/src/test/subscription/t/011_generated.pl
index 5970bb47360..c7a4c52e4f2 100644
--- a/src/test/subscription/t/011_generated.pl
+++ b/src/test/subscription/t/011_generated.pl
@@ -21,11 +21,11 @@
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
 
 $node_publisher->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED, c int GENERATED ALWAYS AS (a * 3) VIRTUAL)"
 );
 
 $node_subscriber->safe_psql('postgres',
-	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int)"
+	"CREATE TABLE tab1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 22) STORED, c int GENERATED ALWAYS AS (a * 33) VIRTUAL, d int)"
 );
 
 # data for initial sync
@@ -42,10 +42,11 @@
 # Wait for initial sync of all subscriptions
 $node_subscriber->wait_for_subscription_sync;
 
-my $result = $node_subscriber->safe_psql('postgres', "SELECT a, b FROM tab1");
-is( $result, qq(1|22
-2|44
-3|66), 'generated columns initial sync');
+my $result =
+  $node_subscriber->safe_psql('postgres', "SELECT a, b, c FROM tab1");
+is( $result, qq(1|22|33
+2|44|66
+3|66|99), 'generated columns initial sync');
 
 # data to replicate
 
@@ -56,11 +57,11 @@
 $node_publisher->wait_for_catchup('sub1');
 
 $result = $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|), 'generated columns replicated');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|), 'generated columns replicated');
 
 # try it with a subscriber-side trigger
 
@@ -69,7 +70,7 @@
 CREATE FUNCTION tab1_trigger_func() RETURNS trigger
 LANGUAGE plpgsql AS $$
 BEGIN
-  NEW.c := NEW.a + 10;
+  NEW.d := NEW.a + 10;
   RETURN NEW;
 END $$;
 
@@ -88,13 +89,13 @@ BEGIN
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT * FROM tab1 ORDER BY 1");
-is( $result, qq(1|22|
-2|44|
-3|66|
-4|88|
-6|132|
-8|176|18
-9|198|19), 'generated columns replicated with trigger');
+is( $result, qq(1|22|33|
+2|44|66|
+3|66|99|
+4|88|132|
+6|132|198|
+8|176|264|18
+9|198|297|19), 'generated columns replicated with trigger');
 
 # cleanup
 $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION sub1");
diff --git a/src/test/subscription/t/028_row_filter.pl b/src/test/subscription/t/028_row_filter.pl
index e3a6d69da7e..e2c83670053 100644
--- a/src/test/subscription/t/028_row_filter.pl
+++ b/src/test/subscription/t/028_row_filter.pl
@@ -240,6 +240,9 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync PARTITION OF tab_rowfilter_parent_sync FOR VALUES FROM (1) TO (20)"
 );
+$node_publisher->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup structure on subscriber
 $node_subscriber->safe_psql('postgres',
@@ -294,6 +297,9 @@
 	"CREATE TABLE tab_rowfilter_parent_sync (a int)");
 $node_subscriber->safe_psql('postgres',
 	"CREATE TABLE tab_rowfilter_child_sync (a int)");
+$node_subscriber->safe_psql('postgres',
+	"CREATE TABLE tab_rowfilter_virtual (id int PRIMARY KEY, x int, y int GENERATED ALWAYS AS (x * 2) VIRTUAL)"
+);
 
 # setup logical replication
 $node_publisher->safe_psql('postgres',
@@ -359,6 +365,11 @@
 	"CREATE PUBLICATION tap_pub_child_sync FOR TABLE tab_rowfilter_child_sync WHERE (a < 15)"
 );
 
+# publication using virtual generated column in row filter expression
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION tap_pub_virtual FOR TABLE tab_rowfilter_virtual WHERE (y > 10)"
+);
+
 #
 # The following INSERTs are executed before the CREATE SUBSCRIPTION, so these
 # SQL commands are for testing the initial data copy using logical replication.
@@ -407,8 +418,12 @@
 	"INSERT INTO tab_rowfilter_child(a, b) VALUES(0,'0'),(30,'30'),(40,'40')"
 );
 
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (1, 2), (2, 4), (3, 6)"
+);
+
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub_1, tap_pub_2, tap_pub_3, tap_pub_4a, tap_pub_4b, tap_pub_5a, tap_pub_5b, tap_pub_toast, tap_pub_inherits, tap_pub_viaroot_2, tap_pub_viaroot_1, tap_pub_parent_sync, tap_pub_child_sync, tap_pub_virtual"
 );
 
 # wait for initial table synchronization to finish
@@ -550,6 +565,16 @@
 	"SELECT a FROM tab_rowfilter_child_sync ORDER BY 1");
 is($result, qq(), 'check initial data copy from tab_rowfilter_child_sync');
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (1, 2)      NO, 2 * 2 <= 10
+# - INSERT (2, 4)      NO, 4 * 2 <= 10
+# - INSERT (3, 6)      YES, 6 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is($result, qq(3|6),
+	'check initial data copy from table tab_rowfilter_virtual');
+
 # The following commands are executed after CREATE SUBSCRIPTION, so these SQL
 # commands are for testing normal logical replication behavior.
 #
@@ -582,6 +607,8 @@
 	"INSERT INTO tab_rowfilter_child (a, b) VALUES (13, '13'), (17, '17')");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rowfilter_viaroot_part (a) VALUES (14), (15), (16)");
+$node_publisher->safe_psql('postgres',
+	"INSERT INTO tab_rowfilter_virtual (id, x) VALUES (4, 3), (5, 7)");
 
 $node_publisher->wait_for_catchup($appname);
 
@@ -725,6 +752,15 @@
 	'check replicated rows to tab_rowfilter_inherited and tab_rowfilter_child'
 );
 
+# Check expected replicated rows for tab_rowfilter_virtual
+# tap_pub_virtual filter is: (y > 10), where y is generated as (x * 2)
+# - INSERT (4, 3)      NO, 3 * 2 <= 10
+# - INSERT (5, 7)      YES, 7 * 2 > 10
+$result = $node_subscriber->safe_psql('postgres',
+	"SELECT id, x FROM tab_rowfilter_virtual ORDER BY id");
+is( $result, qq(3|6
+5|7), 'check replicated rows to tab_rowfilter_virtual');
+
 # UPDATE the non-toasted column for table tab_rowfilter_toast
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_rowfilter_toast SET b = '1'");
diff --git a/src/test/subscription/t/031_column_list.pl b/src/test/subscription/t/031_column_list.pl
index 7a535e76b08..e859bcdf4eb 100644
--- a/src/test/subscription/t/031_column_list.pl
+++ b/src/test/subscription/t/031_column_list.pl
@@ -1209,7 +1209,7 @@
 # list) are considered to have the same column list.
 $node_publisher->safe_psql(
 	'postgres', qq(
-	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED);
+	CREATE TABLE test_mix_4 (a int PRIMARY KEY, b int, c int, d int GENERATED ALWAYS AS (a + 1) STORED, e int GENERATED ALWAYS AS (a + 2) VIRTUAL);
 	ALTER TABLE test_mix_4 DROP COLUMN c;
 
 	CREATE PUBLICATION pub_mix_7 FOR TABLE test_mix_4 (a, b);

base-commit: 622f678c10202c8a0b350794d504eeef7b773e90
-- 
2.48.1

From 749b7adbf7bbfbf6428f99be57b7dce2f52f51db Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 4 Feb 2025 17:31:42 +0100
Subject: [PATCH v14 2/3] Fixup review Shlok Kyal 2025-01-28

---
 src/backend/commands/publicationcmds.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 801560c8fdc..06fb1823963 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -405,6 +405,14 @@ pub_contains_invalid_column(Oid pubid, Relation relation, List *ancestors,
 			relation->rd_att->constr->has_generated_stored)
 			*invalid_gen_col = true;
 
+		/*
+		 * Virtual generated columns are currently not supported for logical
+		 * replication at all.
+		 */
+		if (relation->rd_att->constr &&
+			relation->rd_att->constr->has_generated_virtual)
+			*invalid_gen_col = true;
+
 		if (*invalid_gen_col && *invalid_column_list)
 			return true;
 	}
@@ -431,7 +439,16 @@ pub_contains_invalid_column(Oid pubid, Relation relation, List *ancestors,
 			 * The publish_generated_columns option must be set to stored if
 			 * the REPLICA IDENTITY contains any stored generated column.
 			 */
-			if (pubgencols_type != PUBLISH_GENCOLS_STORED && att->attgenerated)
+			if (att->attgenerated == ATTRIBUTE_GENERATED_STORED && pubgencols_type != PUBLISH_GENCOLS_STORED)
+			{
+				*invalid_gen_col = true;
+				break;
+			}
+			/*
+			 * The equivalent setting for virtual generated columns does not
+			 * exist yet.
+			 */
+			if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			{
 				*invalid_gen_col = true;
 				break;
-- 
2.48.1

From f1eaccf4eaafddedf2db16d6005f9ced705dd3ec Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 4 Feb 2025 23:35:22 +0100
Subject: [PATCH v14 3/3] Fixup review Dean Rasheed 2025-01-27

---
 src/backend/executor/execUtils.c       | 2 +-
 src/backend/executor/nodeModifyTable.c | 4 ++--
 src/include/nodes/execnodes.h          | 5 ++---
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 123d3c79b43..7eab229dde9 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -1383,7 +1383,7 @@ Bitmapset *
 ExecGetExtraUpdatedCols(ResultRelInfo *relinfo, EState *estate)
 {
 	/* Compute the info if we didn't already */
-	if (!relinfo->ri_Generated_valid)
+	if (!relinfo->ri_extraUpdatedCols_valid)
 		ExecInitGenerated(relinfo, estate, CMD_UPDATE);
 	return relinfo->ri_extraUpdatedCols;
 }
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 2d490cf7ca5..5bf522cac1a 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -501,6 +501,8 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 
 		resultRelInfo->ri_GeneratedExprsU = ri_GeneratedExprs;
 		resultRelInfo->ri_NumGeneratedNeededU = ri_NumGeneratedNeeded;
+
+		resultRelInfo->ri_extraUpdatedCols_valid = true;
 	}
 	else
 	{
@@ -511,8 +513,6 @@ ExecInitGenerated(ResultRelInfo *resultRelInfo,
 		resultRelInfo->ri_NumGeneratedNeededI = ri_NumGeneratedNeeded;
 	}
 
-	resultRelInfo->ri_Generated_valid = true;
-
 	MemoryContextSwitchTo(oldContext);
 }
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index fe6070381f6..62166561d37 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -490,6 +490,8 @@ typedef struct ResultRelInfo
 
 	/* For UPDATE, attnums of generated columns to be computed */
 	Bitmapset  *ri_extraUpdatedCols;
+	/* true if the above has been computed */
+	bool		ri_extraUpdatedCols_valid;
 
 	/* Projection to generate new tuple in an INSERT/UPDATE */
 	ProjectionInfo *ri_projectNew;
@@ -556,9 +558,6 @@ typedef struct ResultRelInfo
 	int			ri_NumGeneratedNeededI;
 	int			ri_NumGeneratedNeededU;
 
-	/* true if the above have been computed */
-	bool		ri_Generated_valid;
-
 	/* list of RETURNING expressions */
 	List	   *ri_returningList;
 
-- 
2.48.1

From 78f272701afb23994021a0b98fa6deaf9d37cc04 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 10 Feb 2025 12:51:17 +0800
Subject: [PATCH v1 1/1] fix expand virtual generated column Var node
 varnullingrels field

discussion: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
---
 src/backend/rewrite/rewriteManip.c            | 54 +++++++++++++++++++
 src/include/rewrite/rewriteManip.h            |  2 +
 .../regress/expected/generated_virtual.out    | 37 +++++++++++++
 src/test/regress/sql/generated_virtual.sql    |  9 ++++
 src/tools/pgindent/typedefs.list              |  1 +
 5 files changed, 103 insertions(+)

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index a115b217c9..9d81d5441a 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -766,6 +766,41 @@ typedef struct
 	int			min_sublevels_up;
 } IncrementVarSublevelsUp_context;
 
+typedef struct
+{
+	int			sublevels_up;
+	Bitmapset *varnullingrels;
+} SetVarNullingrels_context;
+
+static bool
+SetVarNullingrels_walker(Node *node,
+						 SetVarNullingrels_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varlevelsup == context->sublevels_up)
+			var->varnullingrels = bms_union(context->varnullingrels, var->varnullingrels);
+
+		return false;
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		context->sublevels_up++;
+		result = query_tree_walker((Query *) node, SetVarNullingrels_walker,
+								   context, 0);
+		context->sublevels_up--;
+		return result;
+	}
+	return expression_tree_walker(node, SetVarNullingrels_walker, context);
+}
+
 static bool
 IncrementVarSublevelsUp_walker(Node *node,
 							   IncrementVarSublevelsUp_context *context)
@@ -846,6 +881,21 @@ IncrementVarSublevelsUp_walker(Node *node,
 	return expression_tree_walker(node, IncrementVarSublevelsUp_walker, context);
 }
 
+void
+SetVarNullingrels(Node *node, int sublevels_up, Bitmapset *varnullingrels)
+{
+	SetVarNullingrels_context context;
+
+	context.sublevels_up = sublevels_up;
+	context.varnullingrels = varnullingrels;
+
+	/* Expect to start with an expression */
+	query_or_expression_tree_walker(node,
+									SetVarNullingrels_walker,
+									&context,
+									QTW_EXAMINE_RTES_BEFORE);
+}
+
 void
 IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 						int min_sublevels_up)
@@ -1832,6 +1882,10 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		if (var->varlevelsup > 0)
 			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
 
+		if (var->varnullingrels != NULL)
+			SetVarNullingrels((Node *) newnode, var->varlevelsup,
+							  var->varnullingrels);
+
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 512823033b..cca38a6fd7 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -48,6 +48,8 @@ extern void ChangeVarNodes(Node *node, int rt_index, int new_index,
 						   int sublevels_up);
 extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 									int min_sublevels_up);
+extern void SetVarNullingrels(Node *node, int sublevels_up,
+							  Bitmapset *varnullingrels);
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 8660904a34..d6fe82fb13 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -181,6 +181,43 @@ SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
  22 | 2 | 2 | 4
 (2 rows)
 
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+   6
+   6
+   6
+(6 rows)
+
 DROP TABLE gtestx;
 -- test UPDATE/DELETE quals
 SELECT * FROM gtest1 ORDER BY a;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 3207e5cb1f..10638b29f8 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -80,6 +80,15 @@ DELETE FROM gtest1 WHERE a = 2000000000;
 CREATE TABLE gtestx (x int, y int);
 INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
 SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
 DROP TABLE gtestx;
 
 -- test UPDATE/DELETE quals
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9a3bee93de..a9e15be55f 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2632,6 +2632,7 @@ SetOperation
 SetOperationStmt
 SetQuantifier
 SetToDefault
+SetVarNullingrels_context
 SetVarReturningType_context
 SetupWorkerPtrType
 ShDependObjectInfo
-- 
2.34.1

From 2f9bd9ec737227b1b2dc52a4800d006bfa228003 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Thu, 13 Feb 2025 11:28:57 +0800
Subject: [PATCH v2 1/1] fix expand virtual generated column Var node
 varnullingrels field

To expand the virtual generated column Var node,
we need to copy the fields of the original virtual generated column Var node,
including varnullingrels, varlevelsup, varreturningtype, and varattno,
to the newly expanded Var node.

ReplaceVarsFromTargetList_callback didn't taken care of varnullingrels,
this patch fix this issue.

discussion: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
---
 src/backend/rewrite/rewriteManip.c            | 62 +++++++++++++++++++
 src/include/rewrite/rewriteManip.h            |  3 +
 .../regress/expected/generated_virtual.out    | 45 ++++++++++++++
 src/test/regress/sql/generated_virtual.sql    | 11 ++++
 src/tools/pgindent/typedefs.list              |  1 +
 5 files changed, 122 insertions(+)

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index a115b217c91..69701ce6ecd 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -884,6 +884,64 @@ IncrementVarSublevelsUp_rtable(List *rtable, int delta_sublevels_up,
 					   QTW_EXAMINE_RTES_BEFORE);
 }
 
+/*
+ * SetVarNullingrels - adjust Var nodes for a specified varnullingrels.
+ *
+ * Find all Var nodes referring to the specified varno in the given
+ * expression and set their varnullingrels to the specified value.
+ */
+typedef struct
+{
+	int			sublevels_up;
+	int			varno;
+	Bitmapset *varnullingrels;
+} SetVarNullingrels_context;
+
+static bool
+SetVarNullingrels_walker(Node *node,
+						 SetVarNullingrels_context *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varlevelsup == context->sublevels_up &&
+			var->varno == context->varno)
+			var->varnullingrels = bms_union(context->varnullingrels,
+											var->varnullingrels);
+
+		return false;
+	}
+
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		context->sublevels_up++;
+		result = query_tree_walker((Query *) node, SetVarNullingrels_walker,
+								   context, 0);
+		context->sublevels_up--;
+		return result;
+	}
+	return expression_tree_walker(node, SetVarNullingrels_walker, context);
+}
+void
+SetVarNullingrels(Node *node, int sublevels_up, int varno, Bitmapset *varnullingrels)
+{
+	SetVarNullingrels_context context;
+
+	context.sublevels_up = sublevels_up;
+	context.varno = varno;
+	context.varnullingrels = varnullingrels;
+
+	/* Expect to start with an expression */
+	SetVarNullingrels_walker(node, &context);
+}
+
 /*
  * SetVarReturningType - adjust Var nodes for a specified varreturningtype.
  *
@@ -1832,6 +1890,10 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		if (var->varlevelsup > 0)
 			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
 
+		if (var->varnullingrels != NULL)
+			SetVarNullingrels((Node *) newnode, var->varlevelsup,
+							  var->varno,
+							  var->varnullingrels);
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 512823033b9..e869f651fc8 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -48,6 +48,9 @@ extern void ChangeVarNodes(Node *node, int rt_index, int new_index,
 						   int sublevels_up);
 extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 									int min_sublevels_up);
+extern void SetVarNullingrels(Node *node, int sublevels_up,
+							  int varno,
+							  Bitmapset *varnullingrels);
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 35638812be9..56e7e6fd6b0 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -181,6 +181,51 @@ SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
  22 | 2 | 2 | 4
 (2 rows)
 
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+   6
+   6
+   6
+(6 rows)
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+ x  
+----
+ 11
+ 22
+ 33
+(3 rows)
+
 DROP TABLE gtestx;
 -- test UPDATE/DELETE quals
 SELECT * FROM gtest1 ORDER BY a;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34870813910..d76439ca993 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -80,6 +80,17 @@ DELETE FROM gtest1 WHERE a = 2000000000;
 CREATE TABLE gtestx (x int, y int);
 INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
 SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 left JOIN gtest1 T ON true;
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+
 DROP TABLE gtestx;
 
 -- test UPDATE/DELETE quals
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b6c170ac249..6cb39ac76c5 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2633,6 +2633,7 @@ SetOperation
 SetOperationStmt
 SetQuantifier
 SetToDefault
+SetVarNullingrels_context
 SetVarReturningType_context
 SetupWorkerPtrType
 ShDependObjectInfo
-- 
2.34.1

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
new file mode 100644
index 7b1a8a0..041c152
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -712,6 +712,13 @@ subquery_planner(PlannerGlobal *glob, Qu
 	transform_MERGE_to_join(parse);
 
 	/*
+	 * Expand any virtual generated columns.  Note that this step does not
+	 * descend into subqueries; if we pull up any subqueries below, their
+	 * virtual generated columns are expanded just before pulling them up.
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root, parse);
+
+	/*
 	 * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
 	 * that we don't need so many special cases to deal with that situation.
 	 */
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
new file mode 100644
index 5d9225e..95ef3f4
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -4,6 +4,8 @@
  *	  Planner preprocessing for subqueries and join tree manipulation.
  *
  * NOTE: the intended sequence for invoking these operations is
+ *		transform_MERGE_to_join
+ *		expand_virtual_generated_columns
  *		replace_empty_jointree
  *		pull_up_sublinks
  *		preprocess_function_rtes
@@ -25,6 +27,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,8 +42,25 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
+
+
+typedef struct expand_generated_table_context
+{
+	int			num_attrs;		/* number of table columns */
+	List	   *tlist;			/* virtual generated column replacements */
+	Node	  **eg_cache;		/* cache for results with PHVs */
+} expand_generated_table_context;
 
+typedef struct expand_generated_context
+{
+	PlannerInfo *root;
+	Query	   *parse;			/* query being rewritten */
+	int			sublevels_up;	/* (current) nesting depth */
+	expand_generated_table_context *tbl_contexts;	/* per RTE of query */
+} expand_generated_context;
 
 typedef struct nullingrel_info
 {
@@ -87,6 +107,8 @@ typedef struct reduce_outer_joins_partia
 	Relids		unreduced_side; /* relids in its still-nullable side */
 } reduce_outer_joins_partial_state;
 
+static Node *expand_virtual_generated_columns_callback(Node *node,
+													   expand_generated_context *context);
 static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
 											   Relids *relids);
 static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
@@ -378,6 +400,227 @@ transform_MERGE_to_join(Query *parse)
 }
 
 /*
+ * Expand all virtual generated column references in a query.
+ *
+ * Note that this only processes virtual generated columns in relation RTEs
+ * in the query's rtable; it does not descend into subqueries.
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root, Query *parse)
+{
+	expand_generated_context egcontext;
+	int			rt_index;
+
+	egcontext.root = root;
+	egcontext.parse = parse;
+	egcontext.sublevels_up = 0;
+	egcontext.tbl_contexts = NULL;
+
+	/* Scan the range table for relations with virtual generated columns */
+	rt_index = 0;
+	foreach_node(RangeTblEntry, rte, parse->rtable)
+	{
+		Relation	rel;
+		int			num_attrs;
+		List	   *tlist;
+
+		++rt_index;
+
+		/* Only normal relations can have virtual generated columns */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		/*
+		 * Look for virtual generated columns.  We assume that previous code
+		 * already acquired a lock on the table, so we need no lock here.
+		 */
+		rel = table_open(rte->relid, NoLock);
+		num_attrs = RelationGetDescr(rel)->natts;
+		tlist = get_virtual_generated_columns(rel, rt_index);
+		table_close(rel, NoLock);
+
+		if (tlist)
+		{
+			expand_generated_table_context *tctx;
+
+			/*
+			 * Record details of this table's virtual generated columns. The
+			 * first time through, build the per-table context array.
+			 */
+			if (egcontext.tbl_contexts == NULL)
+				egcontext.tbl_contexts = palloc0(list_length(parse->rtable) *
+												 sizeof(expand_generated_table_context));
+
+			tctx = &egcontext.tbl_contexts[rt_index - 1];
+			tctx->num_attrs = num_attrs;
+			tctx->tlist = tlist;
+			/* PHV cache for each attr, plus wholerow (attrnum = 0) */
+			tctx->eg_cache = palloc0((num_attrs + 1) * sizeof(Node *));
+		}
+	}
+
+	/*
+	 * If any relations had virtual generated columns, perform the necessary
+	 * replacements.
+	 */
+	if (egcontext.tbl_contexts != NULL)
+		parse = query_tree_mutator(parse,
+								   expand_virtual_generated_columns_callback,
+								   &egcontext,
+								   0);
+
+	return parse;
+}
+
+static Node *
+expand_virtual_generated_columns_callback(Node *node,
+										  expand_generated_context *context)
+{
+	if (node == NULL)
+		return NULL;
+	else if (IsA(node, Var))
+	{
+		Query	   *parse = context->parse;
+		Var		   *var = (Var *) node;
+
+		/*
+		 * If the Var is from a relation with virtual generated columns, then
+		 * replace it with the appropriate expression, if necessary.
+		 */
+		if (var->varlevelsup == context->sublevels_up &&
+			var->varno > 0 &&
+			var->varno <= list_length(parse->rtable) &&
+			context->tbl_contexts[var->varno - 1].tlist)
+		{
+			expand_generated_table_context *tctx;
+			Node	   *newnode;
+
+			tctx = &context->tbl_contexts[var->varno - 1];
+
+			/*
+			 * If the Var has nonempty varnullingrels, the replacement
+			 * expression (if any) is wrapped in a PlaceHolderVar, unless it
+			 * is simply another Var.  These are cached to avoid generating
+			 * identical PHVs with different IDs, which would lead to
+			 * duplicate evaluations at runtime.  See similar code in
+			 * pullup_replace_vars_callback().
+			 *
+			 * The cached items have phlevelsup = 0 and phnullingrels = NULL,
+			 * so we need to copy and adjust them.
+			 */
+			if (var->varnullingrels != NULL &&
+				var->varattno >= InvalidAttrNumber &&
+				var->varattno <= tctx->num_attrs &&
+				tctx->eg_cache[var->varattno] != NULL)
+			{
+				/* Copy the cached item and adjust its varlevelsup */
+				newnode = copyObject(tctx->eg_cache[var->varattno]);
+				if (var->varlevelsup > 0)
+					IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
+			}
+			else
+			{
+				/*
+				 * Generate the replacement expression. This takes care of
+				 * expanding wholerow references, as well as adjusting
+				 * varlevelsup and varreturningtype.
+				 */
+				newnode = ReplaceVarFromTargetList(var,
+												   rt_fetch(var->varno,
+															parse->rtable),
+												   tctx->tlist,
+												   parse->resultRelation,
+												   REPLACEVARS_CHANGE_VARNO,
+												   var->varno);
+
+				/* Insert PlaceHolderVar if needed */
+				if (var->varnullingrels != NULL && !IsA(newnode, Var))
+				{
+					/* XXX: Consider not wrapping every expression */
+					newnode = (Node *)
+						make_placeholder_expr(context->root,
+											  (Expr *) newnode,
+											  bms_make_singleton(var->varno));
+
+					/*
+					 * Adjust the PlaceHolderVar's phlevelsup (the wrapped
+					 * expression itself is already correct at this point).
+					 */
+					((PlaceHolderVar *) newnode)->phlevelsup = var->varlevelsup;
+
+					/*
+					 * Cache it if possible (ie, if the attno is in range,
+					 * which it probably always should be), ensuring that the
+					 * cached item has phlevelsup = 0.
+					 */
+					if (var->varattno >= InvalidAttrNumber &&
+						var->varattno <= tctx->num_attrs)
+					{
+						Node	   *cachenode = copyObject(newnode);
+
+						if (var->varlevelsup > 0)
+							IncrementVarSublevelsUp(cachenode,
+													-((int) var->varlevelsup),
+													0);
+
+						tctx->eg_cache[var->varattno] = cachenode;
+					}
+				}
+			}
+
+			/* Propagate any varnullingrels into the replacement expression */
+			if (var->varnullingrels != NULL)
+			{
+				if (IsA(newnode, Var))
+				{
+					Var		   *newvar = (Var *) newnode;
+
+					Assert(newvar->varlevelsup == var->varlevelsup);
+					newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
+															 var->varnullingrels);
+				}
+				else if (IsA(newnode, PlaceHolderVar))
+				{
+					PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
+
+					Assert(newphv->phlevelsup == var->varlevelsup);
+					newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
+															var->varnullingrels);
+				}
+				else
+				{
+					/*
+					 * Currently, the code above wraps all non-Var expressions
+					 * in PlaceHolderVars, so we should never see anything
+					 * else here.  If that changes, this will need code
+					 * similar to that in pullup_replace_vars_callback().
+					 */
+					elog(ERROR, "unexpected expression for virtual generated column");
+				}
+			}
+
+			return newnode;
+		}
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *newnode;
+
+		context->sublevels_up++;
+		newnode = query_tree_mutator((Query *) node,
+									 expand_virtual_generated_columns_callback,
+									 context,
+									 0);
+		context->sublevels_up--;
+
+		return (Node *) newnode;
+	}
+	return expression_tree_mutator(node,
+								   expand_virtual_generated_columns_callback,
+								   context);
+}
+
+/*
  * replace_empty_jointree
  *		If the Query's jointree is empty, replace it with a dummy RTE_RESULT
  *		relation.
@@ -1179,6 +1422,13 @@ pull_up_simple_subquery(PlannerInfo *roo
 	Assert(subquery->cteList == NIL);
 
 	/*
+	 * Expand any virtual generated columns in the subquery, before we pull it
+	 * up (this has already been done for the parent query).
+	 */
+	subquery = subroot->parse = expand_virtual_generated_columns(subroot,
+																 subquery);
+
+	/*
 	 * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
 	 * that we don't need so many special cases to deal with that situation.
 	 */
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
new file mode 100644
index e996bdc..ecc695f
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -96,8 +96,6 @@ static List *matchLocks(CmdType event, R
 						int varno, Query *parsetree, bool *hasUpdate);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
 static Bitmapset *adjust_view_column_set(Bitmapset *cols, List *targetlist);
-static Node *expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
-											   RangeTblEntry *rte, int result_relation);
 
 
 /*
@@ -2190,10 +2188,6 @@ fireRIRrules(Query *parsetree, List *act
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
-	 *
-	 * Finally, we expand any virtual generated columns.  We do this after
-	 * each table's RLS policies are applied because the RLS policies might
-	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2207,11 +2201,10 @@ fireRIRrules(Query *parsetree, List *act
 
 		++rt_index;
 
-		/*
-		 * Only normal relations can have RLS policies or virtual generated
-		 * columns.
-		 */
-		if (rte->rtekind != RTE_RELATION)
+		/* Only normal relations can have RLS policies */
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2293,6 @@ fireRIRrules(Query *parsetree, List *act
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
@@ -4425,31 +4408,20 @@ RewriteQuery(Query *parsetree, List *rew
 
 
 /*
- * Expand virtual generated columns
- *
- * If the table contains virtual generated columns, build a target list
- * containing the expanded expressions and use ReplaceVarsFromTargetList() to
- * do the replacements.
- *
- * Vars matching rt_index at the current query level are replaced by the
- * virtual generated column expressions from rel, if there are any.
+ * Get the virtual generated columns of a relation.
  *
- * The caller must also provide rte, the RTE describing the target relation,
- * in order to handle any whole-row Vars referencing the target, and
- * result_relation, the index of the result relation, if this is part of an
- * INSERT/UPDATE/DELETE/MERGE query.
+ * The returned list is in the form of a targetlist (of TargetEntry nodes)
+ * suitable for use by ReplaceVarFromTargetList/ReplaceVarsFromTargetList to
+ * expand references to virtual generated columns.
  */
-static Node *
-expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
-								  RangeTblEntry *rte, int result_relation)
+List *
+get_virtual_generated_columns(Relation rel, int rt_index)
 {
-	TupleDesc	tupdesc;
+	TupleDesc	tupdesc = RelationGetDescr(rel);
+	List	   *tlist = NIL;
 
-	tupdesc = RelationGetDescr(rel);
 	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
-		List	   *tlist = NIL;
-
 		for (int i = 0; i < tupdesc->natts; i++)
 		{
 			Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
@@ -4491,14 +4463,8 @@ expand_generated_columns_internal(Node *
 		}
 
 		Assert(list_length(tlist) > 0);
-
-		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist,
-										 result_relation,
-										 REPLACEVARS_CHANGE_VARNO, rt_index,
-										 NULL);
 	}
-
-	return node;
+	return tlist;
 }
 
 /*
@@ -4515,6 +4481,7 @@ expand_generated_columns_in_expr(Node *n
 	if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
 	{
 		RangeTblEntry *rte;
+		List	   *tlist;
 
 		rte = makeNode(RangeTblEntry);
 		/* eref needs to be set, but the actual name doesn't matter */
@@ -4522,7 +4489,11 @@ expand_generated_columns_in_expr(Node *n
 		rte->rtekind = RTE_RELATION;
 		rte->relid = RelationGetRelid(rel);
 
-		node = expand_generated_columns_internal(node, rel, rt_index, rte, 0);
+		tlist = get_virtual_generated_columns(rel, rt_index);
+
+		node = ReplaceVarsFromTargetList(node, rt_index, 0, rte, tlist, 0,
+										 REPLACEVARS_CHANGE_VARNO, rt_index,
+										 NULL);
 	}
 
 	return node;
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
new file mode 100644
index a115b21..cc268a5
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1736,6 +1736,23 @@ ReplaceVarsFromTargetList_callback(Var *
 								   replace_rte_variables_context *context)
 {
 	ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
+
+	return ReplaceVarFromTargetList(var,
+									rcon->target_rte,
+									rcon->targetlist,
+									rcon->result_relation,
+									rcon->nomatch_option,
+									rcon->nomatch_varno);
+}
+
+Node *
+ReplaceVarFromTargetList(Var *var,
+						 RangeTblEntry *target_rte,
+						 List *targetlist,
+						 int result_relation,
+						 ReplaceVarsNoMatchOption nomatch_option,
+						 int nomatch_varno)
+{
 	TargetEntry *tle;
 
 	if (var->varattno == InvalidAttrNumber)
@@ -1744,6 +1761,7 @@ ReplaceVarsFromTargetList_callback(Var *
 		RowExpr    *rowexpr;
 		List	   *colnames;
 		List	   *fields;
+		ListCell   *lc;
 
 		/*
 		 * If generating an expansion for a var of a named rowtype (ie, this
@@ -1755,15 +1773,27 @@ ReplaceVarsFromTargetList_callback(Var *
 		 * The varreturningtype is copied onto each individual field Var, so
 		 * that it is handled correctly when we recurse.
 		 */
-		expandRTE(rcon->target_rte,
+		expandRTE(target_rte,
 				  var->varno, var->varlevelsup, var->varreturningtype,
 				  var->location, (var->vartype != RECORDOID),
 				  &colnames, &fields);
 		/* Adjust the generated per-field Vars... */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
 		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
+		rowexpr->args = NIL;
+		foreach(lc, fields)
+		{
+			Node	   *field = lfirst(lc);
+
+			if (field != NULL)
+				field = ReplaceVarFromTargetList((Var *) field,
+												 target_rte,
+												 targetlist,
+												 result_relation,
+												 nomatch_option,
+												 nomatch_varno);
+
+			rowexpr->args = lappend(rowexpr->args, field);
+		}
 		rowexpr->row_typeid = var->vartype;
 		rowexpr->row_format = COERCE_IMPLICIT_CAST;
 		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
@@ -1785,12 +1815,12 @@ ReplaceVarsFromTargetList_callback(Var *
 	}
 
 	/* Normal case referencing one targetlist element */
-	tle = get_tle_by_resno(rcon->targetlist, var->varattno);
+	tle = get_tle_by_resno(targetlist, var->varattno);
 
 	if (tle == NULL || tle->resjunk)
 	{
 		/* Failed to find column in targetlist */
-		switch (rcon->nomatch_option)
+		switch (nomatch_option)
 		{
 			case REPLACEVARS_REPORT_ERROR:
 				/* fall through, throw error below */
@@ -1798,7 +1828,7 @@ ReplaceVarsFromTargetList_callback(Var *
 
 			case REPLACEVARS_CHANGE_VARNO:
 				var = copyObject(var);
-				var->varno = rcon->nomatch_varno;
+				var->varno = nomatch_varno;
 				/* we leave the syntactic referent alone */
 				return (Node *) var;
 
@@ -1854,15 +1884,15 @@ ReplaceVarsFromTargetList_callback(Var *
 			 * Copy varreturningtype onto any Vars in the tlist item that
 			 * refer to result_relation (which had better be non-zero).
 			 */
-			if (rcon->result_relation == 0)
+			if (result_relation == 0)
 				elog(ERROR, "variable returning old/new found outside RETURNING list");
 
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
+			SetVarReturningType((Node *) newnode, result_relation,
 								var->varlevelsup, var->varreturningtype);
 
 			/* Wrap it in a ReturningExpr, if needed, per comments above */
 			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varno != result_relation ||
 				((Var *) newnode)->varlevelsup != var->varlevelsup)
 			{
 				ReturningExpr *rexpr = makeNode(ReturningExpr);
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
new file mode 100644
index 0ae57ec..9c93643
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -22,6 +22,7 @@
  * prototypes for prepjointree.c
  */
 extern void transform_MERGE_to_join(Query *parse);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root, Query *parse);
 extern void replace_empty_jointree(Query *parse);
 extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
new file mode 100644
index 88fe13c..21876cf
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -38,6 +38,7 @@ extern void error_view_not_updatable(Rel
 									 List *mergeActionList,
 									 const char *detail);
 
+extern List *get_virtual_generated_columns(Relation rel, int rt_index);
 extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
 
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
new file mode 100644
index 5128230..afce743
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -85,6 +85,13 @@ extern Node *map_variable_attnos(Node *n
 								 const struct AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
+extern Node *ReplaceVarFromTargetList(Var *var,
+									  RangeTblEntry *target_rte,
+									  List *targetlist,
+									  int result_relation,
+									  ReplaceVarsNoMatchOption nomatch_option,
+									  int nomatch_varno);
+
 extern Node *ReplaceVarsFromTargetList(Node *node,
 									   int target_varno, int sublevels_up,
 									   RangeTblEntry *target_rte,
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
new file mode 100644
index b6c170a..4d0fcab
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -3484,6 +3484,8 @@ eval_const_expressions_context
 exec_thread_arg
 execution_state
 exit_function
+expand_generated_context
+expand_generated_table_context
 explain_get_index_name_hook_type
 f_smgr
 fasthash_state

From 69d4749613127323bd01fcad41c8154f6744a52f Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Mon, 17 Feb 2025 14:37:17 +0800
Subject: [PATCH] fix expand virtual generated column Var node varnullingrels
 field

To expand the virtual generated column Var node,
we need to copy the fields of the original virtual generated column Var node,
including varnullingrels, varlevelsup, varreturningtype, and varattno,
to the newly expanded Var node.

ReplaceVarsFromTargetList_callback didn't taken care of varnullingrels,
this patch fix this issue.

discussion: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
---
 src/backend/optimizer/plan/planner.c          |   5 +
 src/backend/optimizer/prep/prepjointree.c     | 122 ++++++++++++++++++
 src/backend/rewrite/rewriteHandler.c          |  39 ++++--
 src/backend/rewrite/rewriteManip.c            | 120 +++++++++++++++++
 src/include/optimizer/prep.h                  |   1 +
 src/include/rewrite/rewriteHandler.h          |   1 +
 src/include/rewrite/rewriteManip.h            |   4 +
 .../regress/expected/generated_virtual.out    |  59 +++++++++
 src/test/regress/sql/generated_virtual.sql    |  17 +++
 src/tools/pgindent/typedefs.list              |   1 +
 10 files changed, 359 insertions(+), 10 deletions(-)

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 7b1a8a0a9f1..8f0be3dfadc 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -57,6 +57,7 @@
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
 #include "partitioning/partdesc.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
@@ -706,6 +707,10 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 	if (parse->cteList)
 		SS_process_ctes(root);
 
+	parse = (Query *) preprocess_nullable_generated_cols(root, (Node *) root->parse);
+	parse = (Query *) expand_generated_columns((Node *) parse);
+	root->parse = parse;
+
 	/*
 	 * If it's a MERGE command, transform the joinlist as appropriate.
 	 */
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5d9225e9909..8224a53da47 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -25,6 +25,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -40,6 +41,7 @@
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -68,6 +70,14 @@ typedef struct pullup_replace_vars_context
 	Node	  **rv_cache;		/* cache for results with PHVs */
 } pullup_replace_vars_context;
 
+typedef struct replace_varsnulling_context
+{
+	PlannerInfo *root;
+	RangeTblEntry *target_rte;	/* RTE of subquery */
+	Bitmapset  *gen_varattno;
+	int			target_varno;	/* RTE index to search for */
+	int			sublevels_up;	/* (current) nesting depth */
+} replace_varsnulling_context;
 typedef struct reduce_outer_joins_pass1_state
 {
 	Relids		relids;			/* base relids within this subtree */
@@ -160,6 +170,118 @@ static void get_nullingrels_recurse(Node *jtnode, Relids upper_nullingrels,
 									nullingrel_info *info);
 
 
+static Node *
+replace_varnulling_variables_mutator(Node *node,
+									 replace_varsnulling_context *context)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varno == context->target_varno &&
+			var->varlevelsup == context->sublevels_up &&
+			bms_is_member(var->varattno, context->gen_varattno) &&
+			var->varnullingrels != NULL)
+		{
+			Node	   *newnode;
+			PlaceHolderVar *newphv;
+			newnode = (Node *) copyObject(var);
+
+			newnode = (Node *)
+				make_placeholder_expr(context->root,
+									 (Expr *) newnode,
+									 bms_make_singleton(context->target_varno));
+
+			newphv = (PlaceHolderVar *) newnode;
+			newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
+														var->varnullingrels);
+			newphv->phlevelsup = var->varlevelsup;
+			return newnode;
+		}
+	}
+	else if (IsA(node, Query))
+	{
+		Query	   *newnode;
+		context->sublevels_up++;
+		newnode = query_tree_mutator((Query *) node,
+									 replace_varnulling_variables_mutator,
+									 context,
+									 0);
+		context->sublevels_up--;
+		return (Node *) newnode;
+	}
+	return expression_tree_mutator(node, replace_varnulling_variables_mutator, context);
+}
+
+static Node *
+replace_varsnulling(Node *node, replace_varsnulling_context *context)
+{
+	Node	   *result;
+
+	result = query_or_expression_tree_mutator(node,
+											  replace_varnulling_variables_mutator,
+											  context,
+											  0);
+	return result;
+}
+
+Node *
+preprocess_nullable_generated_cols(PlannerInfo *root, Node *node)
+{
+	int			rt_index = 0;
+	Query	   *parse = (Query *) node;
+
+	foreach_node(RangeTblEntry, rte, parse->rtable)
+	{
+		++rt_index;
+
+		if (rte->rtekind == RTE_RELATION)
+		{
+			Relation	rel;
+			TupleDesc	tupdesc;
+
+			rel = table_open(rte->relid, NoLock);
+			tupdesc = RelationGetDescr(rel);
+
+			if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+			{
+				int			i;
+				Bitmapset  *generated_cols	= NULL;
+
+				for (i = 1; i <= tupdesc->natts; i++)
+				{
+					Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
+
+					/* Ignore dropped attributes. */
+					if (attr->attisdropped)
+						continue;
+
+					if (attr->attgenerated != ATTRIBUTE_GENERATED_VIRTUAL)
+						continue;
+
+					if (attno_contain_varnullingrel((Node *) parse->targetList, rt_index, attr->attnum))
+						generated_cols = bms_add_member(generated_cols, attr->attnum);
+				}
+				if (generated_cols != NULL)
+				{
+					replace_varsnulling_context rvcontext;
+					rvcontext.root = root;
+					rvcontext.target_rte = rte;
+					rvcontext.gen_varattno = generated_cols;
+					rvcontext.target_varno = rt_index;
+					rvcontext.sublevels_up = 0;
+
+					parse->targetList = (List *) replace_varsnulling((Node *) parse->targetList, &rvcontext);
+				}
+			}
+			table_close(rel, NoLock);
+		}
+	}
+	return (Node *)parse;
+}
+
 /*
  * transform_MERGE_to_join
  *		Replace a MERGE's jointree to also include the target relation.
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e996bdc0d21..2ab9566e1a0 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2300,16 +2300,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
@@ -4501,6 +4491,35 @@ expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
 	return node;
 }
 
+Node *
+expand_generated_columns(Node *node)
+{
+	int			rt_index = 0;
+	Query *parse = (Query *) node;
+	foreach_node(RangeTblEntry, rte, parse->rtable)
+	{
+		Relation	rel;
+
+		++rt_index;
+		if (rte->rtekind == RTE_SUBQUERY)
+		{
+			rte->subquery = (Query *)
+				expand_generated_columns((Node *) rte->subquery);
+		}
+
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+		parse = (Query *)
+			expand_generated_columns_internal((Node *) parse,
+											   rel, rt_index, rte,
+											   parse->resultRelation);
+		table_close(rel, NoLock);
+	}
+	return (Node *) parse;
+}
+
 /*
  * Expand virtual generated columns in an expression
  *
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index a115b217c91..d1f2e00b3a3 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -30,6 +30,13 @@ typedef struct
 	int			sublevels_up;
 } contain_aggs_of_level_context;
 
+typedef struct
+{
+	int			varno;
+	int			sublevels_up;
+	int			varattno;
+} attno_varnullingrel_context;
+
 typedef struct
 {
 	int			agg_location;
@@ -884,6 +891,64 @@ IncrementVarSublevelsUp_rtable(List *rtable, int delta_sublevels_up,
 					   QTW_EXAMINE_RTES_BEFORE);
 }
 
+/*
+ * SetVarNullingrels - adjust Var nodes for a specified varnullingrels.
+ *
+ * Find all Var nodes referring to the specified varno in the given
+ * expression and set their varnullingrels to the specified value.
+ */
+typedef struct
+{
+	int			sublevels_up;
+	int			varno;
+	Bitmapset *varnullingrels;
+} SetVarNullingrels_context;
+
+static bool
+SetVarNullingrels_walker(Node *node,
+						 SetVarNullingrels_context *context)
+{
+	if (node == NULL)
+		return false;
+
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varlevelsup == context->sublevels_up &&
+			var->varno == context->varno)
+			var->varnullingrels = bms_union(context->varnullingrels,
+											var->varnullingrels);
+
+		return false;
+	}
+
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		context->sublevels_up++;
+		result = query_tree_walker((Query *) node, SetVarNullingrels_walker,
+								   context, 0);
+		context->sublevels_up--;
+		return result;
+	}
+	return expression_tree_walker(node, SetVarNullingrels_walker, context);
+}
+void
+SetVarNullingrels(Node *node, int sublevels_up, int varno, Bitmapset *varnullingrels)
+{
+	SetVarNullingrels_context context;
+
+	context.sublevels_up = sublevels_up;
+	context.varno = varno;
+	context.varnullingrels = varnullingrels;
+
+	/* Expect to start with an expression */
+	SetVarNullingrels_walker(node, &context);
+}
+
 /*
  * SetVarReturningType - adjust Var nodes for a specified varreturningtype.
  *
@@ -1199,6 +1264,57 @@ AddInvertedQual(Query *parsetree, Node *qual)
 }
 
 
+static bool
+attno_contain_varnullingrel_walker(Node *node,
+								   attno_varnullingrel_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Var))
+	{
+		Var		   *var = (Var *) node;
+
+		if (var->varno == context->varno
+			&& var->varattno == context->varattno
+			&& var->varlevelsup == context->sublevels_up)
+		{
+			if (var->varnullingrels != NULL)
+				return true;
+		}
+		return false;
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		context->sublevels_up++;
+		result = query_tree_walker((Query *) node,
+								   attno_contain_varnullingrel_walker,
+								   context, 0);
+		context->sublevels_up--;
+
+		return result;
+	}
+	return expression_tree_walker(node, attno_contain_varnullingrel_walker,
+								  context);
+}
+
+bool
+attno_contain_varnullingrel(Node *node, int varno, int varattno)
+{
+	attno_varnullingrel_context context;
+
+	context.varno = varno;
+	context.sublevels_up = 0;
+	context.varattno = varattno;
+
+	return query_or_expression_tree_walker(node,
+										   attno_contain_varnullingrel_walker,
+										   &context,
+										   0);
+}
+
 /*
  * add_nulling_relids() finds Vars and PlaceHolderVars that belong to any
  * of the target_relids, and adds added_relids to their varnullingrels
@@ -1832,6 +1948,10 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		if (var->varlevelsup > 0)
 			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
 
+		if (var->varnullingrels != NULL)
+			SetVarNullingrels((Node *) newnode, var->varlevelsup,
+							  var->varno,
+							  var->varnullingrels);
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 0ae57ec24a4..e63af1f2a85 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -33,6 +33,7 @@ extern Relids get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
 									 bool include_inner_joins);
 extern Relids get_relids_for_join(Query *query, int joinrelid);
 
+extern Node *preprocess_nullable_generated_cols(PlannerInfo *root, Node *node);
 /*
  * prototypes for preptlist.c
  */
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 88fe13c5f4f..dff5746c0d6 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -39,5 +39,6 @@ extern void error_view_not_updatable(Relation view,
 									 const char *detail);
 
 extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+extern Node *expand_generated_columns(Node *node);
 
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 512823033b9..c16d18345ab 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -48,6 +48,9 @@ extern void ChangeVarNodes(Node *node, int rt_index, int new_index,
 						   int sublevels_up);
 extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 									int min_sublevels_up);
+extern void SetVarNullingrels(Node *node, int sublevels_up,
+							  int varno,
+							  Bitmapset *varnullingrels);
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
@@ -60,6 +63,7 @@ extern void AddQual(Query *parsetree, Node *qual);
 extern void AddInvertedQual(Query *parsetree, Node *qual);
 
 extern bool contain_aggs_of_level(Node *node, int levelsup);
+extern bool attno_contain_varnullingrel(Node *node, int varno, int varattno);
 extern int	locate_agg_of_level(Node *node, int levelsup);
 extern bool contain_windowfuncs(Node *node);
 extern int	locate_windowfunc(Node *node);
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 35638812be9..babf16db8ba 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -19,6 +19,14 @@ SELECT table_name, column_name, dependent_column FROM information_schema.column_
  gtest1     | a           | b
 (1 row)
 
+--left join generated expression expandsion varnulling field is sane
+insert into gtest0 values(1);
+select t2.b is null as true from gtest0 t1 left join gtest0 t2 on false;
+ true 
+------
+ t
+(1 row)
+
 \d gtest1
                 Table "generated_virtual_tests.gtest1"
  Column |  Type   | Collation | Nullable |           Default           
@@ -166,6 +174,12 @@ SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
  2 | 4
 (1 row)
 
+SELECT t2.b is null as true FROM gtest1 t1 LEFT JOIN gtest1 t2 ON false WHERE t1.b = 4;
+ true 
+------
+ t
+(1 row)
+
 -- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
@@ -181,6 +195,51 @@ SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
  22 | 2 | 2 | 4
 (2 rows)
 
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 LEFT JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+  12
+  12
+  12
+(6 rows)
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+ sum 
+-----
+   6
+   6
+   6
+   6
+   6
+   6
+(6 rows)
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+ x  
+----
+ 11
+ 22
+ 33
+(3 rows)
+
 DROP TABLE gtestx;
 -- test UPDATE/DELETE quals
 SELECT * FROM gtest1 ORDER BY a;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34870813910..aaf5661ea3d 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -12,6 +12,10 @@ SELECT table_name, column_name, column_default, is_nullable, is_generated, gener
 
 SELECT table_name, column_name, dependent_column FROM information_schema.column_column_usage WHERE table_schema = 'generated_virtual_tests' ORDER BY 1, 2, 3;
 
+--left join generated expression expandsion varnulling field is sane
+insert into gtest0 values(1);
+select t2.b is null as true from gtest0 t1 left join gtest0 t2 on false;
+
 \d gtest1
 
 -- duplicate generated
@@ -71,6 +75,8 @@ SELECT * FROM gtest1 ORDER BY a;
 SELECT a, b, b * 2 AS b2 FROM gtest1 ORDER BY a;
 SELECT a, b FROM gtest1 WHERE b = 4 ORDER BY a;
 
+SELECT t2.b is null as true FROM gtest1 t1 LEFT JOIN gtest1 t2 ON false WHERE t1.b = 4;
+
 -- test that overflow error happens on read
 INSERT INTO gtest1 VALUES (2000000000);
 SELECT * FROM gtest1;
@@ -80,6 +86,17 @@ DELETE FROM gtest1 WHERE a = 2000000000;
 CREATE TABLE gtestx (x int, y int);
 INSERT INTO gtestx VALUES (11, 1), (22, 2), (33, 3);
 SELECT * FROM gtestx, gtest1 WHERE gtestx.y = gtest1.a;
+--bug: https://postgr.es/m/75eb1a6f-d59f-42e6-8a78-124ee808cda7@gmail.com
+SELECT SUM(t.b) OVER (PARTITION BY t.a) FROM gtestx AS t1 LEFT JOIN gtest1 T ON true;
+--this query result should be same as as the above
+SELECT SUM((select t.b from ((select t.b from gtest1 as t order by t.b limit 1)))) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT SUM((select t.b from gtest1 as t order by t.b limit 1)) OVER (PARTITION BY t.a)
+FROM gtestx AS t1 left JOIN gtest1 T ON true;
+
+SELECT t.x FROM gtestx t LEFT JOIN gtest1 vt on t.x = vt.a WHERE coalesce(vt.b, 1) = 1 OR t.x IS NULL;
+
 DROP TABLE gtestx;
 
 -- test UPDATE/DELETE quals
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index b6c170ac249..6cb39ac76c5 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2633,6 +2633,7 @@ SetOperation
 SetOperationStmt
 SetQuantifier
 SetToDefault
+SetVarNullingrels_context
 SetVarReturningType_context
 SetupWorkerPtrType
 ShDependObjectInfo
-- 
2.34.1

From 96c822e322652a29d0eab791565c54c9d0cd73af Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Wed, 12 Feb 2025 17:55:35 +0900
Subject: [PATCH v2] Expand virtual generated columns in planner

---
 src/backend/optimizer/plan/planner.c      |   6 +
 src/backend/optimizer/prep/prepjointree.c | 180 ++++++++++++++++++++++
 src/backend/rewrite/rewriteHandler.c      |  14 +-
 src/backend/rewrite/rewriteManip.c        |   2 +-
 src/include/optimizer/prep.h              |   1 +
 src/include/rewrite/rewriteManip.h        |   2 +
 6 files changed, 193 insertions(+), 12 deletions(-)

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 7b1a8a0a9f..c80108a06c 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -749,6 +749,12 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 	if (parse->setOperations)
 		flatten_simple_union_all(root);
 
+	/*
+	 * Expand virtual generated columns.
+	 * XXX more comments
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root);
+
 	/*
 	 * Survey the rangetable to see what kinds of entries are present.  We can
 	 * skip some later processing if relevant SQL features are not used; for
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5d9225e990..99ef55f7ac 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -9,6 +9,7 @@
  *		preprocess_function_rtes
  *		pull_up_subqueries
  *		flatten_simple_union_all
+ *		expand_virtual_generated_columns
  *		do expression preprocessing (including flattening JOIN alias vars)
  *		reduce_outer_joins
  *		remove_useless_result_rtes
@@ -25,6 +26,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,7 +41,9 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -57,6 +61,7 @@ typedef struct pullup_replace_vars_context
 {
 	PlannerInfo *root;
 	List	   *targetlist;		/* tlist of subquery being pulled up */
+	int         result_relation;	/* the index of the result relation */
 	RangeTblEntry *target_rte;	/* RTE of subquery */
 	Relids		relids;			/* relids within subquery, as numbered after
 								 * pullup (set only if target_rte->lateral) */
@@ -1273,6 +1278,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	rvcontext.root = root;
 	rvcontext.targetlist = subquery->targetList;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	if (rte->lateral)
 	{
@@ -1833,6 +1839,7 @@ pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
 	}
 	rvcontext.root = root;
 	rvcontext.targetlist = tlist;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	rvcontext.relids = NULL;	/* can't be any lateral references here */
 	rvcontext.nullinfo = NULL;
@@ -1992,6 +1999,7 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode,
 													  1,	/* resno */
 													  NULL, /* resname */
 													  false));	/* resjunk */
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 
 	/*
@@ -2499,6 +2507,10 @@ pullup_replace_vars_callback(Var *var,
 	 */
 	need_phv = (var->varnullingrels != NULL) || rcon->wrap_non_vars;
 
+	/* System columns are not replaced. */
+	if (varattno < InvalidAttrNumber)
+		return (Node *) copyObject(var);
+
 	/*
 	 * If PlaceHolderVars are needed, we cache the modified expressions in
 	 * rcon->rv_cache[].  This is not in hopes of any material speed gain
@@ -2559,6 +2571,22 @@ pullup_replace_vars_callback(Var *var,
 		rowexpr->location = var->location;
 		newnode = (Node *) rowexpr;
 
+		/*
+		 * Handle any OLD/NEW RETURNING list Vars
+		 *
+		 * XXX comments about wrapping it into ReturningExpr
+		 */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+			rexpr->retlevelsup = var->varlevelsup;
+			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+			rexpr->retexpr = (Expr *) rowexpr;
+
+			newnode = (Node *) rexpr;
+		}
+
 		/*
 		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
 		 * PlaceHolderVar around the whole RowExpr, rather than putting one
@@ -2588,6 +2616,37 @@ pullup_replace_vars_callback(Var *var,
 		/* Make a copy of the tlist item to return */
 		newnode = (Node *) copyObject(tle->expr);
 
+		/*
+		 * Handle any OLD/NEW RETURNING list Vars
+		 *
+		 * XXX comments about wrapping it into ReturningExpr
+		 */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			/*
+			 * Copy varreturningtype onto any Vars in the tlist item that
+			 * refer to result_relation (which had better be non-zero).
+			 */
+			if (rcon->result_relation == 0)
+				elog(ERROR, "variable returning old/new found outside RETURNING list");
+
+			SetVarReturningType((Node *) newnode, rcon->result_relation,
+								var->varlevelsup, var->varreturningtype);
+
+			if (!IsA(newnode, Var) ||
+				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varlevelsup != var->varlevelsup)
+			{
+				ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+				rexpr->retlevelsup = var->varlevelsup;
+				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+				rexpr->retexpr = (Expr *) newnode;
+
+				newnode = (Node *) rexpr;
+			}
+		}
+
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
@@ -2947,6 +3006,127 @@ flatten_simple_union_all(PlannerInfo *root)
 }
 
 
+/*
+ * expand_virtual_generated_columns
+ *		Expand all virtual generated column references in a query.
+ *
+ * XXX more comments
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			rt_index;
+	ListCell   *lc;
+
+	rt_index = 0;
+	foreach(lc, parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+		TupleDesc	tupdesc;
+
+		++rt_index;
+
+		/*
+		 * Only normal relations can have virtual generated columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		tupdesc = RelationGetDescr(rel);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			List	   *tlist = NIL;
+			pullup_replace_vars_context rvcontext;
+
+			for (int i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+				int				attnum = i + 1;
+				TargetEntry	   *te;
+
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				{
+					Node	   *defexpr;
+					Oid			attcollid;
+
+					defexpr = build_column_default(rel, attnum);
+					if (defexpr == NULL)
+						elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+							 attnum, RelationGetRelationName(rel));
+
+					/*
+					 * If the column definition has a collation and it is
+					 * different from the collation of the generation expression,
+					 * put a COLLATE clause around the expression.
+					 */
+					attcollid = attr->attcollation;
+					if (attcollid && attcollid != exprCollation(defexpr))
+					{
+						CollateExpr *ce = makeNode(CollateExpr);
+
+						ce->arg = (Expr *) defexpr;
+						ce->collOid = attcollid;
+						ce->location = -1;
+
+						defexpr = (Node *) ce;
+					}
+
+					ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+					te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+				else
+				{
+					Var		   *var;
+
+					var = makeVar(rt_index,
+								  attnum,
+								  attr->atttypid,
+								  attr->atttypmod,
+								  attr->attcollation,
+								  0);
+					te = makeTargetEntry((Expr *) var, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+			}
+
+			Assert(list_length(tlist) > 0);
+
+			rvcontext.root = root;
+			rvcontext.targetlist = tlist;
+			rvcontext.result_relation = parse->resultRelation;
+			rvcontext.target_rte = rte;
+			rvcontext.relids = NULL;
+			rvcontext.nullinfo = NULL;
+			rvcontext.outer_hasSubLinks = NULL;
+			rvcontext.varno = rt_index;
+			rvcontext.wrap_non_vars = false;
+			rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
+										 sizeof(Node *));
+			/*
+			 * If the query uses grouping sets, we need a PlaceHolderVar for
+			 * anything that's not a simple Var.  This ensures that expressions
+			 * retain their separate identity so that they will match grouping
+			 * set columns when appropriate.
+			 */
+			if (parse->groupingSets)
+				rvcontext.wrap_non_vars = true;
+
+			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
+		}
+
+		table_close(rel, NoLock);
+	}
+
+	return parse;
+}
+
+
 /*
  * reduce_outer_joins
  *		Attempt to reduce outer joins to plain inner joins.
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e996bdc0d2..0b1fcb3758 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2211,7 +2211,9 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		 * Only normal relations can have RLS policies or virtual generated
 		 * columns.
 		 */
-		if (rte->rtekind != RTE_RELATION)
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2302,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 9433548d27..6994b8c542 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1010,7 +1010,7 @@ SetVarReturningType_walker(Node *node, SetVarReturningType_context *context)
 	return expression_tree_walker(node, SetVarReturningType_walker, context);
 }
 
-static void
+void
 SetVarReturningType(Node *node, int result_relation, int sublevels_up,
 					VarReturningType returning_type)
 {
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 0ae57ec24a..6bc75ac9f3 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -27,6 +27,7 @@ extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
 extern void pull_up_subqueries(PlannerInfo *root);
 extern void flatten_simple_union_all(PlannerInfo *root);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root);
 extern void reduce_outer_joins(PlannerInfo *root);
 extern void remove_useless_result_rtes(PlannerInfo *root);
 extern Relids get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 5ec475c63e..2f09657ab2 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -97,5 +97,7 @@ extern Node *ReplaceVarsFromTargetList(Node *node,
 									   ReplaceVarsNoMatchOption nomatch_option,
 									   int nomatch_varno,
 									   bool *outer_hasSubLinks);
+extern void SetVarReturningType(Node *node, int result_relation, int sublevels_up,
+					VarReturningType returning_type);
 
 #endif							/* REWRITEMANIP_H */
-- 
2.43.0

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
new file mode 100644
index 7b1a8a0..52c6d11
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -750,6 +750,11 @@ subquery_planner(PlannerGlobal *glob, Qu
 		flatten_simple_union_all(root);
 
 	/*
+	 * Expand virtual generated columns. XXX more comments
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root);
+
+	/*
 	 * Survey the rangetable to see what kinds of entries are present.  We can
 	 * skip some later processing if relevant SQL features are not used; for
 	 * example if there are no JOIN RTEs we can avoid the expense of doing
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
new file mode 100644
index 5d9225e..0eb7715
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -9,6 +9,7 @@
  *		preprocess_function_rtes
  *		pull_up_subqueries
  *		flatten_simple_union_all
+ *		expand_virtual_generated_columns
  *		do expression preprocessing (including flattening JOIN alias vars)
  *		reduce_outer_joins
  *		remove_useless_result_rtes
@@ -25,6 +26,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,7 +41,9 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -57,6 +61,7 @@ typedef struct pullup_replace_vars_conte
 {
 	PlannerInfo *root;
 	List	   *targetlist;		/* tlist of subquery being pulled up */
+	int			result_relation;	/* the index of the result relation */
 	RangeTblEntry *target_rte;	/* RTE of subquery */
 	Relids		relids;			/* relids within subquery, as numbered after
 								 * pullup (set only if target_rte->lateral) */
@@ -1273,6 +1278,7 @@ pull_up_simple_subquery(PlannerInfo *roo
 	 */
 	rvcontext.root = root;
 	rvcontext.targetlist = subquery->targetList;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	if (rte->lateral)
 	{
@@ -1833,6 +1839,7 @@ pull_up_simple_values(PlannerInfo *root,
 	}
 	rvcontext.root = root;
 	rvcontext.targetlist = tlist;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	rvcontext.relids = NULL;	/* can't be any lateral references here */
 	rvcontext.nullinfo = NULL;
@@ -1992,6 +1999,7 @@ pull_up_constant_function(PlannerInfo *r
 													  1,	/* resno */
 													  NULL, /* resname */
 													  false));	/* resjunk */
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 
 	/*
@@ -2499,6 +2507,10 @@ pullup_replace_vars_callback(Var *var,
 	 */
 	need_phv = (var->varnullingrels != NULL) || rcon->wrap_non_vars;
 
+	/* System columns are not replaced. */
+	if (varattno < InvalidAttrNumber)
+		return (Node *) copyObject(var);
+
 	/*
 	 * If PlaceHolderVars are needed, we cache the modified expressions in
 	 * rcon->rv_cache[].  This is not in hopes of any material speed gain
@@ -2516,85 +2528,43 @@ pullup_replace_vars_callback(Var *var,
 		varattno <= list_length(rcon->targetlist) &&
 		rcon->rv_cache[varattno] != NULL)
 	{
-		/* Just copy the entry and fall through to adjust phlevelsup etc */
+		/* Copy the cached item and adjust its varlevelsup */
 		newnode = copyObject(rcon->rv_cache[varattno]);
+		if (var->varlevelsup > 0)
+			IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
 	}
-	else if (varattno == InvalidAttrNumber)
+	else
 	{
-		/* Must expand whole-tuple reference into RowExpr */
-		RowExpr    *rowexpr;
-		List	   *colnames;
-		List	   *fields;
-		bool		save_wrap_non_vars = rcon->wrap_non_vars;
-		int			save_sublevelsup = context->sublevels_up;
-
-		/*
-		 * If generating an expansion for a var of a named rowtype (ie, this
-		 * is a plain relation RTE), then we must include dummy items for
-		 * dropped columns.  If the var is RECORD (ie, this is a JOIN), then
-		 * omit dropped columns.  In the latter case, attach column names to
-		 * the RowExpr for use of the executor and ruleutils.c.
-		 *
-		 * In order to be able to cache the results, we always generate the
-		 * expansion with varlevelsup = 0, and then adjust below if needed.
-		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, 0 /* not varlevelsup */ ,
-				  var->varreturningtype, var->location,
-				  (var->vartype != RECORDOID),
-				  &colnames, &fields);
-		/* Expand the generated per-field Vars, but don't insert PHVs there */
-		rcon->wrap_non_vars = false;
-		context->sublevels_up = 0;	/* to match the expandRTE output */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
-		rcon->wrap_non_vars = save_wrap_non_vars;
-		context->sublevels_up = save_sublevelsup;
-
-		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
-		rowexpr->row_typeid = var->vartype;
-		rowexpr->row_format = COERCE_IMPLICIT_CAST;
-		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
-		rowexpr->location = var->location;
-		newnode = (Node *) rowexpr;
-
 		/*
-		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
-		 * PlaceHolderVar around the whole RowExpr, rather than putting one
-		 * around each element of the row.  This is because we need the
-		 * expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
-		 * to null by an outer join.
+		 * Generate the replacement expression. This takes care of expanding
+		 * wholerow references, as well as adjusting varlevelsup and
+		 * varreturningtype.
 		 */
-		if (need_phv)
-		{
-			newnode = (Node *)
-				make_placeholder_expr(rcon->root,
-									  (Expr *) newnode,
-									  bms_make_singleton(rcon->varno));
-			/* cache it with the PHV, and with phlevelsup etc not set yet */
-			rcon->rv_cache[InvalidAttrNumber] = copyObject(newnode);
-		}
-	}
-	else
-	{
-		/* Normal case referencing one targetlist element */
-		TargetEntry *tle = get_tle_by_resno(rcon->targetlist, varattno);
-
-		if (tle == NULL)		/* shouldn't happen */
-			elog(ERROR, "could not find attribute %d in subquery targetlist",
-				 varattno);
-
-		/* Make a copy of the tlist item to return */
-		newnode = (Node *) copyObject(tle->expr);
+		newnode = ReplaceVarFromTargetList(var,
+										   rcon->target_rte,
+										   rcon->targetlist,
+										   rcon->result_relation,
+										   REPLACEVARS_REPORT_ERROR,
+										   var->varno);
 
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
 			bool		wrap;
 
-			if (newnode && IsA(newnode, Var) &&
-				((Var *) newnode)->varlevelsup == 0)
+			if (varattno == InvalidAttrNumber)
+			{
+				/*
+				 * A wholerow Var is expanded to a RowExpr, which we wrap with
+				 * a single PlaceHolderVar, rather than putting one around
+				 * each element of the row.  This is because we need the
+				 * expression to yield NULL, not ROW(NULL,NULL,...) when it is
+				 * forced to null by an outer join.
+				 */
+				wrap = true;
+			}
+			else if (newnode && IsA(newnode, Var) &&
+					 ((Var *) newnode)->varlevelsup == var->varlevelsup)
 			{
 				/*
 				 * Simple Vars always escape being wrapped, unless they are
@@ -2616,7 +2586,7 @@ pullup_replace_vars_callback(Var *var,
 				}
 			}
 			else if (newnode && IsA(newnode, PlaceHolderVar) &&
-					 ((PlaceHolderVar *) newnode)->phlevelsup == 0)
+					 ((PlaceHolderVar *) newnode)->phlevelsup == var->varlevelsup)
 			{
 				/* The same rules apply for a PlaceHolderVar */
 				wrap = false;
@@ -2735,14 +2705,25 @@ pullup_replace_vars_callback(Var *var,
 					make_placeholder_expr(rcon->root,
 										  (Expr *) newnode,
 										  bms_make_singleton(rcon->varno));
+				((PlaceHolderVar *) newnode)->phlevelsup = var->varlevelsup;
 
 				/*
 				 * Cache it if possible (ie, if the attno is in range, which
-				 * it probably always should be).
+				 * it probably always should be), ensuring that the cached
+				 * item has phlevelsup = 0.
 				 */
-				if (varattno > InvalidAttrNumber &&
+				if (varattno >= InvalidAttrNumber &&
 					varattno <= list_length(rcon->targetlist))
-					rcon->rv_cache[varattno] = copyObject(newnode);
+				{
+					Node	   *cachenode = copyObject(newnode);
+
+					if (var->varlevelsup > 0)
+						IncrementVarSublevelsUp(cachenode,
+												-((int) var->varlevelsup),
+												0);
+
+					rcon->rv_cache[varattno] = cachenode;
+				}
 			}
 		}
 	}
@@ -2754,7 +2735,7 @@ pullup_replace_vars_callback(Var *var,
 		{
 			Var		   *newvar = (Var *) newnode;
 
-			Assert(newvar->varlevelsup == 0);
+			Assert(newvar->varlevelsup == var->varlevelsup);
 			newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
 													 var->varnullingrels);
 		}
@@ -2762,7 +2743,7 @@ pullup_replace_vars_callback(Var *var,
 		{
 			PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
 
-			Assert(newphv->phlevelsup == 0);
+			Assert(newphv->phlevelsup == var->varlevelsup);
 			newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
 													var->varnullingrels);
 		}
@@ -2825,10 +2806,6 @@ pullup_replace_vars_callback(Var *var,
 		}
 	}
 
-	/* Must adjust varlevelsup if replaced Var is within a subquery */
-	if (var->varlevelsup > 0)
-		IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
-
 	return newnode;
 }
 
@@ -2947,6 +2924,128 @@ flatten_simple_union_all(PlannerInfo *ro
 }
 
 
+/*
+ * expand_virtual_generated_columns
+ *		Expand all virtual generated column references in a query.
+ *
+ * XXX more comments
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			rt_index;
+	ListCell   *lc;
+
+	rt_index = 0;
+	foreach(lc, parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+		TupleDesc	tupdesc;
+
+		++rt_index;
+
+		/*
+		 * Only normal relations can have virtual generated columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		tupdesc = RelationGetDescr(rel);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			List	   *tlist = NIL;
+			pullup_replace_vars_context rvcontext;
+
+			for (int i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+				int			attnum = i + 1;
+				TargetEntry *te;
+
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				{
+					Node	   *defexpr;
+					Oid			attcollid;
+
+					defexpr = build_column_default(rel, attnum);
+					if (defexpr == NULL)
+						elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+							 attnum, RelationGetRelationName(rel));
+
+					/*
+					 * If the column definition has a collation and it is
+					 * different from the collation of the generation
+					 * expression, put a COLLATE clause around the expression.
+					 */
+					attcollid = attr->attcollation;
+					if (attcollid && attcollid != exprCollation(defexpr))
+					{
+						CollateExpr *ce = makeNode(CollateExpr);
+
+						ce->arg = (Expr *) defexpr;
+						ce->collOid = attcollid;
+						ce->location = -1;
+
+						defexpr = (Node *) ce;
+					}
+
+					ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+					te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+				else
+				{
+					Var		   *var;
+
+					var = makeVar(rt_index,
+								  attnum,
+								  attr->atttypid,
+								  attr->atttypmod,
+								  attr->attcollation,
+								  0);
+					te = makeTargetEntry((Expr *) var, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+			}
+
+			Assert(list_length(tlist) > 0);
+
+			rvcontext.root = root;
+			rvcontext.targetlist = tlist;
+			rvcontext.result_relation = parse->resultRelation;
+			rvcontext.target_rte = rte;
+			rvcontext.relids = NULL;
+			rvcontext.nullinfo = NULL;
+			rvcontext.outer_hasSubLinks = NULL;
+			rvcontext.varno = rt_index;
+			rvcontext.wrap_non_vars = false;
+			rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
+										 sizeof(Node *));
+
+			/*
+			 * If the query uses grouping sets, we need a PlaceHolderVar for
+			 * anything that's not a simple Var.  This ensures that
+			 * expressions retain their separate identity so that they will
+			 * match grouping set columns when appropriate.
+			 */
+			if (parse->groupingSets)
+				rvcontext.wrap_non_vars = true;
+
+			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
+		}
+
+		table_close(rel, NoLock);
+	}
+
+	return parse;
+}
+
+
 /*
  * reduce_outer_joins
  *		Attempt to reduce outer joins to plain inner joins.
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
new file mode 100644
index e996bdc..7a39abd
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2190,10 +2190,6 @@ fireRIRrules(Query *parsetree, List *act
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
-	 *
-	 * Finally, we expand any virtual generated columns.  We do this after
-	 * each table's RLS policies are applied because the RLS policies might
-	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2207,11 +2203,10 @@ fireRIRrules(Query *parsetree, List *act
 
 		++rt_index;
 
-		/*
-		 * Only normal relations can have RLS policies or virtual generated
-		 * columns.
-		 */
-		if (rte->rtekind != RTE_RELATION)
+		/* Only normal relations can have RLS policies */
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2295,6 @@ fireRIRrules(Query *parsetree, List *act
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
new file mode 100644
index a115b21..cc268a5
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1736,6 +1736,23 @@ ReplaceVarsFromTargetList_callback(Var *
 								   replace_rte_variables_context *context)
 {
 	ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
+
+	return ReplaceVarFromTargetList(var,
+									rcon->target_rte,
+									rcon->targetlist,
+									rcon->result_relation,
+									rcon->nomatch_option,
+									rcon->nomatch_varno);
+}
+
+Node *
+ReplaceVarFromTargetList(Var *var,
+						 RangeTblEntry *target_rte,
+						 List *targetlist,
+						 int result_relation,
+						 ReplaceVarsNoMatchOption nomatch_option,
+						 int nomatch_varno)
+{
 	TargetEntry *tle;
 
 	if (var->varattno == InvalidAttrNumber)
@@ -1744,6 +1761,7 @@ ReplaceVarsFromTargetList_callback(Var *
 		RowExpr    *rowexpr;
 		List	   *colnames;
 		List	   *fields;
+		ListCell   *lc;
 
 		/*
 		 * If generating an expansion for a var of a named rowtype (ie, this
@@ -1755,15 +1773,27 @@ ReplaceVarsFromTargetList_callback(Var *
 		 * The varreturningtype is copied onto each individual field Var, so
 		 * that it is handled correctly when we recurse.
 		 */
-		expandRTE(rcon->target_rte,
+		expandRTE(target_rte,
 				  var->varno, var->varlevelsup, var->varreturningtype,
 				  var->location, (var->vartype != RECORDOID),
 				  &colnames, &fields);
 		/* Adjust the generated per-field Vars... */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
 		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
+		rowexpr->args = NIL;
+		foreach(lc, fields)
+		{
+			Node	   *field = lfirst(lc);
+
+			if (field != NULL)
+				field = ReplaceVarFromTargetList((Var *) field,
+												 target_rte,
+												 targetlist,
+												 result_relation,
+												 nomatch_option,
+												 nomatch_varno);
+
+			rowexpr->args = lappend(rowexpr->args, field);
+		}
 		rowexpr->row_typeid = var->vartype;
 		rowexpr->row_format = COERCE_IMPLICIT_CAST;
 		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
@@ -1785,12 +1815,12 @@ ReplaceVarsFromTargetList_callback(Var *
 	}
 
 	/* Normal case referencing one targetlist element */
-	tle = get_tle_by_resno(rcon->targetlist, var->varattno);
+	tle = get_tle_by_resno(targetlist, var->varattno);
 
 	if (tle == NULL || tle->resjunk)
 	{
 		/* Failed to find column in targetlist */
-		switch (rcon->nomatch_option)
+		switch (nomatch_option)
 		{
 			case REPLACEVARS_REPORT_ERROR:
 				/* fall through, throw error below */
@@ -1798,7 +1828,7 @@ ReplaceVarsFromTargetList_callback(Var *
 
 			case REPLACEVARS_CHANGE_VARNO:
 				var = copyObject(var);
-				var->varno = rcon->nomatch_varno;
+				var->varno = nomatch_varno;
 				/* we leave the syntactic referent alone */
 				return (Node *) var;
 
@@ -1854,15 +1884,15 @@ ReplaceVarsFromTargetList_callback(Var *
 			 * Copy varreturningtype onto any Vars in the tlist item that
 			 * refer to result_relation (which had better be non-zero).
 			 */
-			if (rcon->result_relation == 0)
+			if (result_relation == 0)
 				elog(ERROR, "variable returning old/new found outside RETURNING list");
 
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
+			SetVarReturningType((Node *) newnode, result_relation,
 								var->varlevelsup, var->varreturningtype);
 
 			/* Wrap it in a ReturningExpr, if needed, per comments above */
 			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varno != result_relation ||
 				((Var *) newnode)->varlevelsup != var->varlevelsup)
 			{
 				ReturningExpr *rexpr = makeNode(ReturningExpr);
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
new file mode 100644
index 0ae57ec..6bc75ac
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -27,6 +27,7 @@ extern void pull_up_sublinks(PlannerInfo
 extern void preprocess_function_rtes(PlannerInfo *root);
 extern void pull_up_subqueries(PlannerInfo *root);
 extern void flatten_simple_union_all(PlannerInfo *root);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root);
 extern void reduce_outer_joins(PlannerInfo *root);
 extern void remove_useless_result_rtes(PlannerInfo *root);
 extern Relids get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
new file mode 100644
index 5128230..afce743
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -85,6 +85,13 @@ extern Node *map_variable_attnos(Node *n
 								 const struct AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
+extern Node *ReplaceVarFromTargetList(Var *var,
+									  RangeTblEntry *target_rte,
+									  List *targetlist,
+									  int result_relation,
+									  ReplaceVarsNoMatchOption nomatch_option,
+									  int nomatch_varno);
+
 extern Node *ReplaceVarsFromTargetList(Node *node,
 									   int target_varno, int sublevels_up,
 									   RangeTblEntry *target_rte,

From 057d8a8f63d7b6b5d8efb5d4f519b8557e264a36 Mon Sep 17 00:00:00 2001
From: Dean Rasheed <dean.a.rasheed@gmail.com>
Date: Wed, 19 Feb 2025 10:30:33 +0000
Subject: [PATCH v4] Expand virtual generated columns in the planner.

Commit 83ea6c54025 added support for virtual generated columns, which
were expanded in the rewriter, in a similar way to view columns.
However, that does not propagate varnullingrels onto the replacement
expressions, which is OK for view columns because they are expanded
inside a subquery, but it is not OK for virtual generated columns
which are expanded directly into the main query and so must be
correctly marked. This lead to various problems with outer join
queries, including "wrong varnullingrels" errors, incorrect results,
and improper outer-join removal.

To fix this, expanded virtual generated columns must be properly
marked, based on the original Var's varnullingrels, and if necessary,
wrapped in PlaceHolderVars. Since PlaceHolderVar is a planner node,
this really has to be done in the planner. To avoid a lot of code
duplication, reuse the planner's subquery-pullup code for this.

Since this now means that the subquery-pullup code may be dealing with
Vars referring to the result relation rather than a subquery, it must
also be taught to handle Vars with non-default varreturningtype
(OLD/NEW references in the RETURNING list), which previously only the
rewriter had to worry about. To avoid even more code duplication
between this code and the rewriter, arrange for pullup_replace_vars()
to reuse ReplaceVarsFromTargetList()'s mutator function. This
eliminates a lot of existing duplicated code between the rewriter and
the planner, and avoids adding even more.
---
 src/backend/optimizer/plan/planner.c      |   6 +
 src/backend/optimizer/prep/prepjointree.c | 262 +++++++++++++++-------
 src/backend/rewrite/rewriteHandler.c      |  23 +-
 src/backend/rewrite/rewriteManip.c        |  50 ++++-
 src/include/optimizer/prep.h              |   1 +
 src/include/rewrite/rewriteManip.h        |   7 +
 src/test/regress/expected/join.out        |  66 ++++++
 src/test/regress/sql/join.sql             |  43 ++++
 8 files changed, 351 insertions(+), 107 deletions(-)

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 7b1a8a0a9f1..6beb58e8f04 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -749,6 +749,12 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 	if (parse->setOperations)
 		flatten_simple_union_all(root);
 
+	/*
+	 * Scan the rangetable for relations with virtual generated columns, and
+	 * expand them.
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root);
+
 	/*
 	 * Survey the rangetable to see what kinds of entries are present.  We can
 	 * skip some later processing if relevant SQL features are not used; for
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5d9225e9909..8fdca35d087 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -9,6 +9,7 @@
  *		preprocess_function_rtes
  *		pull_up_subqueries
  *		flatten_simple_union_all
+ *		expand_virtual_generated_columns
  *		do expression preprocessing (including flattening JOIN alias vars)
  *		reduce_outer_joins
  *		remove_useless_result_rtes
@@ -25,6 +26,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,7 +41,9 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -57,6 +61,7 @@ typedef struct pullup_replace_vars_context
 {
 	PlannerInfo *root;
 	List	   *targetlist;		/* tlist of subquery being pulled up */
+	int			result_relation;	/* the index of the result relation */
 	RangeTblEntry *target_rte;	/* RTE of subquery */
 	Relids		relids;			/* relids within subquery, as numbered after
 								 * pullup (set only if target_rte->lateral) */
@@ -1273,6 +1278,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	rvcontext.root = root;
 	rvcontext.targetlist = subquery->targetList;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	if (rte->lateral)
 	{
@@ -1833,6 +1839,7 @@ pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
 	}
 	rvcontext.root = root;
 	rvcontext.targetlist = tlist;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	rvcontext.relids = NULL;	/* can't be any lateral references here */
 	rvcontext.nullinfo = NULL;
@@ -1992,6 +1999,7 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode,
 													  1,	/* resno */
 													  NULL, /* resname */
 													  false));	/* resjunk */
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 
 	/*
@@ -2490,6 +2498,10 @@ pullup_replace_vars_callback(Var *var,
 	bool		need_phv;
 	Node	   *newnode;
 
+	/* System columns are not replaced. */
+	if (varattno < InvalidAttrNumber)
+		return (Node *) copyObject(var);
+
 	/*
 	 * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
 	 * varnullingrels (unless we find below that the replacement expression is
@@ -2516,85 +2528,43 @@ pullup_replace_vars_callback(Var *var,
 		varattno <= list_length(rcon->targetlist) &&
 		rcon->rv_cache[varattno] != NULL)
 	{
-		/* Just copy the entry and fall through to adjust phlevelsup etc */
+		/* Copy the cached item and adjust its varlevelsup */
 		newnode = copyObject(rcon->rv_cache[varattno]);
+		if (var->varlevelsup > 0)
+			IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
 	}
-	else if (varattno == InvalidAttrNumber)
+	else
 	{
-		/* Must expand whole-tuple reference into RowExpr */
-		RowExpr    *rowexpr;
-		List	   *colnames;
-		List	   *fields;
-		bool		save_wrap_non_vars = rcon->wrap_non_vars;
-		int			save_sublevelsup = context->sublevels_up;
-
 		/*
-		 * If generating an expansion for a var of a named rowtype (ie, this
-		 * is a plain relation RTE), then we must include dummy items for
-		 * dropped columns.  If the var is RECORD (ie, this is a JOIN), then
-		 * omit dropped columns.  In the latter case, attach column names to
-		 * the RowExpr for use of the executor and ruleutils.c.
-		 *
-		 * In order to be able to cache the results, we always generate the
-		 * expansion with varlevelsup = 0, and then adjust below if needed.
+		 * Generate the replacement expression. This takes care of expanding
+		 * wholerow references, as well as adjusting varlevelsup and dealing
+		 * with non-default varreturningtype.
 		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, 0 /* not varlevelsup */ ,
-				  var->varreturningtype, var->location,
-				  (var->vartype != RECORDOID),
-				  &colnames, &fields);
-		/* Expand the generated per-field Vars, but don't insert PHVs there */
-		rcon->wrap_non_vars = false;
-		context->sublevels_up = 0;	/* to match the expandRTE output */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
-		rcon->wrap_non_vars = save_wrap_non_vars;
-		context->sublevels_up = save_sublevelsup;
-
-		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
-		rowexpr->row_typeid = var->vartype;
-		rowexpr->row_format = COERCE_IMPLICIT_CAST;
-		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
-		rowexpr->location = var->location;
-		newnode = (Node *) rowexpr;
-
-		/*
-		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
-		 * PlaceHolderVar around the whole RowExpr, rather than putting one
-		 * around each element of the row.  This is because we need the
-		 * expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
-		 * to null by an outer join.
-		 */
-		if (need_phv)
-		{
-			newnode = (Node *)
-				make_placeholder_expr(rcon->root,
-									  (Expr *) newnode,
-									  bms_make_singleton(rcon->varno));
-			/* cache it with the PHV, and with phlevelsup etc not set yet */
-			rcon->rv_cache[InvalidAttrNumber] = copyObject(newnode);
-		}
-	}
-	else
-	{
-		/* Normal case referencing one targetlist element */
-		TargetEntry *tle = get_tle_by_resno(rcon->targetlist, varattno);
-
-		if (tle == NULL)		/* shouldn't happen */
-			elog(ERROR, "could not find attribute %d in subquery targetlist",
-				 varattno);
-
-		/* Make a copy of the tlist item to return */
-		newnode = (Node *) copyObject(tle->expr);
+		newnode = ReplaceVarFromTargetList(var,
+										   rcon->target_rte,
+										   rcon->targetlist,
+										   rcon->result_relation,
+										   REPLACEVARS_REPORT_ERROR,
+										   0);
 
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
 			bool		wrap;
 
-			if (newnode && IsA(newnode, Var) &&
-				((Var *) newnode)->varlevelsup == 0)
+			if (varattno == InvalidAttrNumber)
+			{
+				/*
+				 * A wholerow Var will have been expanded to a RowExpr, which
+				 * we wrap with a single PlaceHolderVar, rather than putting
+				 * one around each element of the row. This is because we need
+				 * the expression to yield NULL, not ROW(NULL,NULL,...) when
+				 * it is forced to null by an outer join.
+				 */
+				wrap = true;
+			}
+			else if (newnode && IsA(newnode, Var) &&
+					 ((Var *) newnode)->varlevelsup == var->varlevelsup)
 			{
 				/*
 				 * Simple Vars always escape being wrapped, unless they are
@@ -2616,7 +2586,7 @@ pullup_replace_vars_callback(Var *var,
 				}
 			}
 			else if (newnode && IsA(newnode, PlaceHolderVar) &&
-					 ((PlaceHolderVar *) newnode)->phlevelsup == 0)
+					 ((PlaceHolderVar *) newnode)->phlevelsup == var->varlevelsup)
 			{
 				/* The same rules apply for a PlaceHolderVar */
 				wrap = false;
@@ -2735,14 +2705,25 @@ pullup_replace_vars_callback(Var *var,
 					make_placeholder_expr(rcon->root,
 										  (Expr *) newnode,
 										  bms_make_singleton(rcon->varno));
+				((PlaceHolderVar *) newnode)->phlevelsup = var->varlevelsup;
 
 				/*
 				 * Cache it if possible (ie, if the attno is in range, which
-				 * it probably always should be).
+				 * it probably always should be), ensuring that the cached
+				 * item has phlevelsup = 0.
 				 */
-				if (varattno > InvalidAttrNumber &&
+				if (varattno >= InvalidAttrNumber &&
 					varattno <= list_length(rcon->targetlist))
-					rcon->rv_cache[varattno] = copyObject(newnode);
+				{
+					Node	   *cachenode = copyObject(newnode);
+
+					if (var->varlevelsup > 0)
+						IncrementVarSublevelsUp(cachenode,
+												-((int) var->varlevelsup),
+												0);
+
+					rcon->rv_cache[varattno] = cachenode;
+				}
 			}
 		}
 	}
@@ -2754,7 +2735,7 @@ pullup_replace_vars_callback(Var *var,
 		{
 			Var		   *newvar = (Var *) newnode;
 
-			Assert(newvar->varlevelsup == 0);
+			Assert(newvar->varlevelsup == var->varlevelsup);
 			newvar->varnullingrels = bms_add_members(newvar->varnullingrels,
 													 var->varnullingrels);
 		}
@@ -2762,7 +2743,7 @@ pullup_replace_vars_callback(Var *var,
 		{
 			PlaceHolderVar *newphv = (PlaceHolderVar *) newnode;
 
-			Assert(newphv->phlevelsup == 0);
+			Assert(newphv->phlevelsup == var->varlevelsup);
 			newphv->phnullingrels = bms_add_members(newphv->phnullingrels,
 													var->varnullingrels);
 		}
@@ -2825,10 +2806,6 @@ pullup_replace_vars_callback(Var *var,
 		}
 	}
 
-	/* Must adjust varlevelsup if replaced Var is within a subquery */
-	if (var->varlevelsup > 0)
-		IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
-
 	return newnode;
 }
 
@@ -2947,6 +2924,135 @@ flatten_simple_union_all(PlannerInfo *root)
 }
 
 
+/*
+ * expand_virtual_generated_columns
+ *		Expand all virtual generated column references in a query.
+ *
+ * This scans the rangetable for relations with virtual generated columns, and
+ * replaces all Var nodes in the query that refer to such columns with the
+ * appropriate expressions.  Note that this happens after subquery pullup, and
+ * it does not recurse into any remaining subqueries; that is taken care of
+ * when those subqueries are planned.
+ *
+ * Returns a modified copy of the query tree, if any relations with virtual
+ * generated columns are present.
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			rt_index;
+	ListCell   *lc;
+
+	rt_index = 0;
+	foreach(lc, parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+		TupleDesc	tupdesc;
+
+		++rt_index;
+
+		/*
+		 * Only normal relations can have virtual generated columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		tupdesc = RelationGetDescr(rel);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			List	   *tlist = NIL;
+			pullup_replace_vars_context rvcontext;
+
+			for (int i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+				int			attnum = i + 1;
+				TargetEntry *te;
+
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				{
+					Node	   *defexpr;
+					Oid			attcollid;
+
+					defexpr = build_column_default(rel, attnum);
+					if (defexpr == NULL)
+						elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+							 attnum, RelationGetRelationName(rel));
+
+					/*
+					 * If the column definition has a collation and it is
+					 * different from the collation of the generation
+					 * expression, put a COLLATE clause around the expression.
+					 */
+					attcollid = attr->attcollation;
+					if (attcollid && attcollid != exprCollation(defexpr))
+					{
+						CollateExpr *ce = makeNode(CollateExpr);
+
+						ce->arg = (Expr *) defexpr;
+						ce->collOid = attcollid;
+						ce->location = -1;
+
+						defexpr = (Node *) ce;
+					}
+
+					ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+					te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+				else
+				{
+					Var		   *var;
+
+					var = makeVar(rt_index,
+								  attnum,
+								  attr->atttypid,
+								  attr->atttypmod,
+								  attr->attcollation,
+								  0);
+					te = makeTargetEntry((Expr *) var, attnum, 0, false);
+					tlist = lappend(tlist, te);
+				}
+			}
+
+			Assert(list_length(tlist) > 0);
+
+			rvcontext.root = root;
+			rvcontext.targetlist = tlist;
+			rvcontext.result_relation = parse->resultRelation;
+			rvcontext.target_rte = rte;
+			rvcontext.relids = NULL;
+			rvcontext.nullinfo = NULL;
+			rvcontext.outer_hasSubLinks = NULL;
+			rvcontext.varno = rt_index;
+			rvcontext.wrap_non_vars = false;
+			rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
+										 sizeof(Node *));
+
+			/*
+			 * If the query uses grouping sets, we need a PlaceHolderVar for
+			 * anything that's not a simple Var.  This ensures that
+			 * expressions retain their separate identity so that they will
+			 * match grouping set columns when appropriate.
+			 */
+			if (parse->groupingSets)
+				rvcontext.wrap_non_vars = true;
+
+			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
+		}
+
+		table_close(rel, NoLock);
+	}
+
+	return parse;
+}
+
+
 /*
  * reduce_outer_joins
  *		Attempt to reduce outer joins to plain inner joins.
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e996bdc0d21..7a39abd4d86 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2190,10 +2190,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
-	 *
-	 * Finally, we expand any virtual generated columns.  We do this after
-	 * each table's RLS policies are applied because the RLS policies might
-	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2207,11 +2203,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/*
-		 * Only normal relations can have RLS policies or virtual generated
-		 * columns.
-		 */
-		if (rte->rtekind != RTE_RELATION)
+		/* Only normal relations can have RLS policies */
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2295,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 9433548d279..e81624f9b09 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1814,6 +1814,23 @@ ReplaceVarsFromTargetList_callback(Var *var,
 								   replace_rte_variables_context *context)
 {
 	ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
+
+	return ReplaceVarFromTargetList(var,
+									rcon->target_rte,
+									rcon->targetlist,
+									rcon->result_relation,
+									rcon->nomatch_option,
+									rcon->nomatch_varno);
+}
+
+Node *
+ReplaceVarFromTargetList(Var *var,
+						 RangeTblEntry *target_rte,
+						 List *targetlist,
+						 int result_relation,
+						 ReplaceVarsNoMatchOption nomatch_option,
+						 int nomatch_varno)
+{
 	TargetEntry *tle;
 
 	if (var->varattno == InvalidAttrNumber)
@@ -1822,6 +1839,7 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		RowExpr    *rowexpr;
 		List	   *colnames;
 		List	   *fields;
+		ListCell   *lc;
 
 		/*
 		 * If generating an expansion for a var of a named rowtype (ie, this
@@ -1833,15 +1851,27 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		 * The varreturningtype is copied onto each individual field Var, so
 		 * that it is handled correctly when we recurse.
 		 */
-		expandRTE(rcon->target_rte,
+		expandRTE(target_rte,
 				  var->varno, var->varlevelsup, var->varreturningtype,
 				  var->location, (var->vartype != RECORDOID),
 				  &colnames, &fields);
 		/* Adjust the generated per-field Vars... */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
 		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
+		rowexpr->args = NIL;
+		foreach(lc, fields)
+		{
+			Node	   *field = lfirst(lc);
+
+			if (field != NULL)
+				field = ReplaceVarFromTargetList((Var *) field,
+												 target_rte,
+												 targetlist,
+												 result_relation,
+												 nomatch_option,
+												 nomatch_varno);
+
+			rowexpr->args = lappend(rowexpr->args, field);
+		}
 		rowexpr->row_typeid = var->vartype;
 		rowexpr->row_format = COERCE_IMPLICIT_CAST;
 		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
@@ -1863,12 +1893,12 @@ ReplaceVarsFromTargetList_callback(Var *var,
 	}
 
 	/* Normal case referencing one targetlist element */
-	tle = get_tle_by_resno(rcon->targetlist, var->varattno);
+	tle = get_tle_by_resno(targetlist, var->varattno);
 
 	if (tle == NULL || tle->resjunk)
 	{
 		/* Failed to find column in targetlist */
-		switch (rcon->nomatch_option)
+		switch (nomatch_option)
 		{
 			case REPLACEVARS_REPORT_ERROR:
 				/* fall through, throw error below */
@@ -1876,7 +1906,7 @@ ReplaceVarsFromTargetList_callback(Var *var,
 
 			case REPLACEVARS_CHANGE_VARNO:
 				var = copyObject(var);
-				var->varno = rcon->nomatch_varno;
+				var->varno = nomatch_varno;
 				/* we leave the syntactic referent alone */
 				return (Node *) var;
 
@@ -1932,15 +1962,15 @@ ReplaceVarsFromTargetList_callback(Var *var,
 			 * Copy varreturningtype onto any Vars in the tlist item that
 			 * refer to result_relation (which had better be non-zero).
 			 */
-			if (rcon->result_relation == 0)
+			if (result_relation == 0)
 				elog(ERROR, "variable returning old/new found outside RETURNING list");
 
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
+			SetVarReturningType((Node *) newnode, result_relation,
 								var->varlevelsup, var->varreturningtype);
 
 			/* Wrap it in a ReturningExpr, if needed, per comments above */
 			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varno != result_relation ||
 				((Var *) newnode)->varlevelsup != var->varlevelsup)
 			{
 				ReturningExpr *rexpr = makeNode(ReturningExpr);
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 0ae57ec24a4..6bc75ac9f38 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -27,6 +27,7 @@ extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
 extern void pull_up_subqueries(PlannerInfo *root);
 extern void flatten_simple_union_all(PlannerInfo *root);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root);
 extern void reduce_outer_joins(PlannerInfo *root);
 extern void remove_useless_result_rtes(PlannerInfo *root);
 extern Relids get_relids_in_jointree(Node *jtnode, bool include_outer_joins,
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 5ec475c63e9..8ca0face062 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -89,6 +89,13 @@ extern Node *map_variable_attnos(Node *node,
 								 const struct AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
+extern Node *ReplaceVarFromTargetList(Var *var,
+									  RangeTblEntry *target_rte,
+									  List *targetlist,
+									  int result_relation,
+									  ReplaceVarsNoMatchOption nomatch_option,
+									  int nomatch_varno);
+
 extern Node *ReplaceVarsFromTargetList(Node *node,
 									   int target_varno, int sublevels_up,
 									   RangeTblEntry *target_rte,
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index a57bb18c24f..e787792ece1 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3514,6 +3514,72 @@ order by c.name;
  C    |      |       |      
 (3 rows)
 
+rollback;
+--
+-- test NULL behavior of virtual generated columns
+--
+begin;
+create temp table t (
+     a int primary key,
+     b int generated always as (1 + 1),
+     c int generated always as (a),
+     d int generated always as (a * 10),
+     e int generated always as (coalesce(a, 100))
+);
+insert into t values (1), (2);
+-- test propagtion of varnullingrels
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a),
+       sum(t2.e) over (partition by t2.a)
+from t as t1 left join t as t2 on (t1.a = t2.a)
+order by t1.a;
+ sum | sum | sum | sum 
+-----+-----+-----+-----
+   2 |   1 |  10 |   1
+   2 |   2 |  20 |   2
+(2 rows)
+
+select t1.*, t2.*
+from t as t1 left join t as t2 on false
+order by t1.a;
+ a | b | c | d  | e | a | b | c | d | e 
+---+---+---+----+---+---+---+---+---+---
+ 1 | 2 | 1 | 10 | 1 |   |   |   |   |  
+ 2 | 2 | 2 | 20 | 2 |   |   |   |   |  
+(2 rows)
+
+explain (costs off)
+select t1.a
+from t as t1 left join t as t2 on (t1.a = t2.a)
+where coalesce(t2.d, 1) = 1;
+                QUERY PLAN                
+------------------------------------------
+ Hash Left Join
+   Hash Cond: (t1.a = t2.a)
+   Filter: (COALESCE((t2.a * 10), 1) = 1)
+   ->  Seq Scan on t t1
+   ->  Hash
+         ->  Seq Scan on t t2
+(6 rows)
+
+-- grouping sets requires PlaceHolderVar for non-Var clauses
+select * from t
+group by grouping sets (a, b, c, d, e)
+having b = 2;
+ a | b | c | d | e 
+---+---+---+---+---
+   | 2 |   |   |  
+(1 row)
+
+select * from t
+group by grouping sets (a, b, c, d, e)
+having c = 2;
+ a | b | c | d | e 
+---+---+---+---+---
+   |   | 2 |   |  
+(1 row)
+
 rollback;
 --
 -- test incorrect handling of placeholders that only appear in targetlists,
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index c29d13b9fed..828cbdfd9db 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -1044,6 +1044,49 @@ order by c.name;
 
 rollback;
 
+--
+-- test NULL behavior of virtual generated columns
+--
+begin;
+
+create temp table t (
+     a int primary key,
+     b int generated always as (1 + 1),
+     c int generated always as (a),
+     d int generated always as (a * 10),
+     e int generated always as (coalesce(a, 100))
+);
+
+insert into t values (1), (2);
+
+-- test propagtion of varnullingrels
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a),
+       sum(t2.e) over (partition by t2.a)
+from t as t1 left join t as t2 on (t1.a = t2.a)
+order by t1.a;
+
+select t1.*, t2.*
+from t as t1 left join t as t2 on false
+order by t1.a;
+
+explain (costs off)
+select t1.a
+from t as t1 left join t as t2 on (t1.a = t2.a)
+where coalesce(t2.d, 1) = 1;
+
+-- grouping sets requires PlaceHolderVar for non-Var clauses
+select * from t
+group by grouping sets (a, b, c, d, e)
+having b = 2;
+
+select * from t
+group by grouping sets (a, b, c, d, e)
+having c = 2;
+
+rollback;
+
 --
 -- test incorrect handling of placeholders that only appear in targetlists,
 -- per bug #6154
-- 
2.43.0

From c3eee14e92508cc614087dad155e2482cb4b71e0 Mon Sep 17 00:00:00 2001
From: jian he <jian.universality@gmail.com>
Date: Fri, 21 Feb 2025 12:34:44 +0800
Subject: [PATCH v4 1/1] fix expanding virtual generated columns with grouping
 sets

---
 src/backend/optimizer/prep/prepjointree.c | 17 ++++++++++++++---
 src/test/regress/expected/join.out        |  8 ++++++++
 src/test/regress/sql/join.sql             |  4 ++++
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 8fdca35d087..aad51f3d0a0 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -70,6 +70,8 @@ typedef struct pullup_replace_vars_context
 	bool	   *outer_hasSubLinks;	/* -> outer query's hasSubLinks */
 	int			varno;			/* varno of subquery */
 	bool		wrap_non_vars;	/* do we need all non-Var outputs to be PHVs? */
+	bool		wrap_vars;		/* do we need all Var outputs to be PHVs?
+								 * this may needed for GroupingSet */
 	Node	  **rv_cache;		/* cache for results with PHVs */
 } pullup_replace_vars_context;
 
@@ -1295,6 +1297,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	rvcontext.varno = varno;
 	/* this flag will be set below, if needed */
 	rvcontext.wrap_non_vars = false;
+	rvcontext.wrap_vars = false;
 	/* initialize cache array with indexes 0 .. length(tlist) */
 	rvcontext.rv_cache = palloc0((list_length(subquery->targetList) + 1) *
 								 sizeof(Node *));
@@ -1846,6 +1849,7 @@ pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
 	rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
 	rvcontext.varno = varno;
 	rvcontext.wrap_non_vars = false;
+	rvcontext.wrap_vars = false;
 	/* initialize cache array with indexes 0 .. length(tlist) */
 	rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
 								 sizeof(Node *));
@@ -2014,6 +2018,7 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode,
 	rvcontext.varno = ((RangeTblRef *) jtnode)->rtindex;
 	/* this flag will be set below, if needed */
 	rvcontext.wrap_non_vars = false;
+	rvcontext.wrap_vars = false;
 	/* initialize cache array with indexes 0 .. length(tlist) */
 	rvcontext.rv_cache = palloc0((list_length(rvcontext.targetlist) + 1) *
 								 sizeof(Node *));
@@ -2699,6 +2704,9 @@ pullup_replace_vars_callback(Var *var,
 				}
 			}
 
+			if (!wrap && rcon->wrap_vars && rcon->wrap_non_vars)
+				wrap = true;
+
 			if (wrap)
 			{
 				newnode = (Node *)
@@ -3002,7 +3010,7 @@ expand_virtual_generated_columns(PlannerInfo *root)
 
 					ChangeVarNodes(defexpr, 1, rt_index, 0);
 
-					te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+					te = makeTargetEntry((Expr *) defexpr, attnum, NULL, false);
 					tlist = lappend(tlist, te);
 				}
 				else
@@ -3015,7 +3023,7 @@ expand_virtual_generated_columns(PlannerInfo *root)
 								  attr->atttypmod,
 								  attr->attcollation,
 								  0);
-					te = makeTargetEntry((Expr *) var, attnum, 0, false);
+					te = makeTargetEntry((Expr *) var, attnum, NULL, false);
 					tlist = lappend(tlist, te);
 				}
 			}
@@ -3036,12 +3044,15 @@ expand_virtual_generated_columns(PlannerInfo *root)
 
 			/*
 			 * If the query uses grouping sets, we need a PlaceHolderVar for
-			 * anything that's not a simple Var.  This ensures that
+			 * anything.  This ensures that
 			 * expressions retain their separate identity so that they will
 			 * match grouping set columns when appropriate.
 			 */
 			if (parse->groupingSets)
+			{
 				rvcontext.wrap_non_vars = true;
+				rvcontext.wrap_vars = true;
+			}
 
 			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
 		}
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index e787792ece1..26e282a40dc 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -3580,6 +3580,14 @@ having c = 2;
    |   | 2 |   |  
 (1 row)
 
+select a,c from t
+group by grouping sets (a,c)
+having c = 2;
+ a | c 
+---+---
+   | 2
+(1 row)
+
 rollback;
 --
 -- test incorrect handling of placeholders that only appear in targetlists,
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index 828cbdfd9db..0abecd7e54e 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -1085,6 +1085,10 @@ select * from t
 group by grouping sets (a, b, c, d, e)
 having c = 2;
 
+select a,c from t
+group by grouping sets (a,c)
+having c = 2;
+
 rollback;
 
 --
-- 
2.34.1

From 0d342b17641179e3b514412bd3b216572b6f0a7a Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Fri, 21 Feb 2025 09:46:59 +0900
Subject: [PATCH v5 1/2] Expand virtual generated columns in the planner

Commit 83ea6c540 added support for virtual generated columns, which
were expanded in the rewriter, in a similar way to view columns.
However, this approach has several issues.  If a Var referencing a
virtual generated column has any varnullingrels, there would be no way
to propagate the varnullingrels into the generation expression,
leading to "wrong varnullingrels" errors and improper outer-join
removal.  Additionally, if such a Var comes from the nullable side of
an outer join, we may need to wrap the generation expression in a
PlaceHolderVar to ensure that it is evaluated at the right place and
hence is forced to null when the outer join should do so.  In some
cases, such as when the query uses grouping sets, we also need a
PlaceHolderVar for anything that's not a simple Var to isolate
subexpressions.  All of this cannot be achieved in the rewriter.

To fix this, the patch expands the virtual generated columns in the
planner and leverages the pullup_replace_vars architecture to avoid
code duplication.  This requires handling the OLD/NEW RETURNING list
Vars in pullup_replace_vars_callback.
---
 src/backend/optimizer/plan/planner.c          |   7 +
 src/backend/optimizer/prep/prepjointree.c     | 186 ++++++++++++++++++
 src/backend/rewrite/rewriteHandler.c          |  87 ++++----
 src/backend/rewrite/rewriteManip.c            |   2 +-
 src/include/optimizer/prep.h                  |   1 +
 src/include/rewrite/rewriteHandler.h          |   1 +
 src/include/rewrite/rewriteManip.h            |   3 +
 .../regress/expected/generated_virtual.out    |  89 +++++++++
 src/test/regress/sql/generated_virtual.sql    |  38 ++++
 9 files changed, 372 insertions(+), 42 deletions(-)

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 7b1a8a0a9f1..201487eaf42 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -717,6 +717,13 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 	 */
 	replace_empty_jointree(parse);
 
+	/*
+	 * Scan the rangetable for relations with virtual generated columns, and
+	 * replace all Var nodes in the query that reference these columns with
+	 * the generation expressions.
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root);
+
 	/*
 	 * Look for ANY and EXISTS SubLinks in WHERE and JOIN/ON clauses, and try
 	 * to transform them into joins.  Note that this step does not descend
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5d9225e9909..89b1ff2db87 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -5,6 +5,7 @@
  *
  * NOTE: the intended sequence for invoking these operations is
  *		replace_empty_jointree
+ *		expand_virtual_generated_columns
  *		pull_up_sublinks
  *		preprocess_function_rtes
  *		pull_up_subqueries
@@ -25,6 +26,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,7 +41,9 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -57,6 +61,7 @@ typedef struct pullup_replace_vars_context
 {
 	PlannerInfo *root;
 	List	   *targetlist;		/* tlist of subquery being pulled up */
+	int			result_relation;
 	RangeTblEntry *target_rte;	/* RTE of subquery */
 	Relids		relids;			/* relids within subquery, as numbered after
 								 * pullup (set only if target_rte->lateral) */
@@ -421,6 +426,128 @@ replace_empty_jointree(Query *parse)
 	parse->jointree->fromlist = list_make1(rtr);
 }
 
+/*
+ * expand_virtual_generated_columns
+ *		Expand all virtual generated column references in a query.
+ *
+ * This scans the rangetable for relations with virtual generated columns, and
+ * replaces all Var nodes in the query that reference these columns with the
+ * appropriate expressions.  Note that we do not recurse into subqueries; that
+ * is taken care of when the subqueries are planned.
+ *
+ * Returns a modified copy of the query tree, if any relations with virtual
+ * generated columns are present.
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			rt_index;
+	ListCell   *lc;
+
+	rt_index = 0;
+	foreach(lc, parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+		TupleDesc	tupdesc;
+
+		++rt_index;
+
+		/*
+		 * Only normal relations can have virtual generated columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		tupdesc = RelationGetDescr(rel);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			List	   *tlist = NIL;
+			pullup_replace_vars_context rvcontext;
+
+			for (int i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+				TargetEntry *tle;
+
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				{
+					Node	   *defexpr = build_generation_expression(rel, i + 1);
+
+					ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+					tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
+					tlist = lappend(tlist, tle);
+				}
+				else
+				{
+					Var		   *var;
+
+					var = makeVar(rt_index,
+								  i + 1,
+								  attr->atttypid,
+								  attr->atttypmod,
+								  attr->attcollation,
+								  0);
+
+					tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
+					tlist = lappend(tlist, tle);
+				}
+			}
+
+			Assert(list_length(tlist) > 0);
+			Assert(!rte->lateral);
+
+			/*
+			 * The relation's targetlist items are now in the appropriate form
+			 * to insert into the query, except that we may need to wrap them
+			 * in PlaceHolderVars.  Set up required context data for
+			 * pullup_replace_vars.
+			 */
+			rvcontext.root = root;
+			rvcontext.targetlist = tlist;
+			rvcontext.result_relation = parse->resultRelation;
+			rvcontext.target_rte = rte;
+			/* won't need these values */
+			rvcontext.relids = NULL;
+			rvcontext.nullinfo = NULL;
+			/* pass NULL for outer_hasSubLinks */
+			rvcontext.outer_hasSubLinks = NULL;
+			rvcontext.varno = rt_index;
+			/* this flag will be set below, if needed */
+			rvcontext.wrap_non_vars = false;
+			/* initialize cache array with indexes 0 .. length(tlist) */
+			rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
+										 sizeof(Node *));
+
+			/*
+			 * If the query uses grouping sets, we need a PlaceHolderVar for
+			 * anything that's not a simple Var.  Again, this ensures that
+			 * expressions retain their separate identity so that they will
+			 * match grouping set columns when appropriate.  (It'd be
+			 * sufficient to wrap values used in grouping set columns, and do
+			 * so only in non-aggregated portions of the tlist and havingQual,
+			 * but that would require a lot of infrastructure that
+			 * pullup_replace_vars hasn't currently got.)
+			 */
+			if (parse->groupingSets)
+				rvcontext.wrap_non_vars = true;
+
+			/*
+			 * Apply pullup variable replacement throughout the query tree.
+			 */
+			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
+		}
+
+		table_close(rel, NoLock);
+	}
+
+	return parse;
+}
+
 /*
  * pull_up_sublinks
  *		Attempt to pull up ANY and EXISTS SubLinks to be treated as
@@ -1184,6 +1311,13 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	replace_empty_jointree(subquery);
 
+	/*
+	 * Scan the rangetable for relations with virtual generated columns, and
+	 * replace all Var nodes in the query that reference these columns with
+	 * the generation expressions.
+	 */
+	subquery = subroot->parse = expand_virtual_generated_columns(subroot);
+
 	/*
 	 * Pull up any SubLinks within the subquery's quals, so that we don't
 	 * leave unoptimized SubLinks behind.
@@ -1273,6 +1407,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	rvcontext.root = root;
 	rvcontext.targetlist = subquery->targetList;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	if (rte->lateral)
 	{
@@ -1833,6 +1968,7 @@ pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
 	}
 	rvcontext.root = root;
 	rvcontext.targetlist = tlist;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	rvcontext.relids = NULL;	/* can't be any lateral references here */
 	rvcontext.nullinfo = NULL;
@@ -1993,6 +2129,7 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode,
 													  NULL, /* resname */
 													  false));	/* resjunk */
 	rvcontext.target_rte = rte;
+	rvcontext.result_relation = 0;
 
 	/*
 	 * Since this function was reduced to a Const, it doesn't contain any
@@ -2490,6 +2627,10 @@ pullup_replace_vars_callback(Var *var,
 	bool		need_phv;
 	Node	   *newnode;
 
+	/* System columns are not replaced. */
+	if (varattno < InvalidAttrNumber)
+		return (Node *) copyObject(var);
+
 	/*
 	 * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
 	 * varnullingrels (unless we find below that the replacement expression is
@@ -2559,6 +2700,18 @@ pullup_replace_vars_callback(Var *var,
 		rowexpr->location = var->location;
 		newnode = (Node *) rowexpr;
 
+		/* Handle any OLD/NEW RETURNING list Vars */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+			rexpr->retlevelsup = 0;
+			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+			rexpr->retexpr = (Expr *) newnode;
+
+			newnode = (Node *) rexpr;
+		}
+
 		/*
 		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
 		 * PlaceHolderVar around the whole RowExpr, rather than putting one
@@ -2588,6 +2741,39 @@ pullup_replace_vars_callback(Var *var,
 		/* Make a copy of the tlist item to return */
 		newnode = (Node *) copyObject(tle->expr);
 
+		/* Handle any OLD/NEW RETURNING list Vars */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			/*
+			 * Copy varreturningtype onto any Vars in the tlist item that
+			 * refer to result_relation (which had better be non-zero).
+			 */
+			if (rcon->result_relation == 0)
+				elog(ERROR, "variable returning old/new found outside RETURNING list");
+
+			SetVarReturningType((Node *) newnode, rcon->result_relation,
+								0, var->varreturningtype);
+
+			/*
+			 * If the replacement expression in the targetlist is not simply a
+			 * Var referencing result_relation, wrap it in a ReturningExpr
+			 * node, so that the executor returns NULL if the OLD/NEW row does
+			 * not exist.
+			 */
+			if (!IsA(newnode, Var) ||
+				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varlevelsup != var->varlevelsup)
+			{
+				ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+				rexpr->retlevelsup = 0;
+				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+				rexpr->retexpr = (Expr *) newnode;
+
+				newnode = (Node *) rexpr;
+			}
+		}
+
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e996bdc0d21..c07d3ce203f 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2207,11 +2207,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/*
-		 * Only normal relations can have RLS policies or virtual generated
-		 * columns.
-		 */
-		if (rte->rtekind != RTE_RELATION)
+		/* Only normal relations can have RLS policies */
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2299,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
@@ -4456,36 +4445,12 @@ expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
 
 			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			{
-				Node	   *defexpr;
-				int			attnum = i + 1;
-				Oid			attcollid;
 				TargetEntry *te;
-
-				defexpr = build_column_default(rel, attnum);
-				if (defexpr == NULL)
-					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
-						 attnum, RelationGetRelationName(rel));
-
-				/*
-				 * If the column definition has a collation and it is
-				 * different from the collation of the generation expression,
-				 * put a COLLATE clause around the expression.
-				 */
-				attcollid = attr->attcollation;
-				if (attcollid && attcollid != exprCollation(defexpr))
-				{
-					CollateExpr *ce = makeNode(CollateExpr);
-
-					ce->arg = (Expr *) defexpr;
-					ce->collOid = attcollid;
-					ce->location = -1;
-
-					defexpr = (Node *) ce;
-				}
+				Node	   *defexpr = build_generation_expression(rel, i + 1);
 
 				ChangeVarNodes(defexpr, 1, rt_index, 0);
 
-				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				te = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
 				tlist = lappend(tlist, te);
 			}
 		}
@@ -4528,6 +4493,46 @@ expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
 	return node;
 }
 
+/*
+ * Build the generation expression for the virtual generated column.
+ *
+ * Error out if there is no generation expression found for the given column.
+ */
+Node *
+build_generation_expression(Relation rel, int attrno)
+{
+	TupleDesc	rd_att = RelationGetDescr(rel);
+	Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
+	Node	   *defexpr;
+	Oid			attcollid;
+
+	Assert(att_tup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL);
+
+	defexpr = build_column_default(rel, attrno);
+	if (defexpr == NULL)
+		elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+			 attrno, RelationGetRelationName(rel));
+
+	/*
+	 * If the column definition has a collation and it is different from the
+	 * collation of the generation expression, put a COLLATE clause around the
+	 * expression.
+	 */
+	attcollid = att_tup->attcollation;
+	if (attcollid && attcollid != exprCollation(defexpr))
+	{
+		CollateExpr *ce = makeNode(CollateExpr);
+
+		ce->arg = (Expr *) defexpr;
+		ce->collOid = attcollid;
+		ce->location = -1;
+
+		defexpr = (Node *) ce;
+	}
+
+	return defexpr;
+}
+
 
 /*
  * QueryRewrite -
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 9433548d279..6994b8c5425 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1010,7 +1010,7 @@ SetVarReturningType_walker(Node *node, SetVarReturningType_context *context)
 	return expression_tree_walker(node, SetVarReturningType_walker, context);
 }
 
-static void
+void
 SetVarReturningType(Node *node, int result_relation, int sublevels_up,
 					VarReturningType returning_type)
 {
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 0ae57ec24a4..0a61cd126b7 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -23,6 +23,7 @@
  */
 extern void transform_MERGE_to_join(Query *parse);
 extern void replace_empty_jointree(Query *parse);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root);
 extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
 extern void pull_up_subqueries(PlannerInfo *root);
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 88fe13c5f4f..99cab1a3bfa 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -39,5 +39,6 @@ extern void error_view_not_updatable(Relation view,
 									 const char *detail);
 
 extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+extern Node *build_generation_expression(Relation rel, int attrno);
 
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 5ec475c63e9..466edd7c1c2 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -55,6 +55,9 @@ extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
+extern void SetVarReturningType(Node *node, int result_relation, int sublevels_up,
+								VarReturningType returning_type);
+
 extern bool rangeTableEntry_used(Node *node, int rt_index,
 								 int sublevels_up);
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 35638812be9..cb2383469c6 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1398,3 +1398,92 @@ SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT
 ----------+---------+--------------
 (0 rows)
 
+--
+-- test the expansion of virtual generated columns
+--
+create table gtest32 (
+  a int,
+  b int generated always as (a * 2),
+  c int generated always as (10 + 10),
+  d int generated always as (coalesce(a, 100))
+);
+insert into gtest32 values (1), (2);
+-- Ensure that nullingrel bits are propagated into the generation expression
+explain (costs off)
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+                      QUERY PLAN                      
+------------------------------------------------------
+ Sort
+   Sort Key: t1.a
+   ->  WindowAgg
+         ->  Sort
+               Sort Key: t2.a
+               ->  Merge Left Join
+                     Merge Cond: (t1.a = t2.a)
+                     ->  Sort
+                           Sort Key: t1.a
+                           ->  Seq Scan on gtest32 t1
+                     ->  Sort
+                           Sort Key: t2.a
+                           ->  Seq Scan on gtest32 t2
+(13 rows)
+
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+ sum | sum | sum 
+-----+-----+-----
+   2 |  20 |   1
+   4 |  20 |   2
+(2 rows)
+
+-- Ensure that the generation expressions are wrapped into PHVs if needed
+explain (verbose, costs off)
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+                      QUERY PLAN                      
+------------------------------------------------------
+ Nested Loop Left Join
+   Output: a, (a * 2), (20), (COALESCE(a, 100))
+   Join Filter: false
+   ->  Seq Scan on generated_virtual_tests.gtest32 t1
+         Output: t1.a, t1.b, t1.c, t1.d
+   ->  Result
+         Output: a, 20, COALESCE(a, 100)
+         One-Time Filter: false
+(8 rows)
+
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+ a | b | c | d 
+---+---+---+---
+   |   |   |  
+   |   |   |  
+(2 rows)
+
+explain (verbose, costs off)
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+                     QUERY PLAN                      
+-----------------------------------------------------
+ HashAggregate
+   Output: a, ((a * 2)), (20), (COALESCE(a, 100))
+   Hash Key: t.a
+   Hash Key: (t.a * 2)
+   Hash Key: 20
+   Hash Key: COALESCE(t.a, 100)
+   Filter: ((20) = 20)
+   ->  Seq Scan on generated_virtual_tests.gtest32 t
+         Output: a, (a * 2), 20, COALESCE(a, 100)
+(9 rows)
+
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+ a | b | c  | d 
+---+---+----+---
+   |   | 20 |  
+(1 row)
+
+drop table gtest32;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34870813910..25b28a83b1b 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -732,3 +732,41 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 -- sanity check of system catalog
 SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+
+--
+-- test the expansion of virtual generated columns
+--
+
+create table gtest32 (
+  a int,
+  b int generated always as (a * 2),
+  c int generated always as (10 + 10),
+  d int generated always as (coalesce(a, 100))
+);
+
+insert into gtest32 values (1), (2);
+
+-- Ensure that nullingrel bits are propagated into the generation expression
+explain (costs off)
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+
+-- Ensure that the generation expressions are wrapped into PHVs if needed
+explain (verbose, costs off)
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+
+explain (verbose, costs off)
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+
+drop table gtest32;
-- 
2.43.0

From 5c25df770ea17766f2a73a27a164e5ecf99740b0 Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Fri, 21 Feb 2025 14:01:56 +0900
Subject: [PATCH v5 2/2] Eliminate code duplication in replace_rte_variables
 callbacks

The callback functions ReplaceVarsFromTargetList_callback and
pullup_replace_vars_callback are both used to replace Vars in an
expression tree that reference a particular RTE with items from a
targetlist, and they both need to expand whole-tuple reference and
deal with OLD/NEW RETURNING list Vars.  As a result, currently there
is significant code duplication between these two functions.

This patch introduces a new function, ReplaceVarFromTargetList, to
perform the replacement and calls it from both callback functions,
thereby eliminating code duplication.
---
 src/backend/optimizer/prep/prepjointree.c | 137 ++++------------------
 src/backend/rewrite/rewriteManip.c        |  81 +++++++++----
 src/include/rewrite/rewriteManip.h        |   9 +-
 3 files changed, 90 insertions(+), 137 deletions(-)

diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 89b1ff2db87..b41f1698553 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -2660,127 +2660,38 @@ pullup_replace_vars_callback(Var *var,
 		/* Just copy the entry and fall through to adjust phlevelsup etc */
 		newnode = copyObject(rcon->rv_cache[varattno]);
 	}
-	else if (varattno == InvalidAttrNumber)
+	else
 	{
-		/* Must expand whole-tuple reference into RowExpr */
-		RowExpr    *rowexpr;
-		List	   *colnames;
-		List	   *fields;
-		bool		save_wrap_non_vars = rcon->wrap_non_vars;
-		int			save_sublevelsup = context->sublevels_up;
-
-		/*
-		 * If generating an expansion for a var of a named rowtype (ie, this
-		 * is a plain relation RTE), then we must include dummy items for
-		 * dropped columns.  If the var is RECORD (ie, this is a JOIN), then
-		 * omit dropped columns.  In the latter case, attach column names to
-		 * the RowExpr for use of the executor and ruleutils.c.
-		 *
-		 * In order to be able to cache the results, we always generate the
-		 * expansion with varlevelsup = 0, and then adjust below if needed.
-		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, 0 /* not varlevelsup */ ,
-				  var->varreturningtype, var->location,
-				  (var->vartype != RECORDOID),
-				  &colnames, &fields);
-		/* Expand the generated per-field Vars, but don't insert PHVs there */
-		rcon->wrap_non_vars = false;
-		context->sublevels_up = 0;	/* to match the expandRTE output */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
-		rcon->wrap_non_vars = save_wrap_non_vars;
-		context->sublevels_up = save_sublevelsup;
-
-		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
-		rowexpr->row_typeid = var->vartype;
-		rowexpr->row_format = COERCE_IMPLICIT_CAST;
-		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
-		rowexpr->location = var->location;
-		newnode = (Node *) rowexpr;
-
-		/* Handle any OLD/NEW RETURNING list Vars */
-		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
-		{
-			ReturningExpr *rexpr = makeNode(ReturningExpr);
-
-			rexpr->retlevelsup = 0;
-			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
-			rexpr->retexpr = (Expr *) newnode;
-
-			newnode = (Node *) rexpr;
-		}
-
 		/*
-		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
-		 * PlaceHolderVar around the whole RowExpr, rather than putting one
-		 * around each element of the row.  This is because we need the
-		 * expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
-		 * to null by an outer join.
+		 * Generate the replacement expression.  This takes care of expanding
+		 * wholerow references and dealing with non-default varreturningtype.
 		 */
-		if (need_phv)
-		{
-			newnode = (Node *)
-				make_placeholder_expr(rcon->root,
-									  (Expr *) newnode,
-									  bms_make_singleton(rcon->varno));
-			/* cache it with the PHV, and with phlevelsup etc not set yet */
-			rcon->rv_cache[InvalidAttrNumber] = copyObject(newnode);
-		}
-	}
-	else
-	{
-		/* Normal case referencing one targetlist element */
-		TargetEntry *tle = get_tle_by_resno(rcon->targetlist, varattno);
-
-		if (tle == NULL)		/* shouldn't happen */
-			elog(ERROR, "could not find attribute %d in subquery targetlist",
-				 varattno);
-
-		/* Make a copy of the tlist item to return */
-		newnode = (Node *) copyObject(tle->expr);
-
-		/* Handle any OLD/NEW RETURNING list Vars */
-		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
-		{
-			/*
-			 * Copy varreturningtype onto any Vars in the tlist item that
-			 * refer to result_relation (which had better be non-zero).
-			 */
-			if (rcon->result_relation == 0)
-				elog(ERROR, "variable returning old/new found outside RETURNING list");
-
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
-								0, var->varreturningtype);
-
-			/*
-			 * If the replacement expression in the targetlist is not simply a
-			 * Var referencing result_relation, wrap it in a ReturningExpr
-			 * node, so that the executor returns NULL if the OLD/NEW row does
-			 * not exist.
-			 */
-			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
-				((Var *) newnode)->varlevelsup != var->varlevelsup)
-			{
-				ReturningExpr *rexpr = makeNode(ReturningExpr);
-
-				rexpr->retlevelsup = 0;
-				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
-				rexpr->retexpr = (Expr *) newnode;
-
-				newnode = (Node *) rexpr;
-			}
-		}
+		newnode = ReplaceVarFromTargetList(var,
+										   rcon->target_rte,
+										   rcon->targetlist,
+										   rcon->result_relation,
+										   REPLACEVARS_REPORT_ERROR,
+										   0);
 
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
 			bool		wrap;
 
-			if (newnode && IsA(newnode, Var) &&
-				((Var *) newnode)->varlevelsup == 0)
+			if (varattno == InvalidAttrNumber)
+			{
+				/*
+				 * Insert PlaceHolderVar for whole-tuple reference.  Notice
+				 * that we are wrapping one PlaceHolderVar around the whole
+				 * RowExpr, rather than putting one around each element of the
+				 * row.  This is because we need the expression to yield NULL,
+				 * not ROW(NULL,NULL,...) when it is forced to null by an
+				 * outer join.
+				 */
+				wrap = true;
+			}
+			else if (newnode && IsA(newnode, Var) &&
+					 ((Var *) newnode)->varlevelsup == 0)
 			{
 				/*
 				 * Simple Vars always escape being wrapped, unless they are
@@ -2926,7 +2837,7 @@ pullup_replace_vars_callback(Var *var,
 				 * Cache it if possible (ie, if the attno is in range, which
 				 * it probably always should be).
 				 */
-				if (varattno > InvalidAttrNumber &&
+				if (varattno >= InvalidAttrNumber &&
 					varattno <= list_length(rcon->targetlist))
 					rcon->rv_cache[varattno] = copyObject(newnode);
 			}
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 6994b8c5425..dfdd5eec66b 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1010,7 +1010,7 @@ SetVarReturningType_walker(Node *node, SetVarReturningType_context *context)
 	return expression_tree_walker(node, SetVarReturningType_walker, context);
 }
 
-void
+static void
 SetVarReturningType(Node *node, int result_relation, int sublevels_up,
 					VarReturningType returning_type)
 {
@@ -1814,6 +1814,30 @@ ReplaceVarsFromTargetList_callback(Var *var,
 								   replace_rte_variables_context *context)
 {
 	ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
+	Node	   *newnode;
+
+	newnode = ReplaceVarFromTargetList(var,
+									   rcon->target_rte,
+									   rcon->targetlist,
+									   rcon->result_relation,
+									   rcon->nomatch_option,
+									   rcon->nomatch_varno);
+
+	/* Must adjust varlevelsup if replaced Var is within a subquery */
+	if (var->varlevelsup > 0)
+		IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
+
+	return newnode;
+}
+
+Node *
+ReplaceVarFromTargetList(Var *var,
+						 RangeTblEntry *target_rte,
+						 List *targetlist,
+						 int result_relation,
+						 ReplaceVarsNoMatchOption nomatch_option,
+						 int nomatch_varno)
+{
 	TargetEntry *tle;
 
 	if (var->varattno == InvalidAttrNumber)
@@ -1822,6 +1846,7 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		RowExpr    *rowexpr;
 		List	   *colnames;
 		List	   *fields;
+		ListCell   *lc;
 
 		/*
 		 * If generating an expansion for a var of a named rowtype (ie, this
@@ -1830,29 +1855,46 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		 * omit dropped columns.  In the latter case, attach column names to
 		 * the RowExpr for use of the executor and ruleutils.c.
 		 *
+		 * In order to be able to cache the results, we always generate the
+		 * expansion with varlevelsup = 0.  The caller is responsible for
+		 * adjusting it if needed.
+		 *
 		 * The varreturningtype is copied onto each individual field Var, so
 		 * that it is handled correctly when we recurse.
 		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, var->varlevelsup, var->varreturningtype,
-				  var->location, (var->vartype != RECORDOID),
+		expandRTE(target_rte,
+				  var->varno, 0 /* not varlevelsup */ ,
+				  var->varreturningtype, var->location,
+				  (var->vartype != RECORDOID),
 				  &colnames, &fields);
-		/* Adjust the generated per-field Vars... */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
 		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
+		/* the fields will be set below */
+		rowexpr->args = NIL;
 		rowexpr->row_typeid = var->vartype;
 		rowexpr->row_format = COERCE_IMPLICIT_CAST;
 		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
 		rowexpr->location = var->location;
+		/* Adjust the generated per-field Vars... */
+		foreach(lc, fields)
+		{
+			Node	   *field = lfirst(lc);
+
+			if (field && IsA(field, Var))
+				field = ReplaceVarFromTargetList((Var *) field,
+												 target_rte,
+												 targetlist,
+												 result_relation,
+												 nomatch_option,
+												 nomatch_varno);
+			rowexpr->args = lappend(rowexpr->args, field);
+		}
 
 		/* Wrap it in a ReturningExpr, if needed, per comments above */
 		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
 		{
 			ReturningExpr *rexpr = makeNode(ReturningExpr);
 
-			rexpr->retlevelsup = var->varlevelsup;
+			rexpr->retlevelsup = 0;
 			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
 			rexpr->retexpr = (Expr *) rowexpr;
 
@@ -1863,12 +1905,12 @@ ReplaceVarsFromTargetList_callback(Var *var,
 	}
 
 	/* Normal case referencing one targetlist element */
-	tle = get_tle_by_resno(rcon->targetlist, var->varattno);
+	tle = get_tle_by_resno(targetlist, var->varattno);
 
 	if (tle == NULL || tle->resjunk)
 	{
 		/* Failed to find column in targetlist */
-		switch (rcon->nomatch_option)
+		switch (nomatch_option)
 		{
 			case REPLACEVARS_REPORT_ERROR:
 				/* fall through, throw error below */
@@ -1876,7 +1918,8 @@ ReplaceVarsFromTargetList_callback(Var *var,
 
 			case REPLACEVARS_CHANGE_VARNO:
 				var = copyObject(var);
-				var->varno = rcon->nomatch_varno;
+				var->varno = nomatch_varno;
+				var->varlevelsup = 0;
 				/* we leave the syntactic referent alone */
 				return (Node *) var;
 
@@ -1906,10 +1949,6 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		/* Make a copy of the tlist item to return */
 		Expr	   *newnode = copyObject(tle->expr);
 
-		/* Must adjust varlevelsup if tlist item is from higher query */
-		if (var->varlevelsup > 0)
-			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
-
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
@@ -1932,20 +1971,20 @@ ReplaceVarsFromTargetList_callback(Var *var,
 			 * Copy varreturningtype onto any Vars in the tlist item that
 			 * refer to result_relation (which had better be non-zero).
 			 */
-			if (rcon->result_relation == 0)
+			if (result_relation == 0)
 				elog(ERROR, "variable returning old/new found outside RETURNING list");
 
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
-								var->varlevelsup, var->varreturningtype);
+			SetVarReturningType((Node *) newnode, result_relation,
+								0, var->varreturningtype);
 
 			/* Wrap it in a ReturningExpr, if needed, per comments above */
 			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varno != result_relation ||
 				((Var *) newnode)->varlevelsup != var->varlevelsup)
 			{
 				ReturningExpr *rexpr = makeNode(ReturningExpr);
 
-				rexpr->retlevelsup = var->varlevelsup;
+				rexpr->retlevelsup = 0;
 				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
 				rexpr->retexpr = newnode;
 
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 466edd7c1c2..ea3908739c6 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -55,9 +55,6 @@ extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
-extern void SetVarReturningType(Node *node, int result_relation, int sublevels_up,
-								VarReturningType returning_type);
-
 extern bool rangeTableEntry_used(Node *node, int rt_index,
 								 int sublevels_up);
 
@@ -92,6 +89,12 @@ extern Node *map_variable_attnos(Node *node,
 								 const struct AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
+extern Node *ReplaceVarFromTargetList(Var *var,
+									  RangeTblEntry *target_rte,
+									  List *targetlist,
+									  int result_relation,
+									  ReplaceVarsNoMatchOption nomatch_option,
+									  int nomatch_varno);
 extern Node *ReplaceVarsFromTargetList(Node *node,
 									   int target_varno, int sublevels_up,
 									   RangeTblEntry *target_rte,
-- 
2.43.0

From c7b65fa591ea2d7bd7bacf823f20650915fff089 Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Fri, 21 Feb 2025 09:46:59 +0900
Subject: [PATCH v6 1/2] Expand virtual generated columns in the planner

Commit 83ea6c540 added support for virtual generated columns, which
were expanded in the rewriter, in a similar way to view columns.
However, this approach has several issues.  If a Var referencing a
virtual generated column has any varnullingrels, there would be no way
to propagate the varnullingrels into the generation expression,
leading to "wrong varnullingrels" errors and improper outer-join
removal.  Additionally, if such a Var comes from the nullable side of
an outer join, we may need to wrap the generation expression in a
PlaceHolderVar to ensure that it is evaluated at the right place and
hence is forced to null when the outer join should do so.  In some
cases, such as when the query uses grouping sets, we also need a
PlaceHolderVar for anything that's not a simple Var to isolate
subexpressions.  All of this cannot be achieved in the rewriter.

To fix this, the patch expands the virtual generated columns in the
planner and leverages the pullup_replace_vars architecture to avoid
code duplication.  This requires handling the OLD/NEW RETURNING list
Vars in pullup_replace_vars_callback.
---
 src/backend/optimizer/plan/planner.c          |   7 +
 src/backend/optimizer/prep/prepjointree.c     | 186 ++++++++++++++++++
 src/backend/rewrite/rewriteHandler.c          |  91 ++++-----
 src/backend/rewrite/rewriteManip.c            |   2 +-
 src/include/optimizer/prep.h                  |   1 +
 src/include/rewrite/rewriteHandler.h          |   1 +
 src/include/rewrite/rewriteManip.h            |   3 +
 .../regress/expected/generated_virtual.out    |  89 +++++++++
 src/test/regress/sql/generated_virtual.sql    |  38 ++++
 9 files changed, 372 insertions(+), 46 deletions(-)

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 7b1a8a0a9f1..201487eaf42 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -717,6 +717,13 @@ subquery_planner(PlannerGlobal *glob, Query *parse, PlannerInfo *parent_root,
 	 */
 	replace_empty_jointree(parse);
 
+	/*
+	 * Scan the rangetable for relations with virtual generated columns, and
+	 * replace all Var nodes in the query that reference these columns with
+	 * the generation expressions.
+	 */
+	parse = root->parse = expand_virtual_generated_columns(root);
+
 	/*
 	 * Look for ANY and EXISTS SubLinks in WHERE and JOIN/ON clauses, and try
 	 * to transform them into joins.  Note that this step does not descend
diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 5d9225e9909..3125567846f 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -5,6 +5,7 @@
  *
  * NOTE: the intended sequence for invoking these operations is
  *		replace_empty_jointree
+ *		expand_virtual_generated_columns
  *		pull_up_sublinks
  *		preprocess_function_rtes
  *		pull_up_subqueries
@@ -25,6 +26,7 @@
  */
 #include "postgres.h"
 
+#include "access/table.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
@@ -39,7 +41,9 @@
 #include "optimizer/tlist.h"
 #include "parser/parse_relation.h"
 #include "parser/parsetree.h"
+#include "rewrite/rewriteHandler.h"
 #include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
 
 
 typedef struct nullingrel_info
@@ -57,6 +61,7 @@ typedef struct pullup_replace_vars_context
 {
 	PlannerInfo *root;
 	List	   *targetlist;		/* tlist of subquery being pulled up */
+	int			result_relation;
 	RangeTblEntry *target_rte;	/* RTE of subquery */
 	Relids		relids;			/* relids within subquery, as numbered after
 								 * pullup (set only if target_rte->lateral) */
@@ -421,6 +426,128 @@ replace_empty_jointree(Query *parse)
 	parse->jointree->fromlist = list_make1(rtr);
 }
 
+/*
+ * expand_virtual_generated_columns
+ *		Expand all virtual generated column references in a query.
+ *
+ * This scans the rangetable for relations with virtual generated columns, and
+ * replaces all Var nodes in the query that reference these columns with the
+ * appropriate expressions.  Note that we do not recurse into subqueries; that
+ * is taken care of when the subqueries are planned.
+ *
+ * Returns a modified copy of the query tree, if any relations with virtual
+ * generated columns are present.
+ */
+Query *
+expand_virtual_generated_columns(PlannerInfo *root)
+{
+	Query	   *parse = root->parse;
+	int			rt_index;
+	ListCell   *lc;
+
+	rt_index = 0;
+	foreach(lc, parse->rtable)
+	{
+		RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+		Relation	rel;
+		TupleDesc	tupdesc;
+
+		++rt_index;
+
+		/*
+		 * Only normal relations can have virtual generated columns.
+		 */
+		if (rte->rtekind != RTE_RELATION)
+			continue;
+
+		rel = table_open(rte->relid, NoLock);
+
+		tupdesc = RelationGetDescr(rel);
+		if (tupdesc->constr && tupdesc->constr->has_generated_virtual)
+		{
+			List	   *tlist = NIL;
+			pullup_replace_vars_context rvcontext;
+
+			for (int i = 0; i < tupdesc->natts; i++)
+			{
+				Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
+				TargetEntry *tle;
+
+				if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
+				{
+					Node	   *defexpr = build_generation_expression(rel, i + 1);
+
+					ChangeVarNodes(defexpr, 1, rt_index, 0);
+
+					tle = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
+					tlist = lappend(tlist, tle);
+				}
+				else
+				{
+					Var		   *var;
+
+					var = makeVar(rt_index,
+								  i + 1,
+								  attr->atttypid,
+								  attr->atttypmod,
+								  attr->attcollation,
+								  0);
+
+					tle = makeTargetEntry((Expr *) var, i + 1, 0, false);
+					tlist = lappend(tlist, tle);
+				}
+			}
+
+			Assert(list_length(tlist) > 0);
+			Assert(!rte->lateral);
+
+			/*
+			 * The relation's targetlist items are now in the appropriate form
+			 * to insert into the query, except that we may need to wrap them
+			 * in PlaceHolderVars.  Set up required context data for
+			 * pullup_replace_vars.
+			 */
+			rvcontext.root = root;
+			rvcontext.targetlist = tlist;
+			rvcontext.result_relation = parse->resultRelation;
+			rvcontext.target_rte = rte;
+			/* won't need these values */
+			rvcontext.relids = NULL;
+			rvcontext.nullinfo = NULL;
+			/* pass NULL for outer_hasSubLinks */
+			rvcontext.outer_hasSubLinks = NULL;
+			rvcontext.varno = rt_index;
+			/* this flag will be set below, if needed */
+			rvcontext.wrap_non_vars = false;
+			/* initialize cache array with indexes 0 .. length(tlist) */
+			rvcontext.rv_cache = palloc0((list_length(tlist) + 1) *
+										 sizeof(Node *));
+
+			/*
+			 * If the query uses grouping sets, we need a PlaceHolderVar for
+			 * anything that's not a simple Var.  This ensures that
+			 * expressions retain their separate identity so that they will
+			 * match grouping set columns when appropriate.  (It'd be
+			 * sufficient to wrap values used in grouping set columns, and do
+			 * so only in non-aggregated portions of the tlist and havingQual,
+			 * but that would require a lot of infrastructure that
+			 * pullup_replace_vars hasn't currently got.)
+			 */
+			if (parse->groupingSets)
+				rvcontext.wrap_non_vars = true;
+
+			/*
+			 * Apply pullup variable replacement throughout the query tree.
+			 */
+			parse = (Query *) pullup_replace_vars((Node *) parse, &rvcontext);
+		}
+
+		table_close(rel, NoLock);
+	}
+
+	return parse;
+}
+
 /*
  * pull_up_sublinks
  *		Attempt to pull up ANY and EXISTS SubLinks to be treated as
@@ -1184,6 +1311,13 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	replace_empty_jointree(subquery);
 
+	/*
+	 * Scan the rangetable for relations with virtual generated columns, and
+	 * replace all Var nodes in the query that reference these columns with
+	 * the generation expressions.
+	 */
+	subquery = subroot->parse = expand_virtual_generated_columns(subroot);
+
 	/*
 	 * Pull up any SubLinks within the subquery's quals, so that we don't
 	 * leave unoptimized SubLinks behind.
@@ -1273,6 +1407,7 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
 	 */
 	rvcontext.root = root;
 	rvcontext.targetlist = subquery->targetList;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	if (rte->lateral)
 	{
@@ -1833,6 +1968,7 @@ pull_up_simple_values(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte)
 	}
 	rvcontext.root = root;
 	rvcontext.targetlist = tlist;
+	rvcontext.result_relation = 0;
 	rvcontext.target_rte = rte;
 	rvcontext.relids = NULL;	/* can't be any lateral references here */
 	rvcontext.nullinfo = NULL;
@@ -1993,6 +2129,7 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode,
 													  NULL, /* resname */
 													  false));	/* resjunk */
 	rvcontext.target_rte = rte;
+	rvcontext.result_relation = 0;
 
 	/*
 	 * Since this function was reduced to a Const, it doesn't contain any
@@ -2490,6 +2627,10 @@ pullup_replace_vars_callback(Var *var,
 	bool		need_phv;
 	Node	   *newnode;
 
+	/* System columns are not replaced. */
+	if (varattno < InvalidAttrNumber)
+		return (Node *) copyObject(var);
+
 	/*
 	 * We need a PlaceHolderVar if the Var-to-be-replaced has nonempty
 	 * varnullingrels (unless we find below that the replacement expression is
@@ -2559,6 +2700,18 @@ pullup_replace_vars_callback(Var *var,
 		rowexpr->location = var->location;
 		newnode = (Node *) rowexpr;
 
+		/* Handle any OLD/NEW RETURNING list Vars */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+			rexpr->retlevelsup = 0;
+			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+			rexpr->retexpr = (Expr *) newnode;
+
+			newnode = (Node *) rexpr;
+		}
+
 		/*
 		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
 		 * PlaceHolderVar around the whole RowExpr, rather than putting one
@@ -2588,6 +2741,39 @@ pullup_replace_vars_callback(Var *var,
 		/* Make a copy of the tlist item to return */
 		newnode = (Node *) copyObject(tle->expr);
 
+		/* Handle any OLD/NEW RETURNING list Vars */
+		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
+		{
+			/*
+			 * Copy varreturningtype onto any Vars in the tlist item that
+			 * refer to result_relation (which had better be non-zero).
+			 */
+			if (rcon->result_relation == 0)
+				elog(ERROR, "variable returning old/new found outside RETURNING list");
+
+			SetVarReturningType((Node *) newnode, rcon->result_relation,
+								0, var->varreturningtype);
+
+			/*
+			 * If the replacement expression in the targetlist is not simply a
+			 * Var referencing result_relation, wrap it in a ReturningExpr
+			 * node, so that the executor returns NULL if the OLD/NEW row does
+			 * not exist.
+			 */
+			if (!IsA(newnode, Var) ||
+				((Var *) newnode)->varno != rcon->result_relation ||
+				((Var *) newnode)->varlevelsup != 0)
+			{
+				ReturningExpr *rexpr = makeNode(ReturningExpr);
+
+				rexpr->retlevelsup = 0;
+				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
+				rexpr->retexpr = (Expr *) newnode;
+
+				newnode = (Node *) rexpr;
+			}
+		}
+
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index e996bdc0d21..1fa9f8cc55f 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -2190,10 +2190,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 	 * requires special recursion detection if the new quals have sublink
 	 * subqueries, and if we did it in the loop above query_tree_walker would
 	 * then recurse into those quals a second time.
-	 *
-	 * Finally, we expand any virtual generated columns.  We do this after
-	 * each table's RLS policies are applied because the RLS policies might
-	 * also refer to the table's virtual generated columns.
 	 */
 	rt_index = 0;
 	foreach(lc, parsetree->rtable)
@@ -2207,11 +2203,10 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 
 		++rt_index;
 
-		/*
-		 * Only normal relations can have RLS policies or virtual generated
-		 * columns.
-		 */
-		if (rte->rtekind != RTE_RELATION)
+		/* Only normal relations can have RLS policies */
+		if (rte->rtekind != RTE_RELATION ||
+			(rte->relkind != RELKIND_RELATION &&
+			 rte->relkind != RELKIND_PARTITIONED_TABLE))
 			continue;
 
 		rel = table_open(rte->relid, NoLock);
@@ -2300,16 +2295,6 @@ fireRIRrules(Query *parsetree, List *activeRIRs)
 		if (hasSubLinks)
 			parsetree->hasSubLinks = true;
 
-		/*
-		 * Expand any references to virtual generated columns of this table.
-		 * Note that subqueries in virtual generated column expressions are
-		 * not currently supported, so this cannot add any more sublinks.
-		 */
-		parsetree = (Query *)
-			expand_generated_columns_internal((Node *) parsetree,
-											  rel, rt_index, rte,
-											  parsetree->resultRelation);
-
 		table_close(rel, NoLock);
 	}
 
@@ -4456,36 +4441,12 @@ expand_generated_columns_internal(Node *node, Relation rel, int rt_index,
 
 			if (attr->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
 			{
-				Node	   *defexpr;
-				int			attnum = i + 1;
-				Oid			attcollid;
 				TargetEntry *te;
-
-				defexpr = build_column_default(rel, attnum);
-				if (defexpr == NULL)
-					elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
-						 attnum, RelationGetRelationName(rel));
-
-				/*
-				 * If the column definition has a collation and it is
-				 * different from the collation of the generation expression,
-				 * put a COLLATE clause around the expression.
-				 */
-				attcollid = attr->attcollation;
-				if (attcollid && attcollid != exprCollation(defexpr))
-				{
-					CollateExpr *ce = makeNode(CollateExpr);
-
-					ce->arg = (Expr *) defexpr;
-					ce->collOid = attcollid;
-					ce->location = -1;
-
-					defexpr = (Node *) ce;
-				}
+				Node	   *defexpr = build_generation_expression(rel, i + 1);
 
 				ChangeVarNodes(defexpr, 1, rt_index, 0);
 
-				te = makeTargetEntry((Expr *) defexpr, attnum, 0, false);
+				te = makeTargetEntry((Expr *) defexpr, i + 1, 0, false);
 				tlist = lappend(tlist, te);
 			}
 		}
@@ -4528,6 +4489,46 @@ expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index)
 	return node;
 }
 
+/*
+ * Build the generation expression for the virtual generated column.
+ *
+ * Error out if there is no generation expression found for the given column.
+ */
+Node *
+build_generation_expression(Relation rel, int attrno)
+{
+	TupleDesc	rd_att = RelationGetDescr(rel);
+	Form_pg_attribute att_tup = TupleDescAttr(rd_att, attrno - 1);
+	Node	   *defexpr;
+	Oid			attcollid;
+
+	Assert(att_tup->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL);
+
+	defexpr = build_column_default(rel, attrno);
+	if (defexpr == NULL)
+		elog(ERROR, "no generation expression found for column number %d of table \"%s\"",
+			 attrno, RelationGetRelationName(rel));
+
+	/*
+	 * If the column definition has a collation and it is different from the
+	 * collation of the generation expression, put a COLLATE clause around the
+	 * expression.
+	 */
+	attcollid = att_tup->attcollation;
+	if (attcollid && attcollid != exprCollation(defexpr))
+	{
+		CollateExpr *ce = makeNode(CollateExpr);
+
+		ce->arg = (Expr *) defexpr;
+		ce->collOid = attcollid;
+		ce->location = -1;
+
+		defexpr = (Node *) ce;
+	}
+
+	return defexpr;
+}
+
 
 /*
  * QueryRewrite -
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 9433548d279..6994b8c5425 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1010,7 +1010,7 @@ SetVarReturningType_walker(Node *node, SetVarReturningType_context *context)
 	return expression_tree_walker(node, SetVarReturningType_walker, context);
 }
 
-static void
+void
 SetVarReturningType(Node *node, int result_relation, int sublevels_up,
 					VarReturningType returning_type)
 {
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 0ae57ec24a4..0a61cd126b7 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -23,6 +23,7 @@
  */
 extern void transform_MERGE_to_join(Query *parse);
 extern void replace_empty_jointree(Query *parse);
+extern Query *expand_virtual_generated_columns(PlannerInfo *root);
 extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
 extern void pull_up_subqueries(PlannerInfo *root);
diff --git a/src/include/rewrite/rewriteHandler.h b/src/include/rewrite/rewriteHandler.h
index 88fe13c5f4f..99cab1a3bfa 100644
--- a/src/include/rewrite/rewriteHandler.h
+++ b/src/include/rewrite/rewriteHandler.h
@@ -39,5 +39,6 @@ extern void error_view_not_updatable(Relation view,
 									 const char *detail);
 
 extern Node *expand_generated_columns_in_expr(Node *node, Relation rel, int rt_index);
+extern Node *build_generation_expression(Relation rel, int attrno);
 
 #endif							/* REWRITEHANDLER_H */
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 5ec475c63e9..466edd7c1c2 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -55,6 +55,9 @@ extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
+extern void SetVarReturningType(Node *node, int result_relation, int sublevels_up,
+								VarReturningType returning_type);
+
 extern bool rangeTableEntry_used(Node *node, int rt_index,
 								 int sublevels_up);
 
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 35638812be9..cb2383469c6 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -1398,3 +1398,92 @@ SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT
 ----------+---------+--------------
 (0 rows)
 
+--
+-- test the expansion of virtual generated columns
+--
+create table gtest32 (
+  a int,
+  b int generated always as (a * 2),
+  c int generated always as (10 + 10),
+  d int generated always as (coalesce(a, 100))
+);
+insert into gtest32 values (1), (2);
+-- Ensure that nullingrel bits are propagated into the generation expression
+explain (costs off)
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+                      QUERY PLAN                      
+------------------------------------------------------
+ Sort
+   Sort Key: t1.a
+   ->  WindowAgg
+         ->  Sort
+               Sort Key: t2.a
+               ->  Merge Left Join
+                     Merge Cond: (t1.a = t2.a)
+                     ->  Sort
+                           Sort Key: t1.a
+                           ->  Seq Scan on gtest32 t1
+                     ->  Sort
+                           Sort Key: t2.a
+                           ->  Seq Scan on gtest32 t2
+(13 rows)
+
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+ sum | sum | sum 
+-----+-----+-----
+   2 |  20 |   1
+   4 |  20 |   2
+(2 rows)
+
+-- Ensure that the generation expressions are wrapped into PHVs if needed
+explain (verbose, costs off)
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+                      QUERY PLAN                      
+------------------------------------------------------
+ Nested Loop Left Join
+   Output: a, (a * 2), (20), (COALESCE(a, 100))
+   Join Filter: false
+   ->  Seq Scan on generated_virtual_tests.gtest32 t1
+         Output: t1.a, t1.b, t1.c, t1.d
+   ->  Result
+         Output: a, 20, COALESCE(a, 100)
+         One-Time Filter: false
+(8 rows)
+
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+ a | b | c | d 
+---+---+---+---
+   |   |   |  
+   |   |   |  
+(2 rows)
+
+explain (verbose, costs off)
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+                     QUERY PLAN                      
+-----------------------------------------------------
+ HashAggregate
+   Output: a, ((a * 2)), (20), (COALESCE(a, 100))
+   Hash Key: t.a
+   Hash Key: (t.a * 2)
+   Hash Key: 20
+   Hash Key: COALESCE(t.a, 100)
+   Filter: ((20) = 20)
+   ->  Seq Scan on generated_virtual_tests.gtest32 t
+         Output: a, (a * 2), 20, COALESCE(a, 100)
+(9 rows)
+
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+ a | b | c  | d 
+---+---+----+---
+   |   | 20 |  
+(1 row)
+
+drop table gtest32;
diff --git a/src/test/regress/sql/generated_virtual.sql b/src/test/regress/sql/generated_virtual.sql
index 34870813910..25b28a83b1b 100644
--- a/src/test/regress/sql/generated_virtual.sql
+++ b/src/test/regress/sql/generated_virtual.sql
@@ -732,3 +732,41 @@ CREATE TABLE gtest28b (LIKE gtest28a INCLUDING GENERATED);
 
 -- sanity check of system catalog
 SELECT attrelid, attname, attgenerated FROM pg_attribute WHERE attgenerated NOT IN ('', 's', 'v');
+
+--
+-- test the expansion of virtual generated columns
+--
+
+create table gtest32 (
+  a int,
+  b int generated always as (a * 2),
+  c int generated always as (10 + 10),
+  d int generated always as (coalesce(a, 100))
+);
+
+insert into gtest32 values (1), (2);
+
+-- Ensure that nullingrel bits are propagated into the generation expression
+explain (costs off)
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+
+select sum(t2.b) over (partition by t2.a),
+       sum(t2.c) over (partition by t2.a),
+       sum(t2.d) over (partition by t2.a)
+from gtest32 as t1 left join gtest32 as t2 on (t1.a = t2.a)
+order by t1.a;
+
+-- Ensure that the generation expressions are wrapped into PHVs if needed
+explain (verbose, costs off)
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+select t2.* from gtest32 t1 left join gtest32 t2 on false;
+
+explain (verbose, costs off)
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+select * from gtest32 t group by grouping sets (a, b, c, d) having c = 20;
+
+drop table gtest32;
-- 
2.43.0

From 4643a1832ba30c5c6ddee4643676045675f65e28 Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Fri, 21 Feb 2025 14:01:56 +0900
Subject: [PATCH v6 2/2] Eliminate code duplication in replace_rte_variables
 callbacks

The callback functions ReplaceVarsFromTargetList_callback and
pullup_replace_vars_callback are both used to replace Vars in an
expression tree that reference a particular RTE with items from a
targetlist, and they both need to expand whole-tuple reference and
deal with OLD/NEW RETURNING list Vars.  As a result, currently there
is significant code duplication between these two functions.

This patch introduces a new function, ReplaceVarFromTargetList, to
perform the replacement and calls it from both callback functions,
thereby eliminating code duplication.
---
 src/backend/optimizer/prep/prepjointree.c | 137 ++++------------------
 src/backend/rewrite/rewriteManip.c        |  83 +++++++++----
 src/include/rewrite/rewriteManip.h        |   9 +-
 3 files changed, 91 insertions(+), 138 deletions(-)

diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c
index 3125567846f..367404735b8 100644
--- a/src/backend/optimizer/prep/prepjointree.c
+++ b/src/backend/optimizer/prep/prepjointree.c
@@ -2660,127 +2660,38 @@ pullup_replace_vars_callback(Var *var,
 		/* Just copy the entry and fall through to adjust phlevelsup etc */
 		newnode = copyObject(rcon->rv_cache[varattno]);
 	}
-	else if (varattno == InvalidAttrNumber)
+	else
 	{
-		/* Must expand whole-tuple reference into RowExpr */
-		RowExpr    *rowexpr;
-		List	   *colnames;
-		List	   *fields;
-		bool		save_wrap_non_vars = rcon->wrap_non_vars;
-		int			save_sublevelsup = context->sublevels_up;
-
-		/*
-		 * If generating an expansion for a var of a named rowtype (ie, this
-		 * is a plain relation RTE), then we must include dummy items for
-		 * dropped columns.  If the var is RECORD (ie, this is a JOIN), then
-		 * omit dropped columns.  In the latter case, attach column names to
-		 * the RowExpr for use of the executor and ruleutils.c.
-		 *
-		 * In order to be able to cache the results, we always generate the
-		 * expansion with varlevelsup = 0, and then adjust below if needed.
-		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, 0 /* not varlevelsup */ ,
-				  var->varreturningtype, var->location,
-				  (var->vartype != RECORDOID),
-				  &colnames, &fields);
-		/* Expand the generated per-field Vars, but don't insert PHVs there */
-		rcon->wrap_non_vars = false;
-		context->sublevels_up = 0;	/* to match the expandRTE output */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
-		rcon->wrap_non_vars = save_wrap_non_vars;
-		context->sublevels_up = save_sublevelsup;
-
-		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
-		rowexpr->row_typeid = var->vartype;
-		rowexpr->row_format = COERCE_IMPLICIT_CAST;
-		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
-		rowexpr->location = var->location;
-		newnode = (Node *) rowexpr;
-
-		/* Handle any OLD/NEW RETURNING list Vars */
-		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
-		{
-			ReturningExpr *rexpr = makeNode(ReturningExpr);
-
-			rexpr->retlevelsup = 0;
-			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
-			rexpr->retexpr = (Expr *) newnode;
-
-			newnode = (Node *) rexpr;
-		}
-
 		/*
-		 * Insert PlaceHolderVar if needed.  Notice that we are wrapping one
-		 * PlaceHolderVar around the whole RowExpr, rather than putting one
-		 * around each element of the row.  This is because we need the
-		 * expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
-		 * to null by an outer join.
+		 * Generate the replacement expression.  This takes care of expanding
+		 * wholerow references and dealing with non-default varreturningtype.
 		 */
-		if (need_phv)
-		{
-			newnode = (Node *)
-				make_placeholder_expr(rcon->root,
-									  (Expr *) newnode,
-									  bms_make_singleton(rcon->varno));
-			/* cache it with the PHV, and with phlevelsup etc not set yet */
-			rcon->rv_cache[InvalidAttrNumber] = copyObject(newnode);
-		}
-	}
-	else
-	{
-		/* Normal case referencing one targetlist element */
-		TargetEntry *tle = get_tle_by_resno(rcon->targetlist, varattno);
-
-		if (tle == NULL)		/* shouldn't happen */
-			elog(ERROR, "could not find attribute %d in subquery targetlist",
-				 varattno);
-
-		/* Make a copy of the tlist item to return */
-		newnode = (Node *) copyObject(tle->expr);
-
-		/* Handle any OLD/NEW RETURNING list Vars */
-		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
-		{
-			/*
-			 * Copy varreturningtype onto any Vars in the tlist item that
-			 * refer to result_relation (which had better be non-zero).
-			 */
-			if (rcon->result_relation == 0)
-				elog(ERROR, "variable returning old/new found outside RETURNING list");
-
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
-								0, var->varreturningtype);
-
-			/*
-			 * If the replacement expression in the targetlist is not simply a
-			 * Var referencing result_relation, wrap it in a ReturningExpr
-			 * node, so that the executor returns NULL if the OLD/NEW row does
-			 * not exist.
-			 */
-			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
-				((Var *) newnode)->varlevelsup != 0)
-			{
-				ReturningExpr *rexpr = makeNode(ReturningExpr);
-
-				rexpr->retlevelsup = 0;
-				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
-				rexpr->retexpr = (Expr *) newnode;
-
-				newnode = (Node *) rexpr;
-			}
-		}
+		newnode = ReplaceVarFromTargetList(var,
+										   rcon->target_rte,
+										   rcon->targetlist,
+										   rcon->result_relation,
+										   REPLACEVARS_REPORT_ERROR,
+										   0);
 
 		/* Insert PlaceHolderVar if needed */
 		if (need_phv)
 		{
 			bool		wrap;
 
-			if (newnode && IsA(newnode, Var) &&
-				((Var *) newnode)->varlevelsup == 0)
+			if (varattno == InvalidAttrNumber)
+			{
+				/*
+				 * Insert PlaceHolderVar for whole-tuple reference.  Notice
+				 * that we are wrapping one PlaceHolderVar around the whole
+				 * RowExpr, rather than putting one around each element of the
+				 * row.  This is because we need the expression to yield NULL,
+				 * not ROW(NULL,NULL,...) when it is forced to null by an
+				 * outer join.
+				 */
+				wrap = true;
+			}
+			else if (newnode && IsA(newnode, Var) &&
+					 ((Var *) newnode)->varlevelsup == 0)
 			{
 				/*
 				 * Simple Vars always escape being wrapped, unless they are
@@ -2926,7 +2837,7 @@ pullup_replace_vars_callback(Var *var,
 				 * Cache it if possible (ie, if the attno is in range, which
 				 * it probably always should be).
 				 */
-				if (varattno > InvalidAttrNumber &&
+				if (varattno >= InvalidAttrNumber &&
 					varattno <= list_length(rcon->targetlist))
 					rcon->rv_cache[varattno] = copyObject(newnode);
 			}
diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index 6994b8c5425..6e6ea76a664 100644
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -1010,7 +1010,7 @@ SetVarReturningType_walker(Node *node, SetVarReturningType_context *context)
 	return expression_tree_walker(node, SetVarReturningType_walker, context);
 }
 
-void
+static void
 SetVarReturningType(Node *node, int result_relation, int sublevels_up,
 					VarReturningType returning_type)
 {
@@ -1814,6 +1814,30 @@ ReplaceVarsFromTargetList_callback(Var *var,
 								   replace_rte_variables_context *context)
 {
 	ReplaceVarsFromTargetList_context *rcon = (ReplaceVarsFromTargetList_context *) context->callback_arg;
+	Node	   *newnode;
+
+	newnode = ReplaceVarFromTargetList(var,
+									   rcon->target_rte,
+									   rcon->targetlist,
+									   rcon->result_relation,
+									   rcon->nomatch_option,
+									   rcon->nomatch_varno);
+
+	/* Must adjust varlevelsup if replaced Var is within a subquery */
+	if (var->varlevelsup > 0)
+		IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
+
+	return newnode;
+}
+
+Node *
+ReplaceVarFromTargetList(Var *var,
+						 RangeTblEntry *target_rte,
+						 List *targetlist,
+						 int result_relation,
+						 ReplaceVarsNoMatchOption nomatch_option,
+						 int nomatch_varno)
+{
 	TargetEntry *tle;
 
 	if (var->varattno == InvalidAttrNumber)
@@ -1822,6 +1846,7 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		RowExpr    *rowexpr;
 		List	   *colnames;
 		List	   *fields;
+		ListCell   *lc;
 
 		/*
 		 * If generating an expansion for a var of a named rowtype (ie, this
@@ -1830,29 +1855,46 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		 * omit dropped columns.  In the latter case, attach column names to
 		 * the RowExpr for use of the executor and ruleutils.c.
 		 *
+		 * In order to be able to cache the results, we always generate the
+		 * expansion with varlevelsup = 0.  The caller is responsible for
+		 * adjusting it if needed.
+		 *
 		 * The varreturningtype is copied onto each individual field Var, so
 		 * that it is handled correctly when we recurse.
 		 */
-		expandRTE(rcon->target_rte,
-				  var->varno, var->varlevelsup, var->varreturningtype,
-				  var->location, (var->vartype != RECORDOID),
+		expandRTE(target_rte,
+				  var->varno, 0 /* not varlevelsup */ ,
+				  var->varreturningtype, var->location,
+				  (var->vartype != RECORDOID),
 				  &colnames, &fields);
-		/* Adjust the generated per-field Vars... */
-		fields = (List *) replace_rte_variables_mutator((Node *) fields,
-														context);
 		rowexpr = makeNode(RowExpr);
-		rowexpr->args = fields;
+		/* the fields will be set below */
+		rowexpr->args = NIL;
 		rowexpr->row_typeid = var->vartype;
 		rowexpr->row_format = COERCE_IMPLICIT_CAST;
 		rowexpr->colnames = (var->vartype == RECORDOID) ? colnames : NIL;
 		rowexpr->location = var->location;
+		/* Adjust the generated per-field Vars... */
+		foreach(lc, fields)
+		{
+			Node	   *field = lfirst(lc);
+
+			if (field && IsA(field, Var))
+				field = ReplaceVarFromTargetList((Var *) field,
+												 target_rte,
+												 targetlist,
+												 result_relation,
+												 nomatch_option,
+												 nomatch_varno);
+			rowexpr->args = lappend(rowexpr->args, field);
+		}
 
 		/* Wrap it in a ReturningExpr, if needed, per comments above */
 		if (var->varreturningtype != VAR_RETURNING_DEFAULT)
 		{
 			ReturningExpr *rexpr = makeNode(ReturningExpr);
 
-			rexpr->retlevelsup = var->varlevelsup;
+			rexpr->retlevelsup = 0;
 			rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
 			rexpr->retexpr = (Expr *) rowexpr;
 
@@ -1863,12 +1905,12 @@ ReplaceVarsFromTargetList_callback(Var *var,
 	}
 
 	/* Normal case referencing one targetlist element */
-	tle = get_tle_by_resno(rcon->targetlist, var->varattno);
+	tle = get_tle_by_resno(targetlist, var->varattno);
 
 	if (tle == NULL || tle->resjunk)
 	{
 		/* Failed to find column in targetlist */
-		switch (rcon->nomatch_option)
+		switch (nomatch_option)
 		{
 			case REPLACEVARS_REPORT_ERROR:
 				/* fall through, throw error below */
@@ -1876,7 +1918,8 @@ ReplaceVarsFromTargetList_callback(Var *var,
 
 			case REPLACEVARS_CHANGE_VARNO:
 				var = copyObject(var);
-				var->varno = rcon->nomatch_varno;
+				var->varno = nomatch_varno;
+				var->varlevelsup = 0;
 				/* we leave the syntactic referent alone */
 				return (Node *) var;
 
@@ -1906,10 +1949,6 @@ ReplaceVarsFromTargetList_callback(Var *var,
 		/* Make a copy of the tlist item to return */
 		Expr	   *newnode = copyObject(tle->expr);
 
-		/* Must adjust varlevelsup if tlist item is from higher query */
-		if (var->varlevelsup > 0)
-			IncrementVarSublevelsUp((Node *) newnode, var->varlevelsup, 0);
-
 		/*
 		 * Check to see if the tlist item contains a PARAM_MULTIEXPR Param,
 		 * and throw error if so.  This case could only happen when expanding
@@ -1932,20 +1971,20 @@ ReplaceVarsFromTargetList_callback(Var *var,
 			 * Copy varreturningtype onto any Vars in the tlist item that
 			 * refer to result_relation (which had better be non-zero).
 			 */
-			if (rcon->result_relation == 0)
+			if (result_relation == 0)
 				elog(ERROR, "variable returning old/new found outside RETURNING list");
 
-			SetVarReturningType((Node *) newnode, rcon->result_relation,
-								var->varlevelsup, var->varreturningtype);
+			SetVarReturningType((Node *) newnode, result_relation,
+								0, var->varreturningtype);
 
 			/* Wrap it in a ReturningExpr, if needed, per comments above */
 			if (!IsA(newnode, Var) ||
-				((Var *) newnode)->varno != rcon->result_relation ||
-				((Var *) newnode)->varlevelsup != var->varlevelsup)
+				((Var *) newnode)->varno != result_relation ||
+				((Var *) newnode)->varlevelsup != 0)
 			{
 				ReturningExpr *rexpr = makeNode(ReturningExpr);
 
-				rexpr->retlevelsup = var->varlevelsup;
+				rexpr->retlevelsup = 0;
 				rexpr->retold = (var->varreturningtype == VAR_RETURNING_OLD);
 				rexpr->retexpr = newnode;
 
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 466edd7c1c2..ea3908739c6 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.h
@@ -55,9 +55,6 @@ extern void IncrementVarSublevelsUp(Node *node, int delta_sublevels_up,
 extern void IncrementVarSublevelsUp_rtable(List *rtable,
 										   int delta_sublevels_up, int min_sublevels_up);
 
-extern void SetVarReturningType(Node *node, int result_relation, int sublevels_up,
-								VarReturningType returning_type);
-
 extern bool rangeTableEntry_used(Node *node, int rt_index,
 								 int sublevels_up);
 
@@ -92,6 +89,12 @@ extern Node *map_variable_attnos(Node *node,
 								 const struct AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
+extern Node *ReplaceVarFromTargetList(Var *var,
+									  RangeTblEntry *target_rte,
+									  List *targetlist,
+									  int result_relation,
+									  ReplaceVarsNoMatchOption nomatch_option,
+									  int nomatch_varno);
 extern Node *ReplaceVarsFromTargetList(Node *node,
 									   int target_varno, int sublevels_up,
 									   RangeTblEntry *target_rte,
-- 
2.43.0