diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 4e09e06..0879d12 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -1095,6 +1095,17 @@ <title><structname>pg_attribute</> Columns</title>
      </row>
 
      <row>
+      <entry><structfield>attidentity</structfield></entry>
+      <entry><type>char</type></entry>
+      <entry></entry>
+      <entry>
+       If a space character, then not an identity column.  Otherwise,
+       <literal>a</literal> = generated always, <literal>d</literal> =
+       generated by default.
+      </entry>
+     </row>
+
+     <row>
       <entry><structfield>attisdropped</structfield></entry>
       <entry><type>bool</type></entry>
       <entry></entry>
diff --git a/doc/src/sgml/information_schema.sgml b/doc/src/sgml/information_schema.sgml
index c43e325..8ece439 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -1583,13 +1583,20 @@ <title><literal>columns</literal> Columns</title>
      <row>
       <entry><literal>is_identity</literal></entry>
       <entry><type>yes_or_no</type></entry>
-      <entry>Applies to a feature not available in <productname>PostgreSQL</></entry>
+      <entry>
+       If the column is an identity column, then <literal>YES</literal>,
+       else <literal>NO</literal>.
+      </entry>
      </row>
 
      <row>
       <entry><literal>identity_generation</literal></entry>
       <entry><type>character_data</type></entry>
-      <entry>Applies to a feature not available in <productname>PostgreSQL</></entry>
+      <entry>
+       If the column is an identity column, then <literal>ALWAYS</literal>
+       or <literal>BY DEFAULT</literal>, reflecting the definition of the
+       column.
+      </entry>
      </row>
 
      <row>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 6f51cbc..969ce45 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -42,6 +42,8 @@
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> DROP DEFAULT
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> { SET | DROP } NOT NULL
+    ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ]
+    ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> DROP IDENTITY
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET STATISTICS <replaceable class="PARAMETER">integer</replaceable>
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET ( <replaceable class="PARAMETER">attribute_option</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> RESET ( <replaceable class="PARAMETER">attribute_option</replaceable> [, ... ] )
@@ -170,6 +172,15 @@ <title>Description</title>
    </varlistentry>
 
    <varlistentry>
+    <term><literal>ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY</literal>/<literal>DROP IDENTITY</literal></term>
+    <listitem>
+     <para>
+      These forms change whether a column is an identity column.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><literal>SET STATISTICS</literal></term>
     <listitem>
      <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index bf2ad64..408fdca 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -49,6 +49,7 @@
   NULL |
   CHECK ( <replaceable class="PARAMETER">expression</replaceable> ) [ NO INHERIT ] |
   DEFAULT <replaceable>default_expr</replaceable> |
+  GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="PARAMETER">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="PARAMETER">index_parameters</replaceable> |
   REFERENCES <replaceable class="PARAMETER">reftable</replaceable> [ ( <replaceable class="PARAMETER">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
@@ -68,7 +69,7 @@
 
 <phrase>and <replaceable class="PARAMETER">like_option</replaceable> is:</phrase>
 
-{ INCLUDING | EXCLUDING } { DEFAULTS | CONSTRAINTS | INDEXES | STORAGE | COMMENTS | ALL }
+{ INCLUDING | EXCLUDING } { DEFAULTS | CONSTRAINTS | IDENTITY | INDEXES | STORAGE | COMMENTS | ALL }
 
 <phrase><replaceable class="PARAMETER">index_parameters</replaceable> in <literal>UNIQUE</literal>, <literal>PRIMARY KEY</literal>, and <literal>EXCLUDE</literal> constraints are:</phrase>
 
@@ -338,6 +339,12 @@ <title>Parameters</title>
       the original and new tables.
      </para>
      <para>
+      Any identity specifications of copied column definitions will only be
+      copied if <literal>INCLUDING IDENTITY</literal> is specified.  A new
+      sequence is created for each identity column of the new table, separate
+      from the sequences associated with the old table.
+     </para>
+     <para>
       Not-null constraints are always copied to the new table.
       <literal>CHECK</literal> constraints will be copied only if
       <literal>INCLUDING CONSTRAINTS</literal> is specified.
@@ -369,7 +376,7 @@ <title>Parameters</title>
      </para>
      <para>
       <literal>INCLUDING ALL</literal> is an abbreviated form of
-      <literal>INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS</literal>.
+      <literal>INCLUDING DEFAULTS INCLUDING IDENTITY INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS</literal>.
      </para>
      <para>
       Note that unlike <literal>INHERITS</literal>, columns and
@@ -484,6 +491,35 @@ <title>Parameters</title>
    </varlistentry>
 
    <varlistentry>
+    <term><literal>GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ]</literal></term>
+    <listitem>
+     <para>
+      This clause creates the column as an <firstterm>identity
+      column</firstterm>.  It will have an implicit sequence attached to it
+      and the column in new rows will automatically have values from the
+      sequence assigned to it.  This is similar to a default value TODO.
+     </para>
+
+     <para>
+      The clauses <literal>ALWAYS</literal> and <literal>BY DEFAULT</literal>
+      determine how the sequence value is given precedence over a
+      user-specified value in an <command>INSERT</command> statement.
+      If <literal>ALWAYS</literal> is specified, a user-specified value is
+      only accepted if the <command>INSERT</command> statement
+      specifies <literal>OVERRIDING SYSTEM VALUE</literal>.  If <literal>BY
+      DEFAULT</literal> is specified, then the user-specified value takes
+      precedence.  See <xref linkend="sql-insert"> for details.
+     </para>
+
+     <para>
+      The optional <replaceable>sequence_options</replaceable> clause can be
+      used to override the options of the sequence.
+      See <xref linkend="sql-createsequence"> for details.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
     <term><literal>UNIQUE</> (column constraint)</term>
     <term><literal>UNIQUE ( <replaceable class="PARAMETER">column_name</replaceable> [, ... ] )</> (table constraint)</term>
 
@@ -1116,7 +1152,7 @@ <title>Notes</title>
 
     <para>
      Using OIDs in new applications is not recommended: where
-     possible, using a <literal>SERIAL</literal> or other sequence
+     possible, using an identity column or other sequence
      generator as the table's primary key is preferred. However, if
      your application does make use of OIDs to identify specific
      rows of a table, it is recommended to create a unique constraint
@@ -1176,7 +1212,7 @@ <title>Examples</title>
 );
 
 CREATE TABLE distributors (
-     did    integer PRIMARY KEY DEFAULT nextval('serial'),
+     did    integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
      name   varchar(40) NOT NULL CHECK (name &lt;&gt; '')
 );
 </programlisting>
diff --git a/doc/src/sgml/ref/insert.sgml b/doc/src/sgml/ref/insert.sgml
index 06f4160..78107c6 100644
--- a/doc/src/sgml/ref/insert.sgml
+++ b/doc/src/sgml/ref/insert.sgml
@@ -23,6 +23,7 @@
 <synopsis>
 [ WITH [ RECURSIVE ] <replaceable class="parameter">with_query</replaceable> [, ...] ]
 INSERT INTO <replaceable class="PARAMETER">table_name</replaceable> [ AS <replaceable class="parameter">alias</replaceable> ] [ ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ]
+    [ OVERRIDING { SYSTEM | USER} VALUE ]
     { DEFAULT VALUES | VALUES ( { <replaceable class="PARAMETER">expression</replaceable> | DEFAULT } [, ...] ) [, ...] | <replaceable class="PARAMETER">query</replaceable> }
     [ ON CONFLICT [ <replaceable class="parameter">conflict_target</replaceable> ] <replaceable class="parameter">conflict_action</replaceable> ]
     [ RETURNING * | <replaceable class="parameter">output_expression</replaceable> [ [ AS ] <replaceable class="parameter">output_name</replaceable> ] [, ...] ]
@@ -202,6 +203,37 @@ <title id="sql-inserting-params-title">Inserting</title>
      </varlistentry>
 
      <varlistentry>
+      <term><literal>OVERRIDING SYSTEM VALUE</literal></term>
+      <listitem>
+       <para>
+        Without this clause, it is an error to specify an explicit value
+        (other than <literal>DEFAULT</literal>) for an identity column defined
+        as <literal>GENERATED ALWAYS</literal>.  This clause overrides that
+        restriction.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><literal>OVERRIDING USER VALUE</literal></term>
+      <listitem>
+       <para>
+        If this clause is specified, then any values supplied for identity
+        columns defined as <literal>GENERATED BY DEFAULT</literal> are ignored
+        and the default sequence-generated values are applied.
+       </para>
+
+       <para>
+        This clause is useful for example when copying values between tables.
+        Writing <literal>INSERT INTO tbl2 OVERRIDING USER VALUE SELECT * FROM
+        tbl1</literal> will copy from <literal>tbl1</literal> all columns that
+        are not identity columns in <literal>tbl2</literal> but continue the
+        sequence counters for any identity columns.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>DEFAULT VALUES</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index b56d0e3..8a8244e 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -149,6 +149,7 @@ CreateTupleDescCopy(TupleDesc tupdesc)
 		memcpy(desc->attrs[i], tupdesc->attrs[i], ATTRIBUTE_FIXED_PART_SIZE);
 		desc->attrs[i]->attnotnull = false;
 		desc->attrs[i]->atthasdef = false;
+		desc->attrs[i]->attidentity = ' ';
 	}
 
 	desc->tdtypeid = tupdesc->tdtypeid;
@@ -256,6 +257,7 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	/* since we're not copying constraints or defaults, clear these */
 	dst->attrs[dstAttno - 1]->attnotnull = false;
 	dst->attrs[dstAttno - 1]->atthasdef = false;
+	dst->attrs[dstAttno - 1]->attidentity = ' ';
 }
 
 /*
@@ -400,6 +402,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->atthasdef != attr2->atthasdef)
 			return false;
+		if (attr1->attidentity != attr2->attidentity)
+			return false;
 		if (attr1->attisdropped != attr2->attisdropped)
 			return false;
 		if (attr1->attislocal != attr2->attislocal)
@@ -533,6 +537,7 @@ TupleDescInitEntry(TupleDesc desc,
 
 	att->attnotnull = false;
 	att->atthasdef = false;
+	att->attidentity = ' ';
 	att->attisdropped = false;
 	att->attislocal = true;
 	att->attinhcount = 0;
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index 26d1652..f0d79c3 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -409,6 +409,7 @@ sub emit_pgattr_row
 		attcacheoff   => '-1',
 		atttypmod     => '-1',
 		atthasdef     => 'f',
+		attidentity   => "' '",
 		attisdropped  => 'f',
 		attislocal    => 't',
 		attinhcount   => '0',
@@ -425,6 +426,7 @@ sub bki_insert
 	my @attnames   = @_;
 	my $oid        = $row->{oid} ? "OID = $row->{oid} " : '';
 	my $bki_values = join ' ', map $row->{$_}, @attnames;
+	$bki_values =~ s/'/"/g;
 	printf BKI "insert %s( %s)\n", $oid, $bki_values;
 }
 
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index e997b57..9654164 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -138,37 +138,37 @@ static List *insert_ordered_unique_oid(List *list, Oid datum);
 static FormData_pg_attribute a1 = {
 	0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
 	SelfItemPointerAttributeNumber, 0, -1, -1,
-	false, 'p', 's', true, false, false, true, 0
+	false, 'p', 's', true, false, ' ', false, true, 0
 };
 
 static FormData_pg_attribute a2 = {
 	0, {"oid"}, OIDOID, 0, sizeof(Oid),
 	ObjectIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 static FormData_pg_attribute a3 = {
 	0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
 	MinTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 static FormData_pg_attribute a4 = {
 	0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
 	MinCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 static FormData_pg_attribute a5 = {
 	0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
 	MaxTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 static FormData_pg_attribute a6 = {
 	0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
 	MaxCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 /*
@@ -180,7 +180,7 @@ static FormData_pg_attribute a6 = {
 static FormData_pg_attribute a7 = {
 	0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
 	TableOidAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, true, 0
+	true, 'p', 'i', true, false, ' ', false, true, 0
 };
 
 static const Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7};
@@ -624,6 +624,7 @@ InsertPgAttributeTuple(Relation pg_attribute_rel,
 	values[Anum_pg_attribute_attalign - 1] = CharGetDatum(new_attribute->attalign);
 	values[Anum_pg_attribute_attnotnull - 1] = BoolGetDatum(new_attribute->attnotnull);
 	values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(new_attribute->atthasdef);
+	values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(new_attribute->attidentity);
 	values[Anum_pg_attribute_attisdropped - 1] = BoolGetDatum(new_attribute->attisdropped);
 	values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(new_attribute->attislocal);
 	values[Anum_pg_attribute_attinhcount - 1] = Int32GetDatum(new_attribute->attinhcount);
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index b0b43cf..b2ec40c 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -353,6 +353,7 @@ ConstructTupleDescriptor(Relation heapRelation,
 			to->attcacheoff = -1;
 			to->attnotnull = false;
 			to->atthasdef = false;
+			to->attidentity = ' ';
 			to->attislocal = true;
 			to->attinhcount = 0;
 			to->attcollation = collationObjectId[i];
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql
index 00550eb..88a4577 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -727,8 +727,8 @@ CREATE VIEW columns AS
            CAST(a.attnum AS sql_identifier) AS dtd_identifier,
            CAST('NO' AS yes_or_no) AS is_self_referencing,
 
-           CAST('NO' AS yes_or_no) AS is_identity,
-           CAST(null AS character_data) AS identity_generation,
+           CAST(CASE WHEN a.attidentity IN ('a', 'd') THEN 'YES' ELSE 'NO' END AS yes_or_no) AS is_identity,
+           CAST(CASE a.attidentity WHEN 'a' THEN 'ALWAYS' WHEN 'd' THEN 'BY DEFAULT' END AS character_data) AS identity_generation,
            CAST(null AS character_data) AS identity_start,
            CAST(null AS character_data) AS identity_increment,
            CAST(null AS character_data) AS identity_maximum,
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 7a0713e..0823b88 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -19,6 +19,7 @@
 #include "access/htup_details.h"
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
+#include "catalog/pg_attrdef.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_depend.h"
 #include "catalog/pg_extension.h"
@@ -554,17 +555,20 @@ markSequenceUnowned(Oid seqId)
 {
 	deleteDependencyRecordsForClass(RelationRelationId, seqId,
 									RelationRelationId, DEPENDENCY_AUTO);
+	deleteDependencyRecordsForClass(RelationRelationId, seqId,
+									AttrDefaultRelationId, DEPENDENCY_INTERNAL);
 }
 
 /*
- * Collect a list of OIDs of all sequences owned by the specified relation.
+ * Collect a list of OIDs of all sequences owned by the specified relation,
+ * and column if specified.
  */
 List *
-getOwnedSequences(Oid relid)
+getOwnedSequences(Oid relid, AttrNumber attnum)
 {
 	List	   *result = NIL;
 	Relation	depRel;
-	ScanKeyData key[2];
+	ScanKeyData key[3];
 	SysScanDesc scan;
 	HeapTuple	tup;
 
@@ -578,9 +582,14 @@ getOwnedSequences(Oid relid)
 				Anum_pg_depend_refobjid,
 				BTEqualStrategyNumber, F_OIDEQ,
 				ObjectIdGetDatum(relid));
+	if (attnum)
+		ScanKeyInit(&key[2],
+					Anum_pg_depend_refobjsubid,
+					BTEqualStrategyNumber, F_INT4EQ,
+					Int32GetDatum(attnum));
 
 	scan = systable_beginscan(depRel, DependReferenceIndexId, true,
-							  NULL, 2, key);
+							  NULL, attnum ? 3 : 2, key);
 
 	while (HeapTupleIsValid(tup = systable_getnext(scan)))
 	{
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index c98f981..810ae3b 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -22,8 +22,10 @@
 #include "access/xloginsert.h"
 #include "access/xlogutils.h"
 #include "catalog/dependency.h"
+#include "catalog/indexing.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/pg_attrdef.h"
 #include "catalog/pg_type.h"
 #include "commands/defrem.h"
 #include "commands/sequence.h"
@@ -36,6 +38,7 @@
 #include "storage/smgr.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/fmgroids.h"
 #include "utils/lsyscache.h"
 #include "utils/resowner.h"
 #include "utils/syscache.h"
@@ -95,9 +98,9 @@ static void init_sequence(Oid relid, SeqTable *p_elm, Relation *p_rel);
 static Form_pg_sequence read_seq_tuple(SeqTable elm, Relation rel,
 			   Buffer *buf, HeapTuple seqtuple);
 static void init_params(List *options, bool isInit,
-			Form_pg_sequence new, List **owned_by);
+						Form_pg_sequence new, List **owned_by, DependencyType *deptype);
 static void do_setval(Oid relid, int64 next, bool iscalled);
-static void process_owned_by(Relation seqrel, List *owned_by);
+static void process_owned_by(Relation seqrel, List *owned_by, DependencyType deptype);
 
 
 /*
@@ -109,6 +112,7 @@ DefineSequence(CreateSeqStmt *seq)
 {
 	FormData_pg_sequence new;
 	List	   *owned_by;
+	DependencyType deptype;
 	CreateStmt *stmt = makeNode(CreateStmt);
 	Oid			seqoid;
 	ObjectAddress address;
@@ -145,7 +149,7 @@ DefineSequence(CreateSeqStmt *seq)
 	}
 
 	/* Check and set all option values */
-	init_params(seq->options, true, &new, &owned_by);
+	init_params(seq->options, true, &new, &owned_by, &deptype);
 
 	/*
 	 * Create relation (and fill value[] and null[] for the tuple)
@@ -247,7 +251,7 @@ DefineSequence(CreateSeqStmt *seq)
 
 	/* process OWNED BY if given */
 	if (owned_by)
-		process_owned_by(rel, owned_by);
+		process_owned_by(rel, owned_by, deptype);
 
 	heap_close(rel, NoLock);
 
@@ -414,6 +418,7 @@ AlterSequence(AlterSeqStmt *stmt)
 	Form_pg_sequence seq;
 	FormData_pg_sequence new;
 	List	   *owned_by;
+	DependencyType deptype;
 	ObjectAddress address;
 
 	/* Open and lock sequence. */
@@ -440,7 +445,7 @@ AlterSequence(AlterSeqStmt *stmt)
 	memcpy(&new, seq, sizeof(FormData_pg_sequence));
 
 	/* Check and set new values */
-	init_params(stmt->options, false, &new, &owned_by);
+	init_params(stmt->options, false, &new, &owned_by, &deptype);
 
 	/* Clear local cache so that we don't think we have cached numbers */
 	/* Note that we do not change the currval() state */
@@ -483,7 +488,7 @@ AlterSequence(AlterSeqStmt *stmt)
 
 	/* process OWNED BY if given */
 	if (owned_by)
-		process_owned_by(seqrel, owned_by);
+		process_owned_by(seqrel, owned_by, deptype);
 
 	InvokeObjectPostAlterHook(RelationRelationId, relid, 0);
 
@@ -1164,7 +1169,7 @@ read_seq_tuple(SeqTable elm, Relation rel, Buffer *buf, HeapTuple seqtuple)
  */
 static void
 init_params(List *options, bool isInit,
-			Form_pg_sequence new, List **owned_by)
+			Form_pg_sequence new, List **owned_by, DependencyType *deptype)
 {
 	DefElem    *start_value = NULL;
 	DefElem    *restart_value = NULL;
@@ -1173,9 +1178,11 @@ init_params(List *options, bool isInit,
 	DefElem    *min_value = NULL;
 	DefElem    *cache_value = NULL;
 	DefElem    *is_cycled = NULL;
+	DefElem	   *deptype_el = NULL;
 	ListCell   *option;
 
 	*owned_by = NIL;
+	*deptype = DEPENDENCY_AUTO;
 
 	foreach(option, options)
 	{
@@ -1245,6 +1252,15 @@ init_params(List *options, bool isInit,
 						 errmsg("conflicting or redundant options")));
 			*owned_by = defGetQualifiedName(defel);
 		}
+		else if (strcmp(defel->defname, "deptype") == 0)
+		{
+			if (deptype_el)
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+						 errmsg("conflicting or redundant options")));
+			deptype_el = defel;
+			*deptype = intVal(deptype_el->arg);
+		}
 		else
 			elog(ERROR, "option \"%s\" not recognized",
 				 defel->defname);
@@ -1423,6 +1439,38 @@ init_params(List *options, bool isInit,
 		new->cache_value = 1;
 }
 
+static Oid
+get_attrdef_oid(Oid relid, AttrNumber attnum)
+{
+	Relation    attrdef_rel;
+	ScanKeyData scankeys[2];
+	SysScanDesc scan;
+	HeapTuple   tuple;
+	Oid			result = InvalidOid;
+
+	attrdef_rel = heap_open(AttrDefaultRelationId, RowExclusiveLock);
+
+	ScanKeyInit(&scankeys[0],
+				Anum_pg_attrdef_adrelid,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(relid));
+	ScanKeyInit(&scankeys[1],
+				Anum_pg_attrdef_adnum,
+				BTEqualStrategyNumber, F_INT2EQ,
+				Int16GetDatum(attnum));
+
+	scan = systable_beginscan(attrdef_rel, AttrDefaultIndexId, true,
+							  NULL, 2, scankeys);
+
+	if (HeapTupleIsValid(tuple = systable_getnext(scan)))
+		result = HeapTupleGetOid(tuple);
+
+	systable_endscan(scan);
+	heap_close(attrdef_rel, RowExclusiveLock);
+
+	return result;
+}
+
 /*
  * Process an OWNED BY option for CREATE/ALTER SEQUENCE
  *
@@ -1432,7 +1480,7 @@ init_params(List *options, bool isInit,
  * as the sequence.
  */
 static void
-process_owned_by(Relation seqrel, List *owned_by)
+process_owned_by(Relation seqrel, List *owned_by, DependencyType deptype)
 {
 	int			nnames;
 	Relation	tablerel;
@@ -1510,6 +1558,20 @@ process_owned_by(Relation seqrel, List *owned_by)
 		depobject.objectId = RelationGetRelid(seqrel);
 		depobject.objectSubId = 0;
 		recordDependencyOn(&depobject, &refobject, DEPENDENCY_AUTO);
+
+		/*
+		 * For identity columns, also record an internal dependency of the
+		 * sequence on the default (you drop the default, the sequence is
+		 * removed).  We still do the auto dependency on the column, because
+		 * that is what TRUNCATE RESTART IDENTITY looks for.
+		 */
+		if (deptype == DEPENDENCY_INTERNAL)
+		{
+			refobject.classId = AttrDefaultRelationId;
+			refobject.objectId = get_attrdef_oid(RelationGetRelid(tablerel), attnum);
+			refobject.objectSubId = 0;
+			recordDependencyOn(&depobject, &refobject, DEPENDENCY_INTERNAL);
+		}
 	}
 
 	/* Done, but hold lock until commit */
@@ -1519,6 +1581,35 @@ process_owned_by(Relation seqrel, List *owned_by)
 
 
 /*
+ * Return sequence parameters in a list of the form created by the parser.
+ */
+List *
+sequence_options(Oid relid)
+{
+	SeqTable	elm;
+	Relation	seqrel;
+	Buffer		buf;
+	HeapTupleData seqtuple;
+	Form_pg_sequence seq;
+	List	   *options = NIL;
+
+	init_sequence(relid, &elm, &seqrel);
+	seq = read_seq_tuple(elm, seqrel, &buf, &seqtuple);
+
+	options = lappend(options, makeDefElem("cache", (Node *) makeInteger(seq->cache_value)));
+	options = lappend(options, makeDefElem("cycle", (Node *) makeInteger(seq->is_cycled)));
+	options = lappend(options, makeDefElem("increment", (Node *) makeInteger(seq->increment_by)));
+	options = lappend(options, makeDefElem("maxvalue", (Node *) makeInteger(seq->max_value)));
+	options = lappend(options, makeDefElem("minvalue", (Node *) makeInteger(seq->min_value)));
+	options = lappend(options, makeDefElem("start", (Node *) makeInteger(seq->start_value)));
+
+	UnlockReleaseBuffer(buf);
+	relation_close(seqrel, NoLock);
+
+	return options;
+}
+
+/*
  * Return sequence parameters, for use by information schema
  */
 Datum
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 86e9814..0c8e78a 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -344,6 +344,9 @@ static ObjectAddress ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 const char *colName, LOCKMODE lockmode);
 static ObjectAddress ATExecColumnDefault(Relation rel, const char *colName,
 					Node *newDefault, LOCKMODE lockmode);
+static ObjectAddress ATExecAddIdentity(Relation rel, const char *colName,
+					Node *def, LOCKMODE lockmode);
+static ObjectAddress ATExecDropIdentity(Relation rel, const char *colName, LOCKMODE lockmode);
 static void ATPrepSetStatistics(Relation rel, const char *colName,
 					Node *newValue, LOCKMODE lockmode);
 static ObjectAddress ATExecSetStatistics(Relation rel, const char *colName,
@@ -650,6 +653,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 			cookedDefaults = lappend(cookedDefaults, cooked);
 			descriptor->attrs[attnum - 1]->atthasdef = true;
 		}
+
+		if (colDef->identity)
+			descriptor->attrs[attnum - 1]->attidentity = colDef->identity;
 	}
 
 	/*
@@ -1113,7 +1119,7 @@ ExecuteTruncate(TruncateStmt *stmt)
 		foreach(cell, rels)
 		{
 			Relation	rel = (Relation) lfirst(cell);
-			List	   *seqlist = getOwnedSequences(RelationGetRelid(rel));
+			List	   *seqlist = getOwnedSequences(RelationGetRelid(rel), 0);
 			ListCell   *seqcell;
 
 			foreach(seqcell, seqlist)
@@ -2941,6 +2947,8 @@ AlterTableGetLockLevel(List *cmds)
 			case AT_DisableRowSecurity:
 			case AT_ForceRowSecurity:
 			case AT_NoForceRowSecurity:
+			case AT_AddIdentity:
+			case AT_DropIdentity:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -3154,6 +3162,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_ADD_COL;
 			break;
 		case AT_ColumnDefault:	/* ALTER COLUMN DEFAULT */
+		case AT_AddIdentity:
+		case AT_DropIdentity:
 
 			/*
 			 * We allow defaults on views so that INSERT into a view can have
@@ -3476,6 +3486,12 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_ColumnDefault:	/* ALTER COLUMN DEFAULT */
 			address = ATExecColumnDefault(rel, cmd->name, cmd->def, lockmode);
 			break;
+		case AT_AddIdentity:
+			address = ATExecAddIdentity(rel, cmd->name, cmd->def, lockmode);
+			break;
+		case AT_DropIdentity:
+			address = ATExecDropIdentity(rel, cmd->name, lockmode);
+			break;
 		case AT_DropNotNull:	/* ALTER COLUMN DROP NOT NULL */
 			address = ATExecDropNotNull(rel, cmd->name, lockmode);
 			break;
@@ -5405,6 +5421,125 @@ ATExecColumnDefault(Relation rel, const char *colName,
 }
 
 /*
+ * ALTER TABLE ALTER COLUMN ADD IDENTITY
+ *
+ * Return the address of the affected column.
+ */
+static ObjectAddress
+ATExecAddIdentity(Relation rel, const char *colName,
+				  Node *def, LOCKMODE lockmode)
+{
+	Relation	attrelation;
+	HeapTuple	tuple;
+	Form_pg_attribute attTup;
+	AttrNumber	attnum;
+	RawColumnDefault *rawEnt;
+	ObjectAddress address;
+	ColumnDef  *cdef = (ColumnDef *) def;
+
+	Assert(IsA(def, ColumnDef));
+
+	attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = attTup->attnum;
+
+	/* Can't alter a system attribute */
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"",
+						colName)));
+
+	if (attTup->attidentity != ' ')
+		ereport(ERROR,
+				(errmsg("column \"%s\" of relation \"%s\" is already an identity column",
+						colName, RelationGetRelationName(rel))));
+
+	attTup->attidentity = cdef->identity;
+	simple_heap_update(attrelation, &tuple->t_self, tuple);
+	CatalogUpdateIndexes(attrelation, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  attTup->attnum);
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), attnum);
+	heap_freetuple(tuple);
+
+	CommandCounterIncrement();
+
+	rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
+	rawEnt->attnum = attnum;
+	rawEnt->raw_default = cdef->raw_default;
+
+	AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
+							  false, true, false);
+
+	heap_close(attrelation, RowExclusiveLock);
+
+	return address;
+}
+
+static ObjectAddress
+ATExecDropIdentity(Relation rel, const char *colName, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	Form_pg_attribute attTup;
+	AttrNumber	attnum;
+	Relation	attrelation;
+	ObjectAddress address;
+
+	attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
+	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+
+	attTup = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = attTup->attnum;
+
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"",
+						colName)));
+
+	if (attTup->attidentity == ' ')
+		ereport(ERROR,
+				(errmsg("column \"%s\" of relation \"%s\" is not an identity column",
+						colName, RelationGetRelationName(rel))));
+
+	attTup->attidentity = ' ';
+	simple_heap_update(attrelation, &tuple->t_self, tuple);
+	CatalogUpdateIndexes(attrelation, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  attTup->attnum);
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), attnum);
+	heap_freetuple(tuple);
+
+	CommandCounterIncrement();
+
+	RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false,
+					  true);
+
+	heap_close(attrelation, RowExclusiveLock);
+
+	return address;
+}
+
+/*
  * ALTER TABLE ALTER COLUMN SET STATISTICS
  */
 static void
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 1877fb4..bc0a1a2 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2624,6 +2624,7 @@ _copyColumnDef(const ColumnDef *from)
 	COPY_SCALAR_FIELD(storage);
 	COPY_NODE_FIELD(raw_default);
 	COPY_NODE_FIELD(cooked_default);
+	COPY_SCALAR_FIELD(identity);
 	COPY_NODE_FIELD(collClause);
 	COPY_SCALAR_FIELD(collOid);
 	COPY_NODE_FIELD(constraints);
@@ -2646,6 +2647,7 @@ _copyConstraint(const Constraint *from)
 	COPY_SCALAR_FIELD(is_no_inherit);
 	COPY_NODE_FIELD(raw_expr);
 	COPY_STRING_FIELD(cooked_expr);
+	COPY_SCALAR_FIELD(generated_when);
 	COPY_NODE_FIELD(keys);
 	COPY_NODE_FIELD(exclusions);
 	COPY_NODE_FIELD(options);
@@ -2740,6 +2742,7 @@ _copyQuery(const Query *from)
 	COPY_NODE_FIELD(rtable);
 	COPY_NODE_FIELD(jointree);
 	COPY_NODE_FIELD(targetList);
+	COPY_SCALAR_FIELD(override);
 	COPY_NODE_FIELD(onConflict);
 	COPY_NODE_FIELD(returningList);
 	COPY_NODE_FIELD(groupClause);
@@ -2769,6 +2772,7 @@ _copyInsertStmt(const InsertStmt *from)
 	COPY_NODE_FIELD(onConflictClause);
 	COPY_NODE_FIELD(returningList);
 	COPY_NODE_FIELD(withClause);
+	COPY_SCALAR_FIELD(override);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 448e1a9..8719bdd 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -931,6 +931,7 @@ _equalQuery(const Query *a, const Query *b)
 	COMPARE_NODE_FIELD(rtable);
 	COMPARE_NODE_FIELD(jointree);
 	COMPARE_NODE_FIELD(targetList);
+	COMPARE_SCALAR_FIELD(override);
 	COMPARE_NODE_FIELD(onConflict);
 	COMPARE_NODE_FIELD(returningList);
 	COMPARE_NODE_FIELD(groupClause);
@@ -958,6 +959,7 @@ _equalInsertStmt(const InsertStmt *a, const InsertStmt *b)
 	COMPARE_NODE_FIELD(onConflictClause);
 	COMPARE_NODE_FIELD(returningList);
 	COMPARE_NODE_FIELD(withClause);
+	COMPARE_SCALAR_FIELD(override);
 
 	return true;
 }
@@ -2376,6 +2378,7 @@ _equalColumnDef(const ColumnDef *a, const ColumnDef *b)
 	COMPARE_SCALAR_FIELD(storage);
 	COMPARE_NODE_FIELD(raw_default);
 	COMPARE_NODE_FIELD(cooked_default);
+	COMPARE_SCALAR_FIELD(identity);
 	COMPARE_NODE_FIELD(collClause);
 	COMPARE_SCALAR_FIELD(collOid);
 	COMPARE_NODE_FIELD(constraints);
@@ -2396,6 +2399,7 @@ _equalConstraint(const Constraint *a, const Constraint *b)
 	COMPARE_SCALAR_FIELD(is_no_inherit);
 	COMPARE_NODE_FIELD(raw_expr);
 	COMPARE_STRING_FIELD(cooked_expr);
+	COMPARE_SCALAR_FIELD(generated_when);
 	COMPARE_NODE_FIELD(keys);
 	COMPARE_NODE_FIELD(exclusions);
 	COMPARE_NODE_FIELD(options);
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index d72a85e..e32b258 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -497,6 +497,7 @@ makeColumnDef(const char *colname, Oid typeOid, int32 typmod, Oid collOid)
 	n->storage = 0;
 	n->raw_default = NULL;
 	n->cooked_default = NULL;
+	n->identity = 0;
 	n->collClause = NULL;
 	n->collOid = collOid;
 	n->constraints = NIL;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 29b7712..a82a2ff 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2588,6 +2588,7 @@ _outColumnDef(StringInfo str, const ColumnDef *node)
 	WRITE_CHAR_FIELD(storage);
 	WRITE_NODE_FIELD(raw_default);
 	WRITE_NODE_FIELD(cooked_default);
+	WRITE_CHAR_FIELD(identity);
 	WRITE_NODE_FIELD(collClause);
 	WRITE_OID_FIELD(collOid);
 	WRITE_NODE_FIELD(constraints);
@@ -2692,6 +2693,7 @@ _outQuery(StringInfo str, const Query *node)
 	WRITE_NODE_FIELD(rtable);
 	WRITE_NODE_FIELD(jointree);
 	WRITE_NODE_FIELD(targetList);
+	WRITE_ENUM_FIELD(override, OverridingKind);
 	WRITE_NODE_FIELD(onConflict);
 	WRITE_NODE_FIELD(returningList);
 	WRITE_NODE_FIELD(groupClause);
@@ -3186,6 +3188,13 @@ _outConstraint(StringInfo str, const Constraint *node)
 			WRITE_STRING_FIELD(cooked_expr);
 			break;
 
+		case CONSTR_IDENTITY:
+			appendStringInfoString(str, "IDENTITY");
+			WRITE_NODE_FIELD(raw_expr);
+			WRITE_STRING_FIELD(cooked_expr);
+			WRITE_CHAR_FIELD(generated_when);
+			break;
+
 		case CONSTR_CHECK:
 			appendStringInfoString(str, "CHECK");
 			WRITE_BOOL_FIELD(is_no_inherit);
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index 6f9a81e..c12d254 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -248,6 +248,7 @@ _readQuery(void)
 	READ_NODE_FIELD(rtable);
 	READ_NODE_FIELD(jointree);
 	READ_NODE_FIELD(targetList);
+	READ_ENUM_FIELD(override, OverridingKind);
 	READ_NODE_FIELD(onConflict);
 	READ_NODE_FIELD(returningList);
 	READ_NODE_FIELD(groupClause);
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index eac86cc..26f9722 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -463,6 +463,8 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 		qry->hasModifyingCTE = pstate->p_hasModifyingCTE;
 	}
 
+	qry->override = stmt->override;
+
 	isOnConflictUpdate = (stmt->onConflictClause &&
 						stmt->onConflictClause->action == ONCONFLICT_UPDATE);
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index cb5cfc4..5fcdf78 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -424,7 +424,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 				select_offset_value2 opt_select_fetch_first_value
 %type <ival>	row_or_rows first_or_next
 
-%type <list>	OptSeqOptList SeqOptList
+%type <list>	OptSeqOptList SeqOptList OptParenthesizedSeqOptList
 %type <defelt>	SeqOptElem
 
 %type <istmt>	insert_rest
@@ -541,6 +541,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 				opt_frame_clause frame_extent frame_bound
 %type <str>		opt_existing_window_name
 %type <boolean> opt_if_not_exists
+%type <ival>	generated_when override_kind
 
 /*
  * Non-keyword token types.  These are hard-wired into the "flex" lexer.
@@ -591,7 +592,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	FALSE_P FAMILY FETCH FILTER FIRST_P FLOAT_P FOLLOWING FOR
 	FORCE FOREIGN FORWARD FREEZE FROM FULL FUNCTION FUNCTIONS
 
-	GLOBAL GRANT GRANTED GREATEST GROUP_P GROUPING
+	GENERATED GLOBAL GRANT GRANTED GREATEST GROUP_P GROUPING
 
 	HANDLER HAVING HEADER_P HOLD HOUR_P
 
@@ -615,7 +616,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	NULLS_P NUMERIC
 
 	OBJECT_P OF OFF OFFSET OIDS ON ONLY OPERATOR OPTION OPTIONS OR
-	ORDER ORDINALITY OUT_P OUTER_P OVER OVERLAPS OVERLAY OWNED OWNER
+	ORDER ORDINALITY OUT_P OUTER_P OVER OVERLAPS OVERLAY OVERRIDING OWNED OWNER
 
 	PARALLEL PARSER PARTIAL PARTITION PASSING PASSWORD PLACING PLANS POLICY
 	POSITION PRECEDING PRECISION PRESERVE PREPARE PREPARED PRIMARY
@@ -2026,6 +2027,31 @@ alter_table_cmd:
 					n->def = (Node *) makeString($6);
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> ADD GENERATED ... AS IDENTITY ... */
+			| ALTER opt_column ColId ADD_P GENERATED generated_when AS IDENTITY_P OptParenthesizedSeqOptList
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					Constraint *c = makeNode(Constraint);
+
+					c->contype = CONSTR_IDENTITY;
+					c->generated_when = $6;
+					c->options = $9;
+					c->location = @5;
+
+					n->subtype = AT_AddIdentity;
+					n->name = $3;
+					n->def = (Node *) c;
+
+					$$ = (Node *)n;
+				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> DROP IDENTITY */
+			| ALTER opt_column ColId DROP IDENTITY_P
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_DropIdentity;
+					n->name = $3;
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
@@ -3097,6 +3123,15 @@ ColConstraintElem:
 					n->cooked_expr = NULL;
 					$$ = (Node *)n;
 				}
+			| GENERATED generated_when AS IDENTITY_P OptParenthesizedSeqOptList
+				{
+					Constraint *n = makeNode(Constraint);
+					n->contype = CONSTR_IDENTITY;
+					n->generated_when = $2;
+					n->options = $5;
+					n->location = @1;
+					$$ = (Node *)n;
+				}
 			| REFERENCES qualified_name opt_column_list key_match key_actions
 				{
 					Constraint *n = makeNode(Constraint);
@@ -3114,6 +3149,11 @@ ColConstraintElem:
 				}
 		;
 
+generated_when:
+			ALWAYS			{ $$ = CONSTR_GENERATED_ALWAYS; }
+			| BY DEFAULT	{ $$ = CONSTR_GENERATED_DEFAULT; }
+		;
+
 /*
  * ConstraintAttr represents constraint attributes, which we parse as if
  * they were independent constraint clauses, in order to avoid shift/reduce
@@ -3180,6 +3220,7 @@ TableLikeOptionList:
 TableLikeOption:
 				DEFAULTS			{ $$ = CREATE_TABLE_LIKE_DEFAULTS; }
 				| CONSTRAINTS		{ $$ = CREATE_TABLE_LIKE_CONSTRAINTS; }
+				| IDENTITY_P		{ $$ = CREATE_TABLE_LIKE_IDENTITY; }
 				| INDEXES			{ $$ = CREATE_TABLE_LIKE_INDEXES; }
 				| STORAGE			{ $$ = CREATE_TABLE_LIKE_STORAGE; }
 				| COMMENTS			{ $$ = CREATE_TABLE_LIKE_COMMENTS; }
@@ -3630,6 +3671,10 @@ OptSeqOptList: SeqOptList							{ $$ = $1; }
 			| /*EMPTY*/								{ $$ = NIL; }
 		;
 
+OptParenthesizedSeqOptList: '(' SeqOptList ')'		{ $$ = $2; }
+			| /*EMPTY*/								{ $$ = NIL; }
+		;
+
 SeqOptList: SeqOptElem								{ $$ = list_make1($1); }
 			| SeqOptList SeqOptElem					{ $$ = lappend($1, $2); }
 		;
@@ -9655,12 +9700,26 @@ insert_rest:
 					$$->cols = NIL;
 					$$->selectStmt = $1;
 				}
+			| OVERRIDING override_kind VALUE_P SelectStmt
+				{
+					$$ = makeNode(InsertStmt);
+					$$->cols = NIL;
+					$$->override = $2;
+					$$->selectStmt = $4;
+				}
 			| '(' insert_column_list ')' SelectStmt
 				{
 					$$ = makeNode(InsertStmt);
 					$$->cols = $2;
 					$$->selectStmt = $4;
 				}
+			| '(' insert_column_list ')' OVERRIDING override_kind VALUE_P SelectStmt
+				{
+					$$ = makeNode(InsertStmt);
+					$$->cols = $2;
+					$$->override = $5;
+					$$->selectStmt = $7;
+				}
 			| DEFAULT VALUES
 				{
 					$$ = makeNode(InsertStmt);
@@ -9669,6 +9728,11 @@ insert_rest:
 				}
 		;
 
+override_kind:
+			USER		{ $$ = OVERRIDING_USER_VALUE; }
+			| SYSTEM_P	{ $$ = OVERRIDING_SYSTEM_VALUE; }
+		;
+
 insert_column_list:
 			insert_column_item
 					{ $$ = list_make1($1); }
@@ -13802,6 +13866,7 @@ unreserved_keyword:
 			| OPTIONS
 			| ORDINALITY
 			| OVER
+			| OVERRIDING
 			| OWNED
 			| OWNER
 			| PARALLEL
@@ -14060,6 +14125,7 @@ reserved_keyword:
 			| FOR
 			| FOREIGN
 			| FROM
+			| GENERATED
 			| GRANT
 			| GROUP_P
 			| HAVING
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index e98fad0..34de410 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -42,6 +42,7 @@
 #include "catalog/pg_type.h"
 #include "commands/comment.h"
 #include "commands/defrem.h"
+#include "commands/sequence.h"
 #include "commands/tablecmds.h"
 #include "commands/tablespace.h"
 #include "miscadmin.h"
@@ -342,6 +343,120 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	return result;
 }
 
+static void
+generateSerialExtraStmts(CreateStmtContext *cxt, ColumnDef *column, List *seqoptions, DependencyType deptype,
+						 char **snamespace_p, char **sname_p)
+{
+	Oid			snamespaceid;
+	char	   *snamespace;
+	char	   *sname;
+	CreateSeqStmt *seqstmt;
+	AlterSeqStmt *altseqstmt;
+	List	   *attnamelist;
+
+	/*
+	 * Determine namespace and name to use for the sequence.
+	 *
+	 * Although we use ChooseRelationName, it's not guaranteed that the
+	 * selected sequence name won't conflict; given sufficiently long
+	 * field names, two different serial columns in the same table could
+	 * be assigned the same sequence name, and we'd not notice since we
+	 * aren't creating the sequence quite yet.  In practice this seems
+	 * quite unlikely to be a problem, especially since few people would
+	 * need two serial columns in one table.
+	 */
+	if (cxt->rel)
+		snamespaceid = RelationGetNamespace(cxt->rel);
+	else
+	{
+		snamespaceid = RangeVarGetCreationNamespace(cxt->relation);
+		RangeVarAdjustRelationPersistence(cxt->relation, snamespaceid);
+	}
+	snamespace = get_namespace_name(snamespaceid);
+	sname = ChooseRelationName(cxt->relation->relname,
+							   column->colname,
+							   "seq",
+							   snamespaceid);
+
+	ereport(DEBUG1,
+			(errmsg("%s will create implicit sequence \"%s\" for serial column \"%s.%s\"",
+					cxt->stmtType, sname,
+					cxt->relation->relname, column->colname)));
+
+	/*
+	 * Build a CREATE SEQUENCE command to create the sequence object, and
+	 * add it to the list of things to be done before this CREATE/ALTER
+	 * TABLE.
+	 */
+	seqstmt = makeNode(CreateSeqStmt);
+	seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
+	seqstmt->options = seqoptions;
+
+	/*
+	 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
+	 * by the table's owner.  The current user might be someone else
+	 * (perhaps a superuser, or someone who's only a member of the owning
+	 * role), but the SEQUENCE OWNED BY mechanisms will bleat unless table
+	 * and sequence have exactly the same owning role.
+	 */
+	if (cxt->rel)
+		seqstmt->ownerId = cxt->rel->rd_rel->relowner;
+	else
+		seqstmt->ownerId = InvalidOid;
+
+	cxt->blist = lappend(cxt->blist, seqstmt);
+
+	/*
+	 * Build an ALTER SEQUENCE ... OWNED BY command to mark the sequence
+	 * as owned by this column, and add it to the list of things to be
+	 * done after this CREATE/ALTER TABLE.
+	 */
+	altseqstmt = makeNode(AlterSeqStmt);
+	altseqstmt->sequence = makeRangeVar(snamespace, sname, -1);
+	attnamelist = list_make3(makeString(snamespace),
+							 makeString(cxt->relation->relname),
+							 makeString(column->colname));
+	altseqstmt->options = list_make2(makeDefElem("owned_by",
+												 (Node *) attnamelist),
+									 makeDefElem("deptype",
+												 (Node *) makeInteger(deptype)));
+
+	cxt->alist = lappend(cxt->alist, altseqstmt);
+
+	*snamespace_p = snamespace;
+	*sname_p = sname;
+}
+
+/*
+ * Create an expression tree representing the function call
+ * nextval('sequencename').  We cannot reduce the raw tree to cooked
+ * form until after the sequence is created, but there's no need to do
+ * so.
+ */
+static FuncCall *
+generateNextvalExpr(char *snamespace, char *sname)
+{
+	char	   *qstring;
+	A_Const    *snamenode;
+	TypeCast   *castnode;
+	FuncCall   *funccallnode;
+
+	qstring = quote_qualified_identifier(snamespace, sname);
+	snamenode = makeNode(A_Const);
+	snamenode->val.type = T_String;
+	snamenode->val.val.str = qstring;
+	snamenode->location = -1;
+	castnode = makeNode(TypeCast);
+	castnode->typeName = SystemTypeName("regclass");
+	castnode->arg = (Node *) snamenode;
+	castnode->location = -1;
+	funccallnode = makeFuncCall(SystemFuncName("nextval"),
+								list_make1(castnode),
+								-1);
+
+	return funccallnode;
+}
+
 /*
  * transformColumnDefinition -
  *		transform a single ColumnDef within CREATE TABLE
@@ -353,7 +468,7 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 	bool		is_serial;
 	bool		saw_nullable;
 	bool		saw_default;
-	Constraint *constraint;
+	bool		saw_identity;
 	ListCell   *clist;
 
 	cxt->columns = lappend(cxt->columns, column);
@@ -408,110 +523,21 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 	/* Special actions for SERIAL pseudo-types */
 	if (is_serial)
 	{
-		Oid			snamespaceid;
 		char	   *snamespace;
 		char	   *sname;
-		char	   *qstring;
-		A_Const    *snamenode;
-		TypeCast   *castnode;
-		FuncCall   *funccallnode;
-		CreateSeqStmt *seqstmt;
-		AlterSeqStmt *altseqstmt;
-		List	   *attnamelist;
-
-		/*
-		 * Determine namespace and name to use for the sequence.
-		 *
-		 * Although we use ChooseRelationName, it's not guaranteed that the
-		 * selected sequence name won't conflict; given sufficiently long
-		 * field names, two different serial columns in the same table could
-		 * be assigned the same sequence name, and we'd not notice since we
-		 * aren't creating the sequence quite yet.  In practice this seems
-		 * quite unlikely to be a problem, especially since few people would
-		 * need two serial columns in one table.
-		 */
-		if (cxt->rel)
-			snamespaceid = RelationGetNamespace(cxt->rel);
-		else
-		{
-			snamespaceid = RangeVarGetCreationNamespace(cxt->relation);
-			RangeVarAdjustRelationPersistence(cxt->relation, snamespaceid);
-		}
-		snamespace = get_namespace_name(snamespaceid);
-		sname = ChooseRelationName(cxt->relation->relname,
-								   column->colname,
-								   "seq",
-								   snamespaceid);
-
-		ereport(DEBUG1,
-				(errmsg("%s will create implicit sequence \"%s\" for serial column \"%s.%s\"",
-						cxt->stmtType, sname,
-						cxt->relation->relname, column->colname)));
+		Constraint *constraint;
 
-		/*
-		 * Build a CREATE SEQUENCE command to create the sequence object, and
-		 * add it to the list of things to be done before this CREATE/ALTER
-		 * TABLE.
-		 */
-		seqstmt = makeNode(CreateSeqStmt);
-		seqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		seqstmt->options = NIL;
-
-		/*
-		 * If this is ALTER ADD COLUMN, make sure the sequence will be owned
-		 * by the table's owner.  The current user might be someone else
-		 * (perhaps a superuser, or someone who's only a member of the owning
-		 * role), but the SEQUENCE OWNED BY mechanisms will bleat unless table
-		 * and sequence have exactly the same owning role.
-		 */
-		if (cxt->rel)
-			seqstmt->ownerId = cxt->rel->rd_rel->relowner;
-		else
-			seqstmt->ownerId = InvalidOid;
-
-		cxt->blist = lappend(cxt->blist, seqstmt);
-
-		/*
-		 * Build an ALTER SEQUENCE ... OWNED BY command to mark the sequence
-		 * as owned by this column, and add it to the list of things to be
-		 * done after this CREATE/ALTER TABLE.
-		 */
-		altseqstmt = makeNode(AlterSeqStmt);
-		altseqstmt->sequence = makeRangeVar(snamespace, sname, -1);
-		attnamelist = list_make3(makeString(snamespace),
-								 makeString(cxt->relation->relname),
-								 makeString(column->colname));
-		altseqstmt->options = list_make1(makeDefElem("owned_by",
-													 (Node *) attnamelist));
-
-		cxt->alist = lappend(cxt->alist, altseqstmt);
+		generateSerialExtraStmts(cxt, column, NIL, DEPENDENCY_AUTO, &snamespace, &sname);
 
 		/*
 		 * Create appropriate constraints for SERIAL.  We do this in full,
 		 * rather than shortcutting, so that we will detect any conflicting
 		 * constraints the user wrote (like a different DEFAULT).
-		 *
-		 * Create an expression tree representing the function call
-		 * nextval('sequencename').  We cannot reduce the raw tree to cooked
-		 * form until after the sequence is created, but there's no need to do
-		 * so.
 		 */
-		qstring = quote_qualified_identifier(snamespace, sname);
-		snamenode = makeNode(A_Const);
-		snamenode->val.type = T_String;
-		snamenode->val.val.str = qstring;
-		snamenode->location = -1;
-		castnode = makeNode(TypeCast);
-		castnode->typeName = SystemTypeName("regclass");
-		castnode->arg = (Node *) snamenode;
-		castnode->location = -1;
-		funccallnode = makeFuncCall(SystemFuncName("nextval"),
-									list_make1(castnode),
-									-1);
 		constraint = makeNode(Constraint);
 		constraint->contype = CONSTR_DEFAULT;
 		constraint->location = -1;
-		constraint->raw_expr = (Node *) funccallnode;
+		constraint->raw_expr = (Node *) generateNextvalExpr(snamespace, sname);
 		constraint->cooked_expr = NULL;
 		column->constraints = lappend(column->constraints, constraint);
 
@@ -526,9 +552,12 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 
 	saw_nullable = false;
 	saw_default = false;
+	saw_identity = false;
 
 	foreach(clist, column->constraints)
 	{
+		Constraint *constraint;
+
 		constraint = lfirst(clist);
 		Assert(IsA(constraint, Constraint));
 
@@ -568,9 +597,43 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 												constraint->location)));
 				column->raw_default = constraint->raw_expr;
 				Assert(constraint->cooked_expr == NULL);
+				column->identity = ' ';
 				saw_default = true;
 				break;
 
+			case CONSTR_IDENTITY:
+			{
+				char	   *snamespace;
+				char	   *sname;
+				Type		ctype;
+				Oid			typeOid;
+
+				ctype = typenameType(cxt->pstate, column->typeName, NULL);
+				typeOid = HeapTupleGetOid(ctype);
+				ReleaseSysCache(ctype);
+
+				if (!(typeOid == INT2OID || typeOid == INT4OID || typeOid == INT8OID))
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("identity column type must be smallint, integer, or bigint")));
+
+				if (saw_identity)
+					ereport(ERROR,
+							(errcode(ERRCODE_SYNTAX_ERROR),
+							 errmsg("multiple identity specifications for column \"%s\" of table \"%s\"",
+									column->colname, cxt->relation->relname),
+							 parser_errposition(cxt->pstate,
+												constraint->location)));
+
+				generateSerialExtraStmts(cxt, column, constraint->options, DEPENDENCY_INTERNAL, &snamespace, &sname);
+				column->raw_default = (Node *) generateNextvalExpr(snamespace, sname);
+				Assert(constraint->cooked_expr == NULL);
+				column->identity = constraint->generated_when;
+				saw_identity = true;
+				column->is_not_null = TRUE;
+				break;
+			}
+
 			case CONSTR_CHECK:
 				cxt->ckconstraints = lappend(cxt->ckconstraints, constraint);
 				break;
@@ -629,6 +692,14 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 					 constraint->contype);
 				break;
 		}
+
+		if (saw_default && saw_identity)
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+					 errmsg("both default and identity specified for column \"%s\" of table \"%s\"",
+							column->colname, cxt->relation->relname),
+					 parser_errposition(cxt->pstate,
+										constraint->location)));
 	}
 
 	/*
@@ -876,6 +947,29 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 			def->cooked_default = this_default;
 		}
 
+		/*
+		 * Copy identity if requested
+		 */
+		if (attribute->attidentity != ' ' &&
+			(table_like_clause->options & CREATE_TABLE_LIKE_IDENTITY))
+		{
+			List       *seqlist;
+			Oid         seq_relid;
+			List	   *seq_options;
+			char	   *snamespace;
+			char	   *sname;
+
+			/*
+			 * find sequence owned by old column; extract sequence parameters;
+			 * build new default and create sequence commands
+			 */
+			seqlist = getOwnedSequences(RelationGetRelid(relation), attribute->attnum);
+			seq_relid = linitial_oid(seqlist);
+			seq_options = sequence_options(seq_relid);
+			generateSerialExtraStmts(cxt, def, seq_options, DEPENDENCY_INTERNAL, &snamespace, &sname);
+			def->raw_default = (Node *) generateNextvalExpr(snamespace, sname);
+		}
+
 		/* Likewise, copy storage if requested */
 		if (table_like_clause->options & CREATE_TABLE_LIKE_STORAGE)
 			def->storage = attribute->attstorage;
@@ -2605,6 +2699,33 @@ transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
 					break;
 				}
 
+			case AT_AddIdentity:
+				{
+					Constraint  *def = (Constraint *) cmd->def;
+					ColumnDef *newdef = makeNode(ColumnDef);
+					Oid			typeOid;
+					char	   *snamespace;
+					char	   *sname;
+
+					Assert(IsA(def, Constraint));
+
+					typeOid = get_atttype(relid, get_attnum(relid, cmd->name));
+					if (!(typeOid == INT2OID || typeOid == INT4OID || typeOid == INT8OID))
+						ereport(ERROR,
+								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+								 errmsg("identity column type must be smallint, integer, or bigint")));
+
+					newdef->colname = cmd->name;  // XXX before below FIXME
+					generateSerialExtraStmts(&cxt, newdef, def->options, DEPENDENCY_INTERNAL, &snamespace, &sname);
+					newdef->raw_default = (Node *) generateNextvalExpr(snamespace, sname);
+					newdef->identity = def->generated_when;
+
+					cmd->def = (Node *) newdef;
+
+					newcmds = lappend(newcmds, cmd);
+					break;
+				}
+
 			default:
 				newcmds = lappend(newcmds, cmd);
 				break;
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index a22a11e..a9652f4 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -61,6 +61,7 @@ static Query *rewriteRuleAction(Query *parsetree,
 static List *adjustJoinTreeList(Query *parsetree, bool removert, int rt_index);
 static List *rewriteTargetListIU(List *targetList,
 					CmdType commandType,
+								 OverridingKind override,
 					Relation target_relation,
 					int result_rti,
 					List **attrno_list);
@@ -696,6 +697,7 @@ adjustJoinTreeList(Query *parsetree, bool removert, int rt_index)
 static List *
 rewriteTargetListIU(List *targetList,
 					CmdType commandType,
+					OverridingKind override,
 					Relation target_relation,
 					int result_rti,
 					List **attrno_list)
@@ -776,6 +778,7 @@ rewriteTargetListIU(List *targetList,
 	for (attrno = 1; attrno <= numattrs; attrno++)
 	{
 		TargetEntry *new_tle = new_tles[attrno - 1];
+		bool	apply_default;
 
 		att_tup = target_relation->rd_att->attrs[attrno - 1];
 
@@ -788,8 +791,37 @@ rewriteTargetListIU(List *targetList,
 		 * it's an INSERT and there's no tlist entry for the column, or the
 		 * tlist entry is a DEFAULT placeholder node.
 		 */
-		if ((new_tle == NULL && commandType == CMD_INSERT) ||
-			(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)))
+		apply_default =((new_tle == NULL && commandType == CMD_INSERT) ||
+						(new_tle && new_tle->expr && IsA(new_tle->expr, SetToDefault)));
+
+		if (commandType == CMD_INSERT)
+		{
+			if (att_tup->attidentity == CONSTR_GENERATED_ALWAYS && !apply_default)
+			{
+				if (override != OVERRIDING_SYSTEM_VALUE)
+					ereport(ERROR,
+							(errcode(ERRCODE_GENERATED_ALWAYS),
+							 errmsg("cannot insert into column \"%s\"", NameStr(att_tup->attname)),
+							 errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
+									   NameStr(att_tup->attname)),
+							 errhint("Use OVERRIDING SYSTEM VALUE to override.")));
+			}
+
+			if (att_tup->attidentity == CONSTR_GENERATED_DEFAULT && override == OVERRIDING_USER_VALUE)
+				apply_default = true;
+		}
+
+		if (commandType == CMD_UPDATE)
+		{
+			if (att_tup->attidentity == CONSTR_GENERATED_ALWAYS && !apply_default)
+				ereport(ERROR,
+						(errcode(ERRCODE_GENERATED_ALWAYS),
+						 errmsg("column \"%s\" can only be updated to DEFAULT", NameStr(att_tup->attname)),
+						 errdetail("Column \"%s\" is an identity column defined as GENERATED ALWAYS.",
+								   NameStr(att_tup->attname))));
+		}
+
+		if (apply_default)
 		{
 			Node	   *new_expr;
 
@@ -3214,6 +3246,7 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 				/* Process the main targetlist ... */
 				parsetree->targetList = rewriteTargetListIU(parsetree->targetList,
 													  parsetree->commandType,
+															parsetree->override,
 															rt_entry_relation,
 												   parsetree->resultRelation,
 															&attrnos);
@@ -3226,6 +3259,7 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 				parsetree->targetList =
 					rewriteTargetListIU(parsetree->targetList,
 										parsetree->commandType,
+										parsetree->override,
 										rt_entry_relation,
 										parsetree->resultRelation, NULL);
 			}
@@ -3236,6 +3270,7 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 				parsetree->onConflict->onConflictSet =
 					rewriteTargetListIU(parsetree->onConflict->onConflictSet,
 										CMD_UPDATE,
+										parsetree->override,
 										rt_entry_relation,
 										parsetree->resultRelation,
 										NULL);
@@ -3245,7 +3280,9 @@ RewriteQuery(Query *parsetree, List *rewrite_events)
 		{
 			parsetree->targetList =
 				rewriteTargetListIU(parsetree->targetList,
-									parsetree->commandType, rt_entry_relation,
+									parsetree->commandType,
+									parsetree->override,
+									rt_entry_relation,
 									parsetree->resultRelation, NULL);
 			rewriteTargetListUD(parsetree, rt_entry, rt_entry_relation);
 		}
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 8a81d7a..fb3aa78 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -5605,6 +5605,14 @@ get_insert_query_def(Query *query, deparse_context *context)
 	if (query->targetList)
 		appendStringInfoString(buf, ") ");
 
+	if (query->override)
+	{
+		if (query->override == OVERRIDING_SYSTEM_VALUE)
+			appendStringInfoString(buf, "OVERRIDING SYSTEM VALUE ");
+		else if (query->override == OVERRIDING_USER_VALUE)
+			appendStringInfoString(buf, "OVERRIDING USER VALUE ");
+	}
+
 	if (select_rte)
 	{
 		/* Add the SELECT */
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 8d2ad01..78c31d1 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -2937,6 +2937,7 @@ RelationBuildLocalRelation(const char *relname,
 	has_not_null = false;
 	for (i = 0; i < natts; i++)
 	{
+		rel->rd_att->attrs[i]->attidentity = tupDesc->attrs[i]->attidentity;
 		rel->rd_att->attrs[i]->attnotnull = tupDesc->attrs[i]->attnotnull;
 		has_not_null |= tupDesc->attrs[i]->attnotnull;
 	}
diff --git a/src/backend/utils/errcodes.txt b/src/backend/utils/errcodes.txt
index be924d5..fbda6c4 100644
--- a/src/backend/utils/errcodes.txt
+++ b/src/backend/utils/errcodes.txt
@@ -326,6 +326,7 @@ Section: Class 42 - Syntax Error or Access Rule Violation
 42P21    E    ERRCODE_COLLATION_MISMATCH                                     collation_mismatch
 42P22    E    ERRCODE_INDETERMINATE_COLLATION                                indeterminate_collation
 42809    E    ERRCODE_WRONG_OBJECT_TYPE                                      wrong_object_type
+428C9    E    ERRCODE_GENERATED_ALWAYS                                       generated_always
 
 # Note: for ERRCODE purposes, we divide namable objects into these categories:
 # databases, schemas, prepared statements, cursors, tables, columns,
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index a5c2d09..1c3ff12 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1883,6 +1883,9 @@ dumpTableData_insert(Archive *fout, void *dcontext)
 						appendPQExpBufferStr(insertStmt, ") ");
 					}
 
+					if (tbinfo->needs_override)
+						appendPQExpBufferStr(insertStmt, "OVERRIDING SYSTEM VALUE ");
+
 					appendPQExpBufferStr(insertStmt, "VALUES (");
 				}
 			}
@@ -5194,6 +5197,7 @@ getTables(Archive *fout, int *numTables)
 	int			i_toastreloptions;
 	int			i_reloftype;
 	int			i_relpages;
+	int			i_is_identity_sequence;
 	int			i_changed_acl;
 
 	/* Make sure we are in proper schema */
@@ -5270,6 +5274,7 @@ getTables(Archive *fout, int *numTables)
 						  "CASE WHEN 'check_option=local' = ANY (c.reloptions) THEN 'LOCAL'::text "
 						  "WHEN 'check_option=cascaded' = ANY (c.reloptions) THEN 'CASCADED'::text ELSE NULL END AS checkoption, "
 						  "tc.reloptions AS toast_reloptions, "
+						  "EXISTS (SELECT 1 FROM pg_depend WHERE classid = 'pg_class'::regclass AND objid = c.oid AND objsubid = 0 AND refclassid = 'pg_attrdef'::regclass AND deptype = 'i') AS is_identity_sequence, "
 						  "EXISTS (SELECT 1 FROM pg_attribute at LEFT JOIN pg_init_privs pip ON "
 						  "(c.oid = pip.objoid "
 						  "AND pip.classoid = 'pg_class'::regclass "
@@ -5867,6 +5872,7 @@ getTables(Archive *fout, int *numTables)
 	i_checkoption = PQfnumber(res, "checkoption");
 	i_toastreloptions = PQfnumber(res, "toast_reloptions");
 	i_reloftype = PQfnumber(res, "reloftype");
+	i_is_identity_sequence = PQfnumber(res, "is_identity_sequence");
 	i_changed_acl = PQfnumber(res, "changed_acl");
 
 	if (dopt->lockWaitTimeout && fout->remoteVersion >= 70300)
@@ -5968,6 +5974,8 @@ getTables(Archive *fout, int *numTables)
 
 		tblinfo[i].postponed_def = false;		/* might get set during sort */
 
+		tblinfo[i].is_identity_sequence = (strcmp(PQgetvalue(res, i, i_is_identity_sequence), "t") == 0);
+
 		/*
 		 * Read-lock target tables to make sure they aren't DROPPED or altered
 		 * in schema before we get around to dumping them.
@@ -7651,6 +7659,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	int			i_typstorage;
 	int			i_attnotnull;
 	int			i_atthasdef;
+	int			i_attidentity;
 	int			i_attisdropped;
 	int			i_attlen;
 	int			i_attalign;
@@ -7696,7 +7705,34 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 
 		resetPQExpBuffer(q);
 
-		if (fout->remoteVersion >= 90200)
+		if (fout->remoteVersion >= 100000)
+		{
+			/*
+			 * attidenity is new in version 10.
+			 */
+			appendPQExpBuffer(q, "SELECT a.attnum, a.attname, a.atttypmod, "
+							  "a.attstattarget, a.attstorage, t.typstorage, "
+							  "a.attnotnull, a.atthasdef, a.attisdropped, "
+							  "a.attlen, a.attalign, a.attislocal, "
+				  "pg_catalog.format_type(t.oid,a.atttypmod) AS atttypname, "
+						"array_to_string(a.attoptions, ', ') AS attoptions, "
+							  "CASE WHEN a.attcollation <> t.typcollation "
+						   "THEN a.attcollation ELSE 0 END AS attcollation, "
+							  "a.attidentity, "
+							  "pg_catalog.array_to_string(ARRAY("
+							  "SELECT pg_catalog.quote_ident(option_name) || "
+							  "' ' || pg_catalog.quote_literal(option_value) "
+						"FROM pg_catalog.pg_options_to_table(attfdwoptions) "
+							  "ORDER BY option_name"
+							  "), E',\n    ') AS attfdwoptions "
+			 "FROM pg_catalog.pg_attribute a LEFT JOIN pg_catalog.pg_type t "
+							  "ON a.atttypid = t.oid "
+							  "WHERE a.attrelid = '%u'::pg_catalog.oid "
+							  "AND a.attnum > 0::pg_catalog.int2 "
+							  "ORDER BY a.attrelid, a.attnum",
+							  tbinfo->dobj.catId.oid);
+		}
+		else if (fout->remoteVersion >= 90200)
 		{
 			/*
 			 * attfdwoptions is new in 9.2.
@@ -7838,6 +7874,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		i_typstorage = PQfnumber(res, "typstorage");
 		i_attnotnull = PQfnumber(res, "attnotnull");
 		i_atthasdef = PQfnumber(res, "atthasdef");
+		i_attidentity = PQfnumber(res, "attidentity");
 		i_attisdropped = PQfnumber(res, "attisdropped");
 		i_attlen = PQfnumber(res, "attlen");
 		i_attalign = PQfnumber(res, "attalign");
@@ -7853,6 +7890,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attstattarget = (int *) pg_malloc(ntups * sizeof(int));
 		tbinfo->attstorage = (char *) pg_malloc(ntups * sizeof(char));
 		tbinfo->typstorage = (char *) pg_malloc(ntups * sizeof(char));
+		tbinfo->attidentity = (char *) pg_malloc(ntups * sizeof(bool));
 		tbinfo->attisdropped = (bool *) pg_malloc(ntups * sizeof(bool));
 		tbinfo->attlen = (int *) pg_malloc(ntups * sizeof(int));
 		tbinfo->attalign = (char *) pg_malloc(ntups * sizeof(char));
@@ -7877,6 +7915,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			tbinfo->attstattarget[j] = atoi(PQgetvalue(res, j, i_attstattarget));
 			tbinfo->attstorage[j] = *(PQgetvalue(res, j, i_attstorage));
 			tbinfo->typstorage[j] = *(PQgetvalue(res, j, i_typstorage));
+			tbinfo->attidentity[j] = *(PQgetvalue(res, j, i_attidentity));
+			tbinfo->needs_override = tbinfo->needs_override || (tbinfo->attidentity[j] == 'a');
 			tbinfo->attisdropped[j] = (PQgetvalue(res, j, i_attisdropped)[0] == 't');
 			tbinfo->attlen[j] = atoi(PQgetvalue(res, j, i_attlen));
 			tbinfo->attalign[j] = *(PQgetvalue(res, j, i_attalign));
@@ -7952,6 +7992,9 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 			{
 				int			adnum;
 
+				if (tbinfo->attidentity[j] != ' ')
+					continue;
+
 				adnum = atoi(PQgetvalue(res, j, 2));
 
 				if (adnum <= 0 || adnum > ntups)
@@ -16404,10 +16447,13 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	/*
 	 * DROP must be fully qualified in case same name appears in pg_catalog
 	 */
-	appendPQExpBuffer(delqry, "DROP SEQUENCE %s.",
-					  fmtId(tbinfo->dobj.namespace->dobj.name));
-	appendPQExpBuffer(delqry, "%s;\n",
-					  fmtId(tbinfo->dobj.name));
+	if (!tbinfo->is_identity_sequence)
+	{
+		appendPQExpBuffer(delqry, "DROP SEQUENCE %s.",
+						  fmtId(tbinfo->dobj.namespace->dobj.name));
+		appendPQExpBuffer(delqry, "%s;\n",
+						  fmtId(tbinfo->dobj.name));
+	}
 
 	resetPQExpBuffer(query);
 
@@ -16419,9 +16465,26 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 												tbinfo->dobj.catId.oid);
 	}
 
-	appendPQExpBuffer(query,
-					  "CREATE SEQUENCE %s\n",
-					  fmtId(tbinfo->dobj.name));
+	if (tbinfo->is_identity_sequence)
+	{
+		TableInfo  *owning_tab = findTableByOid(tbinfo->owning_tab);
+
+		appendPQExpBuffer(query,
+						  "ALTER TABLE %s ",
+						  fmtId(owning_tab->dobj.name));
+		appendPQExpBuffer(query,
+						  "ALTER COLUMN %s ADD GENERATED ",
+						  fmtId(owning_tab->attnames[tbinfo->owning_col - 1]));
+		if (owning_tab->attidentity[tbinfo->owning_col - 1] == 'a')
+			appendPQExpBuffer(query, "ALWAYS");
+		else if (owning_tab->attidentity[tbinfo->owning_col - 1] == 'd')
+			appendPQExpBuffer(query, "BY DEFAULT");
+		appendPQExpBuffer(query, " AS IDENTITY (\n");
+	}
+	else
+		appendPQExpBuffer(query,
+						  "CREATE SEQUENCE %s\n",
+						  fmtId(tbinfo->dobj.name));
 
 	if (fout->remoteVersion >= 80400)
 		appendPQExpBuffer(query, "    START WITH %s\n", startv);
@@ -16442,7 +16505,10 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 					  "    CACHE %s%s",
 					  cache, (cycled ? "\n    CYCLE" : ""));
 
-	appendPQExpBufferStr(query, ";\n");
+	if (tbinfo->is_identity_sequence)
+		appendPQExpBufferStr(query, "\n);\n");
+	else
+		appendPQExpBufferStr(query, ";\n");
 
 	appendPQExpBuffer(labelq, "SEQUENCE %s", fmtId(tbinfo->dobj.name));
 
@@ -16475,7 +16541,7 @@ dumpSequence(Archive *fout, TableInfo *tbinfo)
 	 * We need not schema-qualify the table reference because both sequence
 	 * and table must be in the same schema.
 	 */
-	if (OidIsValid(tbinfo->owning_tab))
+	if (OidIsValid(tbinfo->owning_tab) && !tbinfo->is_identity_sequence)
 	{
 		TableInfo  *owning_tab = findTableByOid(tbinfo->owning_tab);
 
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 2bfa2d9..f23d178 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -283,6 +283,7 @@ typedef struct _tableInfo
 	/* these two are set only if table is a sequence owned by a column: */
 	Oid			owning_tab;		/* OID of table owning sequence */
 	int			owning_col;		/* attr # of column owning sequence */
+	bool		is_identity_sequence;
 	int			relpages;		/* table's size in pages (from pg_class) */
 
 	bool		interesting;	/* true if need to collect more data */
@@ -300,6 +301,7 @@ typedef struct _tableInfo
 	char	   *attstorage;		/* attribute storage scheme */
 	char	   *typstorage;		/* type storage scheme */
 	bool	   *attisdropped;	/* true if attr is dropped; don't dump it */
+	char	   *attidentity;
 	int		   *attlen;			/* attribute length, used by binary_upgrade */
 	char	   *attalign;		/* attribute align, used by binary_upgrade */
 	bool	   *attislocal;		/* true if attr has local definition */
@@ -310,6 +312,7 @@ typedef struct _tableInfo
 	bool	   *inhNotNull;		/* true if NOT NULL is inherited */
 	struct _attrDefInfo **attrdefs;		/* DEFAULT expressions */
 	struct _constraintInfo *checkexprs; /* CHECK constraints */
+	bool		needs_override;	/* has GENERATED ALWAYS AS IDENTITY */
 
 	/*
 	 * Stuff computed only for dumpable tables.
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 6275a68..7dc97eb 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -140,7 +140,7 @@ describeAccessMethods(const char *pattern, bool verbose)
 	printQueryOpt myopt = pset.popt;
 	static const bool translate_columns[] = {false, true, false, false};
 
-	if (pset.sversion < 90600)
+	if (pset.sversion < 100000)
 	{
 		char		sverbuf[32];
 
@@ -1547,6 +1547,10 @@ describeOneTableDetails(const char *schemaname,
 							 "   WHERE c.oid = a.attcollation AND t.oid = a.atttypid AND a.attcollation <> t.typcollation) AS attcollation");
 	else
 		appendPQExpBufferStr(&buf, "\n  NULL AS attcollation");
+	if (pset.sversion >= 90600)
+		appendPQExpBufferStr(&buf, ", a.attidentity");
+	else
+		appendPQExpBufferStr(&buf, ", NULL AS attidentity");
 	if (tableinfo.relkind == 'i')
 		appendPQExpBufferStr(&buf, ",\n  pg_catalog.pg_get_indexdef(a.attrelid, a.attnum, TRUE) AS indexdef");
 	else
@@ -1709,9 +1713,11 @@ describeOneTableDetails(const char *schemaname,
 		/* Type */
 		printTableAddCell(&cont, PQgetvalue(res, i, 1), false, false);
 
-		/* Modifiers: collate, not null, default */
+		/* Modifiers: collate, not null, default, identity */
 		if (show_modifiers)
 		{
+			char   *identity;
+
 			resetPQExpBuffer(&tmpbuf);
 
 			if (!PQgetisnull(res, i, 5))
@@ -1740,6 +1746,17 @@ describeOneTableDetails(const char *schemaname,
 								  PQgetvalue(res, i, 2));
 			}
 
+			identity = PQgetvalue(res, i, 6);
+			if (strlen(identity) != 0 && (identity[0] == 'a' || identity[0] == 'd'))
+			{
+				if (tmpbuf.len > 0)
+					appendPQExpBufferChar(&tmpbuf, ' ');
+				if (identity[0] == 'a')
+					appendPQExpBuffer(&tmpbuf, " generated always as identity");
+				else if (identity[0] == 'd')
+					appendPQExpBuffer(&tmpbuf, " generated by default as identity");
+			}
+
 			modifiers[i] = pg_strdup(tmpbuf.data);
 			printTableAddCell(&cont, modifiers[i], false, false);
 		}
@@ -1750,16 +1767,16 @@ describeOneTableDetails(const char *schemaname,
 
 		/* Expression for index column */
 		if (tableinfo.relkind == 'i')
-			printTableAddCell(&cont, PQgetvalue(res, i, 6), false, false);
+			printTableAddCell(&cont, PQgetvalue(res, i, 7), false, false);
 
 		/* FDW options for foreign table column, only for 9.2 or later */
 		if (tableinfo.relkind == 'f' && pset.sversion >= 90200)
-			printTableAddCell(&cont, PQgetvalue(res, i, 7), false, false);
+			printTableAddCell(&cont, PQgetvalue(res, i, 8), false, false);
 
 		/* Storage and Description */
 		if (verbose)
 		{
-			int			firstvcol = 8;
+			int			firstvcol = 9;
 			char	   *storage = PQgetvalue(res, i, firstvcol);
 
 			/* these strings are literal in our syntax, so not translated. */
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index c04edad..e881764 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201608231
+#define CATALOG_VERSION_NO	201608262
 
 #endif
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 09b36c5..96b519b 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -236,7 +236,7 @@ extern bool sequenceIsOwned(Oid seqId, Oid *tableId, int32 *colId);
 
 extern void markSequenceUnowned(Oid seqId);
 
-extern List *getOwnedSequences(Oid relid);
+extern List *getOwnedSequences(Oid relid, AttrNumber attnum);
 
 extern Oid	get_constraint_index(Oid constraintId);
 
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index 39d8eed..6406b07 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -133,6 +133,9 @@ CATALOG(pg_attribute,1249) BKI_BOOTSTRAP BKI_WITHOUT_OIDS BKI_ROWTYPE_OID(75) BK
 	/* Has DEFAULT value or not */
 	bool		atthasdef;
 
+	/* 'a', 'd', or ' ' */
+	char		attidentity;
+
 	/* Is dropped (ie, logically invisible) or not */
 	bool		attisdropped;
 
@@ -188,7 +191,7 @@ typedef FormData_pg_attribute *Form_pg_attribute;
  * ----------------
  */
 
-#define Natts_pg_attribute				21
+#define Natts_pg_attribute				22
 #define Anum_pg_attribute_attrelid		1
 #define Anum_pg_attribute_attname		2
 #define Anum_pg_attribute_atttypid		3
@@ -203,13 +206,14 @@ typedef FormData_pg_attribute *Form_pg_attribute;
 #define Anum_pg_attribute_attalign		12
 #define Anum_pg_attribute_attnotnull	13
 #define Anum_pg_attribute_atthasdef		14
-#define Anum_pg_attribute_attisdropped	15
-#define Anum_pg_attribute_attislocal	16
-#define Anum_pg_attribute_attinhcount	17
-#define Anum_pg_attribute_attcollation	18
-#define Anum_pg_attribute_attacl		19
-#define Anum_pg_attribute_attoptions	20
-#define Anum_pg_attribute_attfdwoptions 21
+#define Anum_pg_attribute_attidentity	15
+#define Anum_pg_attribute_attisdropped	16
+#define Anum_pg_attribute_attislocal	17
+#define Anum_pg_attribute_attinhcount	18
+#define Anum_pg_attribute_attcollation	19
+#define Anum_pg_attribute_attacl		20
+#define Anum_pg_attribute_attoptions	21
+#define Anum_pg_attribute_attfdwoptions 22
 
 
 /* ----------------
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index e57b81c..0c9167d 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -145,7 +145,7 @@ typedef FormData_pg_class *Form_pg_class;
  */
 DATA(insert OID = 1247 (  pg_type		PGNSP 71 0 PGUID 0 0 0 0 0 0 0 f f p r 30 0 t f f f f f f t n 3 1 _null_ _null_ ));
 DESCR("");
-DATA(insert OID = 1249 (  pg_attribute	PGNSP 75 0 PGUID 0 0 0 0 0 0 0 f f p r 21 0 f f f f f f f t n 3 1 _null_ _null_ ));
+DATA(insert OID = 1249 (  pg_attribute	PGNSP 75 0 PGUID 0 0 0 0 0 0 0 f f p r 22 0 f f f f f f f t n 3 1 _null_ _null_ ));
 DESCR("");
 DATA(insert OID = 1255 (  pg_proc		PGNSP 81 0 PGUID 0 0 0 0 0 0 0 f f p r 29 0 t f f f f f f t n 3 1 _null_ _null_ ));
 DESCR("");
diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h
index 6af60d8..a85982d 100644
--- a/src/include/commands/sequence.h
+++ b/src/include/commands/sequence.h
@@ -71,6 +71,7 @@ extern Datum setval_oid(PG_FUNCTION_ARGS);
 extern Datum setval3_oid(PG_FUNCTION_ARGS);
 extern Datum lastval(PG_FUNCTION_ARGS);
 
+extern List *sequence_options(Oid relid);
 extern Datum pg_sequence_parameters(PG_FUNCTION_ARGS);
 
 extern ObjectAddress DefineSequence(CreateSeqStmt *stmt);
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 1481fff..4af485f 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -25,6 +25,13 @@
 #include "nodes/primnodes.h"
 #include "nodes/value.h"
 
+typedef enum OverridingKind
+{
+	OVERRIDING_NOT_SET = 0,
+	OVERRIDING_USER_VALUE,
+	OVERRIDING_SYSTEM_VALUE
+} OverridingKind;
+
 /* Possible sources of a Query */
 typedef enum QuerySource
 {
@@ -130,6 +137,8 @@ typedef struct Query
 
 	List	   *targetList;		/* target list (of TargetEntry) */
 
+	OverridingKind override;	/* OVERRIDING clause */
+
 	OnConflictExpr *onConflict; /* ON CONFLICT DO [NOTHING | UPDATE] */
 
 	List	   *returningList;	/* return-values list (of TargetEntry) */
@@ -595,6 +604,7 @@ typedef struct ColumnDef
 	char		storage;		/* attstorage setting, or 0 for default */
 	Node	   *raw_default;	/* default value (untransformed parse tree) */
 	Node	   *cooked_default; /* default value (transformed expr tree) */
+	char		identity;		/* attidentity setting */
 	CollateClause *collClause;	/* untransformed COLLATE spec, if any */
 	Oid			collOid;		/* collation OID (InvalidOid if not set) */
 	List	   *constraints;	/* other constraints on column */
@@ -616,9 +626,10 @@ typedef enum TableLikeOption
 {
 	CREATE_TABLE_LIKE_DEFAULTS = 1 << 0,
 	CREATE_TABLE_LIKE_CONSTRAINTS = 1 << 1,
-	CREATE_TABLE_LIKE_INDEXES = 1 << 2,
-	CREATE_TABLE_LIKE_STORAGE = 1 << 3,
-	CREATE_TABLE_LIKE_COMMENTS = 1 << 4,
+	CREATE_TABLE_LIKE_IDENTITY = 1 << 2,
+	CREATE_TABLE_LIKE_INDEXES = 1 << 3,
+	CREATE_TABLE_LIKE_STORAGE = 1 << 4,
+	CREATE_TABLE_LIKE_COMMENTS = 1 << 5,
 	CREATE_TABLE_LIKE_ALL = PG_INT32_MAX
 } TableLikeOption;
 
@@ -1224,6 +1235,7 @@ typedef struct InsertStmt
 	OnConflictClause *onConflictClause; /* ON CONFLICT clause */
 	List	   *returningList;	/* list of expressions to return */
 	WithClause *withClause;		/* WITH clause */
+	OverridingKind override;	/* OVERRIDING clause */
 } InsertStmt;
 
 /* ----------------------
@@ -1525,7 +1537,9 @@ typedef enum AlterTableType
 	AT_DisableRowSecurity,		/* DISABLE ROW SECURITY */
 	AT_ForceRowSecurity,		/* FORCE ROW SECURITY */
 	AT_NoForceRowSecurity,		/* NO FORCE ROW SECURITY */
-	AT_GenericOptions			/* OPTIONS (...) */
+	AT_GenericOptions,			/* OPTIONS (...) */
+	AT_AddIdentity,
+	AT_DropIdentity
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
@@ -1796,6 +1810,7 @@ typedef enum ConstrType			/* types of constraints */
 								 * expect it */
 	CONSTR_NOTNULL,
 	CONSTR_DEFAULT,
+	CONSTR_IDENTITY,
 	CONSTR_CHECK,
 	CONSTR_PRIMARY,
 	CONSTR_UNIQUE,
@@ -1807,6 +1822,9 @@ typedef enum ConstrType			/* types of constraints */
 	CONSTR_ATTR_IMMEDIATE
 } ConstrType;
 
+#define CONSTR_GENERATED_ALWAYS		'a'
+#define CONSTR_GENERATED_DEFAULT	'd'
+
 /* Foreign key action codes */
 #define FKCONSTR_ACTION_NOACTION	'a'
 #define FKCONSTR_ACTION_RESTRICT	'r'
@@ -1834,6 +1852,7 @@ typedef struct Constraint
 	bool		is_no_inherit;	/* is constraint non-inheritable? */
 	Node	   *raw_expr;		/* expr, as untransformed parse tree */
 	char	   *cooked_expr;	/* expr, as nodeToString representation */
+	char		generated_when;
 
 	/* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
 	List	   *keys;			/* String nodes naming referenced column(s) */
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 17ffef5..c35a77f 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -171,6 +171,7 @@ PG_KEYWORD("from", FROM, RESERVED_KEYWORD)
 PG_KEYWORD("full", FULL, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("function", FUNCTION, UNRESERVED_KEYWORD)
 PG_KEYWORD("functions", FUNCTIONS, UNRESERVED_KEYWORD)
+PG_KEYWORD("generated", GENERATED, RESERVED_KEYWORD)
 PG_KEYWORD("global", GLOBAL, UNRESERVED_KEYWORD)
 PG_KEYWORD("grant", GRANT, RESERVED_KEYWORD)
 PG_KEYWORD("granted", GRANTED, UNRESERVED_KEYWORD)
@@ -281,6 +282,7 @@ PG_KEYWORD("outer", OUTER_P, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("over", OVER, UNRESERVED_KEYWORD)
 PG_KEYWORD("overlaps", OVERLAPS, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("overlay", OVERLAY, COL_NAME_KEYWORD)
+PG_KEYWORD("overriding", OVERRIDING, UNRESERVED_KEYWORD)
 PG_KEYWORD("owned", OWNED, UNRESERVED_KEYWORD)
 PG_KEYWORD("owner", OWNER, UNRESERVED_KEYWORD)
 PG_KEYWORD("parallel", PARALLEL, UNRESERVED_KEYWORD)
diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out
index 97edde1..869df7a 100644
--- a/src/test/regress/expected/create_table_like.out
+++ b/src/test/regress/expected/create_table_like.out
@@ -66,6 +66,32 @@ SELECT * FROM inhg; /* Two records with three columns in order x=x, xx=text, y=y
 (2 rows)
 
 DROP TABLE inhg;
+CREATE TABLE test_like_id_1 (a int GENERATED ALWAYS AS IDENTITY, b text);
+INSERT INTO test_like_id_1 (b) VALUES ('b1');
+SELECT * FROM test_like_id_1;
+ a | b  
+---+----
+ 1 | b1
+(1 row)
+
+CREATE TABLE test_like_id_2 (LIKE test_like_id_1);
+INSERT INTO test_like_id_2 (b) VALUES ('b2');
+ERROR:  null value in column "a" violates not-null constraint
+DETAIL:  Failing row contains (null, b2).
+SELECT * FROM test_like_id_2;  -- identity was not copied
+ a | b 
+---+---
+(0 rows)
+
+CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
+INSERT INTO test_like_id_3 (b) VALUES ('b3');
+SELECT * FROM test_like_id_3;  -- identity was copied and applied
+ a | b  
+---+----
+ 1 | b3
+(1 row)
+
+DROP TABLE test_like_id_1, test_like_id_2, test_like_id_3;
 CREATE TABLE inhg (x text, LIKE inhx INCLUDING INDEXES, y text); /* copies indexes */
 INSERT INTO inhg VALUES (5, 10);
 INSERT INTO inhg VALUES (20, 10); -- should fail
diff --git a/src/test/regress/expected/identity.out b/src/test/regress/expected/identity.out
new file mode 100644
index 0000000..1aed7c2
--- /dev/null
+++ b/src/test/regress/expected/identity.out
@@ -0,0 +1,177 @@
+CREATE TABLE itest1 (a int generated by default as identity, b text);
+CREATE TABLE itest2 (a bigint generated always as identity, b text);
+CREATE TABLE itest3 (a smallint generated by default as identity (start with 7 increment by 5), b text);
+ALTER TABLE itest3 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error
+ERROR:  column "a" of relation "itest3" is already an identity column
+CREATE TABLE itest4 (a int, b text);
+ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error
+ERROR:  column "a" of relation "itest4" is already an identity column
+ALTER TABLE itest4 ALTER COLUMN b ADD GENERATED ALWAYS AS IDENTITY;  -- error
+ERROR:  identity column type must be smallint, integer, or bigint
+-- invalid column type
+CREATE TABLE itest_err_1 (a text generated by default as identity);
+ERROR:  identity column type must be smallint, integer, or bigint
+-- duplicate identity
+CREATE TABLE itest_err_2 (a int generated always as identity generated by default as identity);
+ERROR:  multiple identity specifications for column "a" of table "itest_err_2"
+LINE 1: ...E itest_err_2 (a int generated always as identity generated ...
+                                                             ^
+-- cannot have default and identity
+CREATE TABLE itest_err_3 (a int default 5 generated by default as identity);
+ERROR:  both default and identity specified for column "a" of table "itest_err_3"
+LINE 1: CREATE TABLE itest_err_3 (a int default 5 generated by defau...
+                                                  ^
+-- cannot combine serial and identity
+CREATE TABLE itest_err_4 (a serial generated by default as identity);
+ERROR:  both default and identity specified for column "a" of table "itest_err_4"
+INSERT INTO itest1 DEFAULT VALUES;
+INSERT INTO itest1 DEFAULT VALUES;
+INSERT INTO itest2 DEFAULT VALUES;
+INSERT INTO itest2 DEFAULT VALUES;
+INSERT INTO itest3 DEFAULT VALUES;
+INSERT INTO itest3 DEFAULT VALUES;
+INSERT INTO itest4 DEFAULT VALUES;
+INSERT INTO itest4 DEFAULT VALUES;
+SELECT * FROM itest1;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+(2 rows)
+
+SELECT * FROM itest2;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+(2 rows)
+
+SELECT * FROM itest3;
+ a  | b 
+----+---
+  7 | 
+ 12 | 
+(2 rows)
+
+SELECT * FROM itest4;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+(2 rows)
+
+-- OVERRIDING tests
+INSERT INTO itest1 VALUES (10, 'xyz');
+INSERT INTO itest1 OVERRIDING USER VALUE VALUES (10, 'xyz');
+SELECT * FROM itest1;
+ a  |  b  
+----+-----
+  1 | 
+  2 | 
+ 10 | xyz
+  3 | xyz
+(4 rows)
+
+INSERT INTO itest2 VALUES (10, 'xyz');
+ERROR:  cannot insert into column "a"
+DETAIL:  Column "a" is an identity column defined as GENERATED ALWAYS.
+HINT:  Use OVERRIDING SYSTEM VALUE to override.
+INSERT INTO itest2 OVERRIDING SYSTEM VALUE VALUES (10, 'xyz');
+SELECT * FROM itest2;
+ a  |  b  
+----+-----
+  1 | 
+  2 | 
+ 10 | xyz
+(3 rows)
+
+-- UPDATE tests
+UPDATE itest1 SET a = 101 WHERE a = 1;
+UPDATE itest1 SET a = DEFAULT WHERE a = 2;
+SELECT * FROM itest1;
+  a  |  b  
+-----+-----
+  10 | xyz
+   3 | xyz
+ 101 | 
+   4 | 
+(4 rows)
+
+UPDATE itest2 SET a = 101 WHERE a = 1;
+ERROR:  column "a" can only be updated to DEFAULT
+DETAIL:  Column "a" is an identity column defined as GENERATED ALWAYS.
+UPDATE itest2 SET a = DEFAULT WHERE a = 2;
+SELECT * FROM itest2;
+ a  |  b  
+----+-----
+  1 | 
+ 10 | xyz
+  3 | 
+(3 rows)
+
+-- DROP IDENTITY tests
+ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;
+ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;  -- error
+ERROR:  column "a" of relation "itest4" is not an identity column
+INSERT INTO itest4 DEFAULT VALUES;
+SELECT * FROM itest4;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+   | 
+(3 rows)
+
+-- check that sequence is removed
+SELECT sequence_name FROM itest4_a_seq;
+ERROR:  relation "itest4_a_seq" does not exist
+LINE 1: SELECT sequence_name FROM itest4_a_seq;
+                                  ^
+-- test views
+CREATE TABLE itest10 (a int generated by default as identity, b text);
+CREATE TABLE itest11 (a int generated always as identity, b text);
+CREATE VIEW itestv10 AS SELECT * FROM itest10;
+CREATE VIEW itestv11 AS SELECT * FROM itest11;
+INSERT INTO itestv10 DEFAULT VALUES;
+INSERT INTO itestv10 DEFAULT VALUES;
+INSERT INTO itestv11 DEFAULT VALUES;
+INSERT INTO itestv11 DEFAULT VALUES;
+SELECT * FROM itestv10;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+(2 rows)
+
+SELECT * FROM itestv11;
+ a | b 
+---+---
+ 1 | 
+ 2 | 
+(2 rows)
+
+INSERT INTO itestv10 VALUES (10, 'xyz');
+INSERT INTO itestv10 OVERRIDING USER VALUE VALUES (11, 'xyz');
+SELECT * FROM itestv10;
+ a  |  b  
+----+-----
+  1 | 
+  2 | 
+ 10 | xyz
+  3 | xyz
+(4 rows)
+
+INSERT INTO itestv11 VALUES (10, 'xyz');
+ERROR:  cannot insert into column "a"
+DETAIL:  Column "a" is an identity column defined as GENERATED ALWAYS.
+HINT:  Use OVERRIDING SYSTEM VALUE to override.
+INSERT INTO itestv11 OVERRIDING SYSTEM VALUE VALUES (11, 'xyz');
+SELECT * FROM itestv11;
+ a  |  b  
+----+-----
+  1 | 
+  2 | 
+ 11 | xyz
+(3 rows)
+
diff --git a/src/test/regress/expected/truncate.out b/src/test/regress/expected/truncate.out
index 5c5277e..c76a217 100644
--- a/src/test/regress/expected/truncate.out
+++ b/src/test/regress/expected/truncate.out
@@ -393,6 +393,36 @@ SELECT * FROM truncate_a;
   2 |  34
 (2 rows)
 
+CREATE TABLE truncate_b (id int GENERATED ALWAYS AS IDENTITY (START WITH 44));
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+ id 
+----
+ 44
+ 45
+(2 rows)
+
+TRUNCATE truncate_b;
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+ id 
+----
+ 46
+ 47
+(2 rows)
+
+TRUNCATE truncate_b RESTART IDENTITY;
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+ id 
+----
+ 44
+ 45
+(2 rows)
+
 -- check rollback of a RESTART IDENTITY operation
 BEGIN;
 TRUNCATE truncate_a RESTART IDENTITY;
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 1cb5dfc..d36e2b0 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -108,6 +108,11 @@ test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combo
 # ----------
 test: plancache limit plpgsql copy2 temp domain rangefuncs prepare without_oid conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml
 
+# ----------
+# Another group of parallel tests
+# ----------
+test: identity
+
 # event triggers cannot run concurrently with any test that runs DDL
 test: event_trigger
 
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 8958d8c..be5a76d 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -160,6 +160,7 @@ test: conversion
 test: truncate
 test: alter_table
 test: sequence
+test: identity
 test: polymorphism
 test: rowtypes
 test: returning
diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql
index 6dded1f..0cb994f 100644
--- a/src/test/regress/sql/create_table_like.sql
+++ b/src/test/regress/sql/create_table_like.sql
@@ -37,6 +37,17 @@ CREATE TABLE inhg (x text, LIKE inhx INCLUDING CONSTRAINTS, y text); /* Copies c
 SELECT * FROM inhg; /* Two records with three columns in order x=x, xx=text, y=y */
 DROP TABLE inhg;
 
+CREATE TABLE test_like_id_1 (a int GENERATED ALWAYS AS IDENTITY, b text);
+INSERT INTO test_like_id_1 (b) VALUES ('b1');
+SELECT * FROM test_like_id_1;
+CREATE TABLE test_like_id_2 (LIKE test_like_id_1);
+INSERT INTO test_like_id_2 (b) VALUES ('b2');
+SELECT * FROM test_like_id_2;  -- identity was not copied
+CREATE TABLE test_like_id_3 (LIKE test_like_id_1 INCLUDING IDENTITY);
+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 inhg (x text, LIKE inhx INCLUDING INDEXES, y text); /* copies indexes */
 INSERT INTO inhg VALUES (5, 10);
 INSERT INTO inhg VALUES (20, 10); -- should fail
diff --git a/src/test/regress/sql/identity.sql b/src/test/regress/sql/identity.sql
new file mode 100644
index 0000000..3fdd504
--- /dev/null
+++ b/src/test/regress/sql/identity.sql
@@ -0,0 +1,99 @@
+CREATE TABLE itest1 (a int generated by default as identity, b text);
+CREATE TABLE itest2 (a bigint generated always as identity, b text);
+CREATE TABLE itest3 (a smallint generated by default as identity (start with 7 increment by 5), b text);
+ALTER TABLE itest3 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error
+
+CREATE TABLE itest4 (a int, b text);
+ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;
+ALTER TABLE itest4 ALTER COLUMN a ADD GENERATED ALWAYS AS IDENTITY;  -- error
+ALTER TABLE itest4 ALTER COLUMN b ADD GENERATED ALWAYS AS IDENTITY;  -- error
+
+-- invalid column type
+CREATE TABLE itest_err_1 (a text generated by default as identity);
+
+-- duplicate identity
+CREATE TABLE itest_err_2 (a int generated always as identity generated by default as identity);
+
+-- cannot have default and identity
+CREATE TABLE itest_err_3 (a int default 5 generated by default as identity);
+
+-- cannot combine serial and identity
+CREATE TABLE itest_err_4 (a serial generated by default as identity);
+
+INSERT INTO itest1 DEFAULT VALUES;
+INSERT INTO itest1 DEFAULT VALUES;
+INSERT INTO itest2 DEFAULT VALUES;
+INSERT INTO itest2 DEFAULT VALUES;
+INSERT INTO itest3 DEFAULT VALUES;
+INSERT INTO itest3 DEFAULT VALUES;
+INSERT INTO itest4 DEFAULT VALUES;
+INSERT INTO itest4 DEFAULT VALUES;
+
+SELECT * FROM itest1;
+SELECT * FROM itest2;
+SELECT * FROM itest3;
+SELECT * FROM itest4;
+
+
+-- OVERRIDING tests
+
+INSERT INTO itest1 VALUES (10, 'xyz');
+INSERT INTO itest1 OVERRIDING USER VALUE VALUES (10, 'xyz');
+
+SELECT * FROM itest1;
+
+INSERT INTO itest2 VALUES (10, 'xyz');
+INSERT INTO itest2 OVERRIDING SYSTEM VALUE VALUES (10, 'xyz');
+
+SELECT * FROM itest2;
+
+
+-- UPDATE tests
+
+UPDATE itest1 SET a = 101 WHERE a = 1;
+UPDATE itest1 SET a = DEFAULT WHERE a = 2;
+SELECT * FROM itest1;
+
+UPDATE itest2 SET a = 101 WHERE a = 1;
+UPDATE itest2 SET a = DEFAULT WHERE a = 2;
+SELECT * FROM itest2;
+
+
+-- DROP IDENTITY tests
+
+ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;
+ALTER TABLE itest4 ALTER COLUMN a DROP IDENTITY;  -- error
+
+INSERT INTO itest4 DEFAULT VALUES;
+SELECT * FROM itest4;
+
+-- check that sequence is removed
+SELECT sequence_name FROM itest4_a_seq;
+
+
+-- test views
+
+CREATE TABLE itest10 (a int generated by default as identity, b text);
+CREATE TABLE itest11 (a int generated always as identity, b text);
+
+CREATE VIEW itestv10 AS SELECT * FROM itest10;
+CREATE VIEW itestv11 AS SELECT * FROM itest11;
+
+INSERT INTO itestv10 DEFAULT VALUES;
+INSERT INTO itestv10 DEFAULT VALUES;
+
+INSERT INTO itestv11 DEFAULT VALUES;
+INSERT INTO itestv11 DEFAULT VALUES;
+
+SELECT * FROM itestv10;
+SELECT * FROM itestv11;
+
+INSERT INTO itestv10 VALUES (10, 'xyz');
+INSERT INTO itestv10 OVERRIDING USER VALUE VALUES (11, 'xyz');
+
+SELECT * FROM itestv10;
+
+INSERT INTO itestv11 VALUES (10, 'xyz');
+INSERT INTO itestv11 OVERRIDING SYSTEM VALUE VALUES (11, 'xyz');
+
+SELECT * FROM itestv11;
diff --git a/src/test/regress/sql/truncate.sql b/src/test/regress/sql/truncate.sql
index a3d6f53..1aab021 100644
--- a/src/test/regress/sql/truncate.sql
+++ b/src/test/regress/sql/truncate.sql
@@ -202,6 +202,24 @@ CREATE TABLE truncate_a (id serial,
 INSERT INTO truncate_a DEFAULT VALUES;
 SELECT * FROM truncate_a;
 
+CREATE TABLE truncate_b (id int GENERATED ALWAYS AS IDENTITY (START WITH 44));
+
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+
+TRUNCATE truncate_b;
+
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+
+TRUNCATE truncate_b RESTART IDENTITY;
+
+INSERT INTO truncate_b DEFAULT VALUES;
+INSERT INTO truncate_b DEFAULT VALUES;
+SELECT * FROM truncate_b;
+
 -- check rollback of a RESTART IDENTITY operation
 BEGIN;
 TRUNCATE truncate_a RESTART IDENTITY;
