CLUSTER on partitioned index

From 521b91b2a5555f5688e88145714db1e990b803ea Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v3 1/3] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 167 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/nodes/parsenodes.h        |   5 +-
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 208 insertions(+), 53 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index b9450e7366..0476cfff72 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -172,6 +172,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 04d12a7ece..391e018bbd 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/progress.h"
@@ -72,6 +74,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -113,7 +118,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -124,14 +129,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -169,8 +166,32 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, stmt->options);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, stmt->options);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, stmt->options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -180,7 +201,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -204,25 +224,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
 
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						stmt->options | CLUOPT_RECHECK);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, stmt->options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -328,9 +330,10 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -374,8 +377,13 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -391,6 +399,14 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -459,6 +475,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -483,12 +502,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -560,10 +573,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1557,3 +1566,75 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					options | CLUOPT_RECHECK);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..07ef7fc1b7 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 17b4e335c6..c862662a78 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -3198,8 +3198,9 @@ typedef struct AlterSystemStmt
  */
 typedef enum ClusterOption
 {
-	CLUOPT_RECHECK = 1 << 0,	/* recheck relation state */
-	CLUOPT_VERBOSE = 1 << 1		/* print progress info */
+	CLUOPT_VERBOSE = 1 << 0,	/* print progress info */
+	CLUOPT_RECHECK = 1 << 1,	/* recheck relation state */
+	CLUOPT_RECHECK_ISCLUSTERED = 1 << 2,	/* recheck relation state for indisclustered */
 } ClusterOption;
 
 typedef struct ClusterStmt
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..e4448350e7 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+   relname   | relkind | ?column? 
+-------------+---------+----------
+ clstrpart   | p       | t
+ clstrpart1  | p       | t
+ clstrpart11 | r       | f
+ clstrpart12 | p       | t
+ clstrpart2  | r       | f
+ clstrpart3  | p       | t
+ clstrpart33 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+    indexrelid     | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..22225dc924 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From cbd643ad3cb19f500a2af9200234402acf2f0511 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v3 2/3] preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 11 +++++++++++
 src/test/regress/sql/cluster.sql      |  3 +++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 5ec225abe1..55d429971f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -603,7 +603,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e4448350e7..8f245da46d 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,17 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
+DROP TABLE clstrpart;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 22225dc924..b871ab53c3 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,9 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+DROP TABLE clstrpart;
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From f41adc43b9b27c7b8aec8c78297ad8042f5049e7 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v3 3/3] Propogate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 116 +++++++++++++++++---------
 src/backend/commands/indexcmds.c      |  20 +++++
 src/test/regress/expected/cluster.out |  43 ++++++++++
 src/test/regress/sql/cluster.sql      |  13 +++
 4 files changed, 154 insertions(+), 38 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 391e018bbd..1e36c47ec6 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -73,6 +73,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -489,65 +490,104 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered as clustered, and parents of other
+ * indexes as unclustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
+	ListCell	*lc, *lc2;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel),
+			ShareRowExclusiveLock, NULL);
 
 	/*
-	 * If the index is already marked clustered, no need to do anything.
+	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's chilren
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	if (OidIsValid(indexOid))
+
+	foreach(lc, inh)
 	{
-		if (get_index_isclustered(indexOid))
-			return;
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
+		List 		*indexes = RelationGetIndexList(thisrel);
+
+		foreach (lc2, indexes)
+		{
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			Oid		partoid = index_get_partition(thisrel, indexOid);
+
+			if (thisIndexOid == indexOid || partoid == thisIndexOid) // OidIsValid(partoid))
+			{
+				/* A child of the clustered index should be set clustered, too */
+				set_indisclustered(thisIndexOid, true, pg_index);
+			}
+			else
+			{
+				/* indexes which are not children of the clustered index are set unclustered */
+				set_indisclustered(thisIndexOid, false, pg_index);
+			}
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
+
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
 
+	list_free(inh);
+
 	/*
-	 * Check each index of the relation and set/clear the bit as needed.
+	 * When setting an index partition unclustered, also remove
+	 * indisclustered from its parents
+	 * use this instead? get_partition_ancestors()
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
 
-	foreach(index, RelationGetIndexList(rel))
+	foreach (lc, RelationGetIndexList(rel))
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
+		Oid	thisIndexOid = lfirst_oid(lc);
 
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		if (thisIndexOid == indexOid)
+			continue;
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		while (get_rel_relispartition(thisIndexOid))
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
 		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
-
-		heap_freetuple(indexTuple);
 	}
 
 	table_close(pg_index, RowExclusiveLock);
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 67bd9b12dc..206eb4d656 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -26,12 +26,14 @@
 #include "catalog/index.h"
 #include "catalog/indexing.h"
 #include "catalog/pg_am.h"
+#include "catalog/partition.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
 #include "catalog/pg_opclass.h"
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
@@ -3773,6 +3775,24 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/* if the attached index is not clustered, invalidate all parents cluster mark, if any */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 8f245da46d..91d0c03055 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -505,6 +505,49 @@ Partition of: clstrpart FOR VALUES FROM (30) TO (40)
 Indexes:
     "clstrpart4_a_idx" btree (a) CLUSTER
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 5 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 5 (Use \d+ to list them.)
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx_2;
+ERROR:  index "clstrpart_idx_2" for table "clstrpart" does not exist
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a) CLUSTER
+    "clstrpart1_idx_2" btree (a)
+Number of partitions: 2 (Use \d+ to list them.)
+
 DROP TABLE clstrpart;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index b871ab53c3..635df97257 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -222,6 +222,19 @@ CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
 CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
 \d clstrpart4
+-- Check that attaching an unclustered index marks the parent unclustered:
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that only one child is marked clustered after marking clustered on a different parent
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx_2;
+\d clstrpart1
 DROP TABLE clstrpart;
 
 -- Test CLUSTER with external tuplesorting
-- 
2.17.0

From 75690aacef0d294e2667bd1091cf647dc9f5d187 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v4 1/5] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 167 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/nodes/parsenodes.h        |   5 +-
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 208 insertions(+), 53 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index b9450e7366..0476cfff72 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -172,6 +172,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 04d12a7ece..391e018bbd 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/progress.h"
@@ -72,6 +74,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -113,7 +118,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -124,14 +129,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -169,8 +166,32 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, stmt->options);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, stmt->options);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, stmt->options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -180,7 +201,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -204,25 +224,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
 
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						stmt->options | CLUOPT_RECHECK);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, stmt->options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -328,9 +330,10 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -374,8 +377,13 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -391,6 +399,14 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -459,6 +475,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -483,12 +502,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -560,10 +573,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1557,3 +1566,75 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					options | CLUOPT_RECHECK);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5238a960f7..07ef7fc1b7 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 53de31f3b1..087b1c7af6 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -3199,8 +3199,9 @@ typedef struct AlterSystemStmt
  */
 typedef enum ClusterOption
 {
-	CLUOPT_RECHECK = 1 << 0,	/* recheck relation state */
-	CLUOPT_VERBOSE = 1 << 1		/* print progress info */
+	CLUOPT_VERBOSE = 1 << 0,	/* print progress info */
+	CLUOPT_RECHECK = 1 << 1,	/* recheck relation state */
+	CLUOPT_RECHECK_ISCLUSTERED = 1 << 2,	/* recheck relation state for indisclustered */
 } ClusterOption;
 
 typedef struct ClusterStmt
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..e4448350e7 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+   relname   | relkind | ?column? 
+-------------+---------+----------
+ clstrpart   | p       | t
+ clstrpart1  | p       | t
+ clstrpart11 | r       | f
+ clstrpart12 | p       | t
+ clstrpart2  | r       | f
+ clstrpart3  | p       | t
+ clstrpart33 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+    indexrelid     | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..22225dc924 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From a3ab89d138c5b2a65b5b0900910d8e01b8a270ca Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v4 2/5] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 109 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 125 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 391e018bbd..4f30174ba7 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -73,6 +73,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -489,66 +490,88 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel), ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 54d90c28e7..538055c9a0 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e4448350e7..a9fb9f1021 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 22225dc924..d15bd51496 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 491f16c3e2750ccc4a1b57d9f906149f042e30a3 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v4 3/5] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 4f30174ba7..35beff6f9f 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -573,6 +573,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index a9fb9f1021..6d88978387 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index d15bd51496..c9bb204a93 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 068dde5053d185a7eb94a9b9f744e730dc546d98 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v4 4/5] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 538055c9a0..fd8b2d56d2 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -3775,6 +3775,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6d88978387..f0c962db75 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index c9bb204a93..ff7ffed6e4 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 0f14d0d9ea4c668fbdcbb57e8d4c9078352c4964 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v4 5/5] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index d1e120e5ae..af1565ec4c 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -603,7 +603,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index f0c962db75..fc642f87d2 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index ff7ffed6e4..5df338f60d 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 34944ed4a8e0313c7cb2c8eb996196ad9860b77d Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v5 2/7] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 167 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/nodes/parsenodes.h        |   5 +-
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 208 insertions(+), 53 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index b9450e7366..0476cfff72 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -172,6 +172,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 04d12a7ece..391e018bbd 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/progress.h"
@@ -72,6 +74,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -113,7 +118,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -124,14 +129,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -169,8 +166,32 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, stmt->options);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, stmt->options);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, stmt->options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -180,7 +201,6 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -204,25 +224,7 @@ cluster(ClusterStmt *stmt, bool isTopLevel)
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
 
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						stmt->options | CLUOPT_RECHECK);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, stmt->options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -328,9 +330,10 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -374,8 +377,13 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -391,6 +399,14 @@ cluster_rel(Oid tableOid, Oid indexOid, int options)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -459,6 +475,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -483,12 +502,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -560,10 +573,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1557,3 +1566,75 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					options | CLUOPT_RECHECK);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 8afc780acc..1deafd2707 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index d1f9ef29ca..43b6d16a13 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -3198,8 +3198,9 @@ typedef struct AlterSystemStmt
  */
 typedef enum ClusterOption
 {
-	CLUOPT_RECHECK = 1 << 0,	/* recheck relation state */
-	CLUOPT_VERBOSE = 1 << 1		/* print progress info */
+	CLUOPT_VERBOSE = 1 << 0,	/* print progress info */
+	CLUOPT_RECHECK = 1 << 1,	/* recheck relation state */
+	CLUOPT_RECHECK_ISCLUSTERED = 1 << 2,	/* recheck relation state for indisclustered */
 } ClusterOption;
 
 typedef struct ClusterStmt
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..e4448350e7 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+   relname   | relkind | ?column? 
+-------------+---------+----------
+ clstrpart   | p       | t
+ clstrpart1  | p       | t
+ clstrpart11 | r       | f
+ clstrpart12 | p       | t
+ clstrpart2  | r       | f
+ clstrpart3  | p       | t
+ clstrpart33 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+    indexrelid     | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..22225dc924 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 26723246af5b8bd48f85e6669822199511df05a5 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v5 3/7] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 109 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 125 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 391e018bbd..4f30174ba7 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -73,6 +73,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -489,66 +490,88 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel), ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index ca24620fd0..cd9ca1beff 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e4448350e7..a9fb9f1021 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 22225dc924..d15bd51496 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From c16bda5aa5dd18226b5348f7e259e9b7192e9e4f Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v5 4/7] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 4f30174ba7..35beff6f9f 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -573,6 +573,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index a9fb9f1021..6d88978387 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index d15bd51496..c9bb204a93 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From e8546faf5afbb8d23919d0631f2c9b7e714c2587 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v5 5/7] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index cd9ca1beff..fd18fe2584 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -3864,6 +3864,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6d88978387..f0c962db75 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index c9bb204a93..ff7ffed6e4 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 2be544396d452f3c05faf066d1fcc08ffadac025 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v5 6/7] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 731610c701..122c63c415 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -603,7 +603,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index f0c962db75..fc642f87d2 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index ff7ffed6e4..5df338f60d 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 2bcb70391a15b605c090f585668161079aa2b0b5 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v5 1/7] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c | 28 ++++++-----
 3 files changed, 91 insertions(+), 31 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index dc1d41dd8d..ad990f5f8d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -207,6 +207,7 @@ static void dumpSequence(Archive *fout, TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, ConstraintInfo *coninfo);
@@ -7036,6 +7037,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7415,6 +7421,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10221,6 +10248,9 @@ dumpDumpableObject(Archive *fout, DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16408,6 +16438,41 @@ getAttrName(int attrnum, TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16462,16 +16527,6 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -16790,16 +16845,6 @@ dumpConstraint(Archive *fout, ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18304,6 +18349,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 317bb83970..aa51efbe2c 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -53,6 +53,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -377,6 +378,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 654e2ec514..5f0206bbf4 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -57,11 +57,12 @@ static const int dbObjectTypePriority[] =
 	20,							/* DO_ATTRDEF */
 	28,							/* DO_INDEX */
 	29,							/* DO_INDEX_ATTACH */
-	30,							/* DO_STATSEXT */
-	31,							/* DO_RULE */
-	32,							/* DO_TRIGGER */
+	30,							/* DO_INDEX_CLUSTER_ON */
+	31,							/* DO_STATSEXT */
+	32,							/* DO_RULE */
+	33,							/* DO_TRIGGER */
 	27,							/* DO_CONSTRAINT */
-	33,							/* DO_FK_CONSTRAINT */
+	34,							/* DO_FK_CONSTRAINT */
 	2,							/* DO_PROCLANG */
 	10,							/* DO_CAST */
 	23,							/* DO_TABLE_DATA */
@@ -73,18 +74,18 @@ static const int dbObjectTypePriority[] =
 	15,							/* DO_TSCONFIG */
 	16,							/* DO_FDW */
 	17,							/* DO_FOREIGN_SERVER */
-	38,							/* DO_DEFAULT_ACL --- done in ACL pass */
+	39,							/* DO_DEFAULT_ACL --- done in ACL pass */
 	3,							/* DO_TRANSFORM */
 	21,							/* DO_BLOB */
 	25,							/* DO_BLOB_DATA */
 	22,							/* DO_PRE_DATA_BOUNDARY */
 	26,							/* DO_POST_DATA_BOUNDARY */
-	39,							/* DO_EVENT_TRIGGER --- next to last! */
-	40,							/* DO_REFRESH_MATVIEW --- last! */
-	34,							/* DO_POLICY */
-	35,							/* DO_PUBLICATION */
-	36,							/* DO_PUBLICATION_REL */
-	37							/* DO_SUBSCRIPTION */
+	40,							/* DO_EVENT_TRIGGER --- next to last! */
+	41,							/* DO_REFRESH_MATVIEW --- last! */
+	35,							/* DO_POLICY */
+	36,							/* DO_PUBLICATION */
+	37,							/* DO_PUBLICATION_REL */
+	38							/* DO_SUBSCRIPTION */
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1292,6 +1293,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From cb817c479d2a2d4ae94cfa8d215e369b5d206738 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v6 1/7] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c |  8 ++++
 3 files changed, 82 insertions(+), 20 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 798d14580e..e6526392e5 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -208,6 +208,7 @@ static void dumpSequence(Archive *fout, TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, ConstraintInfo *coninfo);
@@ -7092,6 +7093,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7471,6 +7477,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10296,6 +10323,9 @@ dumpDumpableObject(Archive *fout, DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16516,6 +16546,41 @@ getAttrName(int attrnum, TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16570,16 +16635,6 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -16906,16 +16961,6 @@ dumpConstraint(Archive *fout, ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18421,6 +18466,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 1290f9659b..57def4c009 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -54,6 +54,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -386,6 +387,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 46461fb6a1..dd5b233196 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -75,6 +75,7 @@ enum dbObjectTypePriorities
 	PRIO_CONSTRAINT,
 	PRIO_INDEX,
 	PRIO_INDEX_ATTACH,
+	PRIO_INDEX_CLUSTER_ON,
 	PRIO_STATSEXT,
 	PRIO_RULE,
 	PRIO_TRIGGER,
@@ -108,6 +109,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_ATTRDEF,				/* DO_ATTRDEF */
 	PRIO_INDEX,					/* DO_INDEX */
 	PRIO_INDEX_ATTACH,			/* DO_INDEX_ATTACH */
+	PRIO_INDEX_CLUSTER_ON,			/* DO_INDEX_CLUSTER_ON */
 	PRIO_STATSEXT,				/* DO_STATSEXT */
 	PRIO_RULE,					/* DO_RULE */
 	PRIO_TRIGGER,				/* DO_TRIGGER */
@@ -136,6 +138,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_PUBLICATION,			/* DO_PUBLICATION */
 	PRIO_PUBLICATION_REL,		/* DO_PUBLICATION_REL */
 	PRIO_SUBSCRIPTION			/* DO_SUBSCRIPTION */
+
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1348,6 +1351,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From f5b22edbfbf80e057a5795ab00e92ce41ad6168c Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v6 2/7] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 172 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 208 insertions(+), 54 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 5dd21a0189..fb5deddb35 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -192,6 +192,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..838bcd9e72 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -135,7 +140,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -146,14 +151,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -191,8 +188,32 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +223,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +245,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -352,9 +351,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -398,8 +398,13 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -415,6 +420,14 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -483,6 +496,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -507,12 +523,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -584,10 +594,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1582,3 +1588,77 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 6abcbea963..3a6a4831e1 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..c30ca01726 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..e4448350e7 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+   relname   | relkind | ?column? 
+-------------+---------+----------
+ clstrpart   | p       | t
+ clstrpart1  | p       | t
+ clstrpart11 | r       | f
+ clstrpart12 | p       | t
+ clstrpart2  | r       | f
+ clstrpart3  | p       | t
+ clstrpart33 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+    indexrelid     | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..22225dc924 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY 1;
+-- Check that clustering sets new indisclustered:
+SELECT i.indexrelid::regclass::text, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY 1;
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From d99d6b22da07f1c575403411ee8d042e8bae34f9 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v6 3/7] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 109 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 125 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 838bcd9e72..078b97fbb9 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -74,6 +74,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -510,66 +511,88 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel), ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index f9f3ff3b62..0a65698c28 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e4448350e7..a9fb9f1021 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 22225dc924..d15bd51496 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 690be02168bce28b8f110946d4f04f449639f2a2 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v6 4/7] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 078b97fbb9..cdb49985ce 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -594,6 +594,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index a9fb9f1021..6d88978387 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index d15bd51496..c9bb204a93 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 811dbf5135da57cd0ee14f213f566b092a264c3a Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v6 5/7] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 0a65698c28..ffc809822b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4006,6 +4006,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6d88978387..f0c962db75 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index c9bb204a93..ff7ffed6e4 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 50edd08cf9893e2d29c849825b812a6706d4bc61 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v6 6/7] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index b8cd35e995..e15fb42c9c 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -603,7 +603,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index f0c962db75..fc642f87d2 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index ff7ffed6e4..5df338f60d 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From b55a919ef90e82f5233b2a8f789c129b264615cb Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 Nov 2020 17:34:07 -0600
Subject: [PATCH v6 7/7] pg_dump: partitioned index depend on its partitions

This is required for restoring clustered parent index, which is marked INVALID
until indexes have been built on all its child tables, and it's prohibited to
CLUSTER ON an INVALID index

See also: 8cff4f5348d075e063100071013f00a900c32b0f
---
 src/backend/commands/tablecmds.c | 6 +++---
 src/bin/pg_dump/common.c         | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 8687e9a97c..865ab6c2e9 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -17493,6 +17493,9 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		table_close(idxRel, RowExclusiveLock);
 	}
 
+	/* make sure we see the validation we just did */
+	CommandCounterIncrement();
+
 	/*
 	 * If this index is in turn a partition of a larger index, validating it
 	 * might cause the parent to become valid also.  Try that.
@@ -17504,9 +17507,6 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		Relation	parentIdx,
 					parentTbl;
 
-		/* make sure we see the validation we just did */
-		CommandCounterIncrement();
-
 		parentIdxId = get_partition_parent(RelationGetRelid(partedIdx));
 		parentTblId = get_partition_parent(RelationGetRelid(partedTbl));
 		parentIdx = relation_open(parentIdxId, AccessExclusiveLock);
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index b0f02bc1f6..2a7d9b463c 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -429,6 +429,12 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			attachinfo[k].parentIdx = parentidx;
 			attachinfo[k].partitionIdx = index;
 
+			/*
+			 * We want dependencies from parent to partition (so that the
+			 * partition index is created first)
+			 */
+			addObjectDependency(&parentidx->dobj, index->dobj.dumpId);
+
 			/*
 			 * We must state the DO_INDEX_ATTACH object's dependencies
 			 * explicitly, since it will not match anything in pg_depend.
@@ -446,6 +452,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			 */
 			addObjectDependency(&attachinfo[k].dobj, index->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj, parentidx->dobj.dumpId);
+			// addObjectDependency(&parentidx->dobj, attachinfo[k].dobj.dumpId);
+
 			addObjectDependency(&attachinfo[k].dobj,
 								index->indextable->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj,
-- 
2.17.0

From 1101d6b8a44f5cc170816f305476750352dc06de Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v7 1/7] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c |  8 ++++
 3 files changed, 82 insertions(+), 20 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index d99b61e621..8dc8a42964 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -208,6 +208,7 @@ static void dumpSequence(Archive *fout, TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, ConstraintInfo *coninfo);
@@ -7092,6 +7093,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7471,6 +7477,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10323,6 +10350,9 @@ dumpDumpableObject(Archive *fout, DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16543,6 +16573,41 @@ getAttrName(int attrnum, TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16597,16 +16662,6 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -16933,16 +16988,6 @@ dumpConstraint(Archive *fout, ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18448,6 +18493,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 1290f9659b..57def4c009 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -54,6 +54,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -386,6 +387,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 46461fb6a1..dd5b233196 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -75,6 +75,7 @@ enum dbObjectTypePriorities
 	PRIO_CONSTRAINT,
 	PRIO_INDEX,
 	PRIO_INDEX_ATTACH,
+	PRIO_INDEX_CLUSTER_ON,
 	PRIO_STATSEXT,
 	PRIO_RULE,
 	PRIO_TRIGGER,
@@ -108,6 +109,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_ATTRDEF,				/* DO_ATTRDEF */
 	PRIO_INDEX,					/* DO_INDEX */
 	PRIO_INDEX_ATTACH,			/* DO_INDEX_ATTACH */
+	PRIO_INDEX_CLUSTER_ON,			/* DO_INDEX_CLUSTER_ON */
 	PRIO_STATSEXT,				/* DO_STATSEXT */
 	PRIO_RULE,					/* DO_RULE */
 	PRIO_TRIGGER,				/* DO_TRIGGER */
@@ -136,6 +138,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_PUBLICATION,			/* DO_PUBLICATION */
 	PRIO_PUBLICATION_REL,		/* DO_PUBLICATION_REL */
 	PRIO_SUBSCRIPTION			/* DO_SUBSCRIPTION */
+
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1348,6 +1351,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From 0004939e44906d7b32f5f6239109cc25ac72e301 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v7 2/7] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 174 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 209 insertions(+), 55 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 5dd21a0189..fb5deddb35 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -192,6 +192,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..9b6673867c 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -135,7 +140,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -146,14 +151,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -189,10 +186,34 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		}
 
 		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		table_close(rel, ShareUpdateExclusiveLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +223,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +245,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -352,9 +351,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -398,8 +398,13 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -415,6 +420,14 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -483,6 +496,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -507,12 +523,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -584,10 +594,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1582,3 +1588,77 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index a75647b1cc..781aa95abc 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..c30ca01726 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..c74cfa88cc 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+      relname      | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..9bcc77695c 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 4995e70a192989ecda4d1b3798c0d00ba47f06c4 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v7 3/7] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 109 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 125 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 9b6673867c..78c2c2ba72 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -74,6 +74,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -510,66 +511,88 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel), ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 127ba7835d..4ca1ffbfa4 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index c74cfa88cc..1d436dfaae 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 9bcc77695c..0ded2be1ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From c8afb42bc44ab8cc6349bd53614bb6da72da7afa Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v7 4/7] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 78c2c2ba72..05c84e5582 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -594,6 +594,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 1d436dfaae..6cba3cc4f9 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 0ded2be1ca..a1d132f288 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From e92499f78950405b1b8f92c6240909335bdebc17 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v7 5/7] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 4ca1ffbfa4..cc57c149ed 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4117,6 +4117,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6cba3cc4f9..e7f0889743 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index a1d132f288..3c8085c69e 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From e91b525beafbc93223807c68d557b95f7dce3e94 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v7 6/7] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 1cb9172a5f..3611da45e6 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -604,7 +604,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e7f0889743..a3943c13f5 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 3c8085c69e..22628e90ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 9ac8ebd70cc50132f16272df3eae7878b69d6082 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 Nov 2020 17:34:07 -0600
Subject: [PATCH v7 7/7] pg_dump: partitioned index depend on its partitions

This is required for restoring clustered parent index, which is marked INVALID
until indexes have been built on all its child tables, and it's prohibited to
CLUSTER ON an INVALID index

See also: 8cff4f5348d075e063100071013f00a900c32b0f
---
 src/backend/commands/tablecmds.c | 6 +++---
 src/bin/pg_dump/common.c         | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 420991e315..a478c13990 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -17521,6 +17521,9 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		table_close(idxRel, RowExclusiveLock);
 	}
 
+	/* make sure we see the validation we just did */
+	CommandCounterIncrement();
+
 	/*
 	 * If this index is in turn a partition of a larger index, validating it
 	 * might cause the parent to become valid also.  Try that.
@@ -17532,9 +17535,6 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		Relation	parentIdx,
 					parentTbl;
 
-		/* make sure we see the validation we just did */
-		CommandCounterIncrement();
-
 		parentIdxId = get_partition_parent(RelationGetRelid(partedIdx));
 		parentTblId = get_partition_parent(RelationGetRelid(partedTbl));
 		parentIdx = relation_open(parentIdxId, AccessExclusiveLock);
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 1a261a5545..cdfba058fc 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -429,6 +429,12 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			attachinfo[k].parentIdx = parentidx;
 			attachinfo[k].partitionIdx = index;
 
+			/*
+			 * We want dependencies from parent to partition (so that the
+			 * partition index is created first)
+			 */
+			addObjectDependency(&parentidx->dobj, index->dobj.dumpId);
+
 			/*
 			 * We must state the DO_INDEX_ATTACH object's dependencies
 			 * explicitly, since it will not match anything in pg_depend.
@@ -446,6 +452,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			 */
 			addObjectDependency(&attachinfo[k].dobj, index->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj, parentidx->dobj.dumpId);
+			// addObjectDependency(&parentidx->dobj, attachinfo[k].dobj.dumpId);
+
 			addObjectDependency(&attachinfo[k].dobj,
 								index->indextable->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj,
-- 
2.17.0

From 1614cfa411dabd74faa64dc805f52405e2572239 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v8 1/8] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c |  8 ++++
 3 files changed, 82 insertions(+), 20 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index eb988d7eb4..e93d2eb828 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -208,6 +208,7 @@ static void dumpSequence(Archive *fout, const TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, const TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, const IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, const IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, const StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, const ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, const ConstraintInfo *coninfo);
@@ -7092,6 +7093,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7471,6 +7477,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10323,6 +10350,9 @@ dumpDumpableObject(Archive *fout, const DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (const SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16543,6 +16573,41 @@ getAttrName(int attrnum, const TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16597,16 +16662,6 @@ dumpIndex(Archive *fout, const IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -16933,16 +16988,6 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18448,6 +18493,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 0a2213fb06..627c8fbdab 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -54,6 +54,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -386,6 +387,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 46461fb6a1..dd5b233196 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -75,6 +75,7 @@ enum dbObjectTypePriorities
 	PRIO_CONSTRAINT,
 	PRIO_INDEX,
 	PRIO_INDEX_ATTACH,
+	PRIO_INDEX_CLUSTER_ON,
 	PRIO_STATSEXT,
 	PRIO_RULE,
 	PRIO_TRIGGER,
@@ -108,6 +109,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_ATTRDEF,				/* DO_ATTRDEF */
 	PRIO_INDEX,					/* DO_INDEX */
 	PRIO_INDEX_ATTACH,			/* DO_INDEX_ATTACH */
+	PRIO_INDEX_CLUSTER_ON,			/* DO_INDEX_CLUSTER_ON */
 	PRIO_STATSEXT,				/* DO_STATSEXT */
 	PRIO_RULE,					/* DO_RULE */
 	PRIO_TRIGGER,				/* DO_TRIGGER */
@@ -136,6 +138,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_PUBLICATION,			/* DO_PUBLICATION */
 	PRIO_PUBLICATION_REL,		/* DO_PUBLICATION_REL */
 	PRIO_SUBSCRIPTION			/* DO_SUBSCRIPTION */
+
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1348,6 +1351,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From 15c082c0b3b987386eaab8785403ef5ca9c09fba Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v8 2/8] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 174 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 209 insertions(+), 55 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 5dd21a0189..fb5deddb35 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -192,6 +192,12 @@ CLUSTER [VERBOSE]
     are periodically reclustered.
    </para>
 
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    index partition of the given partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..9b6673867c 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -135,7 +140,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -146,14 +151,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -189,10 +186,34 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		}
 
 		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		table_close(rel, ShareUpdateExclusiveLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +223,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +245,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -352,9 +351,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -398,8 +398,13 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -415,6 +420,14 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -483,6 +496,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -507,12 +523,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -584,10 +594,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1582,3 +1588,77 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels are also processed by cluster_rel, to
+		 * call check_index_is_clusterable() and mark_index_clustered().
+		 */
+
+		/*
+		 * We have to build the list in a different memory context so it will
+		 * survive the cross-transaction processing
+		 */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+
+		MemoryContextSwitchTo(old_context);
+	}
+
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ba301a6b08 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..c30ca01726 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..c74cfa88cc 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+      relname      | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..9bcc77695c 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 2b0b1d79ba0e0f54b348d77a1650d674b8dd8de6 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Mon, 8 Feb 2021 20:45:26 -0600
Subject: [PATCH v8 3/8] f! progress reporting..

This follows the precedent of pg_stat_progress_create_index, which
simultaneously shows the progress of 1) the leaf partition, and 2) the overall
progress as partitions_done / partitions_total.

This also includes current_child_index_relid, but the create_index view
doesn't, so maybe this shouldn't, either.
---
 src/backend/catalog/system_views.sql |  4 +-
 src/backend/commands/cluster.c       | 64 +++++++++++++++++-----------
 src/include/commands/progress.h      |  3 ++
 src/test/regress/expected/rules.out  |  4 +-
 4 files changed, 47 insertions(+), 28 deletions(-)

diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index fa58afd9d7..9a3cb5f935 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1069,7 +1069,9 @@ CREATE VIEW pg_stat_progress_cluster AS
         S.param5 AS heap_tuples_written,
         S.param6 AS heap_blks_total,
         S.param7 AS heap_blks_scanned,
-        S.param8 AS index_rebuild_count
+        S.param8 AS index_rebuild_count,
+        S.param18 AS partitions_total,
+        S.param19 AS partitions_done
     FROM pg_stat_get_progress_info('CLUSTER') AS S
         LEFT JOIN pg_database D ON S.datid = D.oid;
 
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 9b6673867c..cb4fc350c6 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -77,7 +77,7 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
-static void cluster_multiple_rels(List *rvs, int options);
+static void cluster_multiple_rels(List *rvs, int options, bool ispartitioned);
 
 
 /*---------------------------------------------------------------------------
@@ -188,16 +188,28 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, ShareUpdateExclusiveLock);
 
+		pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
 		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
 		{
+			pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+					OidIsValid(indexOid) ? PROGRESS_CLUSTER_COMMAND_CLUSTER :
+					PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
+
 			/* Do the job. */
 			cluster_rel(tableOid, indexOid, &params);
+			pgstat_progress_end_command();
 		}
 		else
 		{
 			List	   *rvs;
 			MemoryContext cluster_context;
 
+			int64		progress_val[2];
+			const int	progress_index[] = {
+				PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_PARTITIONS_TOTAL,
+			};
+
 			/* Refuse to hold strong locks in a user transaction */
 			PreventInTransactionBlock(isTopLevel, "CLUSTER");
 
@@ -206,7 +218,20 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 												ALLOCSET_DEFAULT_SIZES);
 
 			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
-			cluster_multiple_rels(rvs, params.options);
+
+			/* Report vacuum full or cluster and number of partitions */
+			progress_val[0] = OidIsValid(indexOid) ?
+				PROGRESS_CLUSTER_COMMAND_CLUSTER :
+				PROGRESS_CLUSTER_COMMAND_VACUUM_FULL;
+			progress_val[1] = list_length(rvs);
+// This is currently showing the total number of *tables*, including the
+// parent, and intermediate partitions, so the column should be renamed, or
+// we should count the number of leaf partitions
+
+			pgstat_progress_update_multi_param(2, progress_index, progress_val);
+
+			cluster_multiple_rels(rvs, params.options, true);
+			pgstat_progress_end_command();
 
 			/* Start a new transaction for the cleanup work. */
 			StartTransactionCommand();
@@ -245,7 +270,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED, false);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -282,14 +307,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	/* Check for user-requested abort. */
 	CHECK_FOR_INTERRUPTS();
 
-	pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
-	if (OidIsValid(indexOid))
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_CLUSTER);
-	else
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
-
 	/*
 	 * We grab exclusive access to the target rel and index for the duration
 	 * of the transaction.  (This is redundant for the single-transaction
@@ -300,10 +317,7 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* If the table has gone away, we can skip processing it */
 	if (!OldHeap)
-	{
-		pgstat_progress_end_command();
 		return;
-	}
 
 	/*
 	 * Since we may open a new transaction for each relation, we have to check
@@ -319,7 +333,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (!pg_class_ownercheck(tableOid, GetUserId()))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -334,7 +347,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -346,7 +358,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid)))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 
@@ -357,7 +368,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 		}
@@ -416,7 +426,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		!RelationIsPopulated(OldHeap))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -424,7 +433,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -440,8 +448,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	rebuild_relation(OldHeap, indexOid, verbose);
 
 	/* NB: rebuild_relation does table_close() on OldHeap */
-
-	pgstat_progress_end_command();
 }
 
 /*
@@ -1366,7 +1372,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	ReindexParams reindex_params = {0};
 	int			i;
 
-	/* Report that we are now swapping relation files */
+	/* Report that we are now swapping relation files XXX */
 	pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
 								 PROGRESS_CLUSTER_PHASE_SWAP_REL_FILES);
 
@@ -1417,13 +1423,13 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	else if (newrelpersistence == RELPERSISTENCE_PERMANENT)
 		reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT;
 
-	/* Report that we are now reindexing relations */
+	/* Report that we are now reindexing relations XXX */
 	pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
 								 PROGRESS_CLUSTER_PHASE_REBUILD_INDEX);
 
 	reindex_relation(OIDOldHeap, reindex_flags, &reindex_params);
 
-	/* Report that we are now doing clean up */
+	/* Report that we are now doing clean up XXX */
 	pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
 								 PROGRESS_CLUSTER_PHASE_FINAL_CLEANUP);
 
@@ -1633,9 +1639,10 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
 
 /* Cluster each relation in a separate transaction */
 static void
-cluster_multiple_rels(List *rvs, int options)
+cluster_multiple_rels(List *rvs, int options, bool ispartitioned)
 {
 	ListCell *lc;
+	off_t	  childnum = 0;
 
 	/* Commit to get out of starting transaction */
 	PopActiveSnapshot();
@@ -1658,6 +1665,11 @@ cluster_multiple_rels(List *rvs, int options)
 		cluster_rel(rvtc->tableOid, rvtc->indexOid,
 					&cluster_params);
 
+		if (ispartitioned)
+			pgstat_progress_update_param(PROGRESS_CLUSTER_PARTITIONS_DONE,
+					childnum++);
+
+
 		PopActiveSnapshot();
 		CommitTransactionCommand();
 	}
diff --git a/src/include/commands/progress.h b/src/include/commands/progress.h
index 95ec5d02e9..13499a3e72 100644
--- a/src/include/commands/progress.h
+++ b/src/include/commands/progress.h
@@ -60,6 +60,9 @@
 #define PROGRESS_CLUSTER_TOTAL_HEAP_BLKS		5
 #define PROGRESS_CLUSTER_HEAP_BLKS_SCANNED		6
 #define PROGRESS_CLUSTER_INDEX_REBUILD_COUNT	7
+/* Need to avoid the CREATE INDEX params */
+#define PROGRESS_CLUSTER_PARTITIONS_TOTAL	17
+#define PROGRESS_CLUSTER_PARTITIONS_DONE	18
 
 /* Phases of cluster (as advertised via PROGRESS_CLUSTER_PHASE) */
 #define PROGRESS_CLUSTER_PHASE_SEQ_SCAN_HEAP	1
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index b632d9f2ea..d1fea532bc 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1941,7 +1941,9 @@ pg_stat_progress_cluster| SELECT s.pid,
     s.param5 AS heap_tuples_written,
     s.param6 AS heap_blks_total,
     s.param7 AS heap_blks_scanned,
-    s.param8 AS index_rebuild_count
+    s.param8 AS index_rebuild_count,
+    s.param18 AS partitions_total,
+    s.param19 AS partitions_done
    FROM (pg_stat_get_progress_info('CLUSTER'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20)
      LEFT JOIN pg_database d ON ((s.datid = d.oid)));
 pg_stat_progress_copy| SELECT s.pid,
-- 
2.17.0

From 8cfd38f0f4752149a4ee7d40ec5866941968b17f Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v8 4/8] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 109 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 125 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index cb4fc350c6..5c08f0642e 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -74,6 +74,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -516,66 +517,88 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel), ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 127ba7835d..4ca1ffbfa4 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index c74cfa88cc..1d436dfaae 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 9bcc77695c..0ded2be1ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From f72ffaf24db124cd3b16cc2c9b689ed8729ec72c Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v8 5/8] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 5c08f0642e..60272bc010 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -600,6 +600,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 1d436dfaae..6cba3cc4f9 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 0ded2be1ca..a1d132f288 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From b796243672e8a201ffe1e72d2f44c8bb78947900 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v8 6/8] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 4ca1ffbfa4..cc57c149ed 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4117,6 +4117,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6cba3cc4f9..e7f0889743 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index a1d132f288..3c8085c69e 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 4cd8925f74864daea41dc29672b712a04f25eb59 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v8 7/8] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  2 +-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 1514937748..08fdf02ebc 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -604,7 +604,7 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) && get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e7f0889743..a3943c13f5 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 3c8085c69e..22628e90ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From c30b5e94555c3193299210ed9f102c4633682d54 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 Nov 2020 17:34:07 -0600
Subject: [PATCH v8 8/8] pg_dump: partitioned index depend on its partitions

This is required for restoring clustered parent index, which is marked INVALID
until indexes have been built on all its child tables, and it's prohibited to
CLUSTER ON an INVALID index

See also: 8cff4f5348d075e063100071013f00a900c32b0f
---
 src/backend/commands/tablecmds.c | 6 +++---
 src/bin/pg_dump/common.c         | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 420991e315..a478c13990 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -17521,6 +17521,9 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		table_close(idxRel, RowExclusiveLock);
 	}
 
+	/* make sure we see the validation we just did */
+	CommandCounterIncrement();
+
 	/*
 	 * If this index is in turn a partition of a larger index, validating it
 	 * might cause the parent to become valid also.  Try that.
@@ -17532,9 +17535,6 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		Relation	parentIdx,
 					parentTbl;
 
-		/* make sure we see the validation we just did */
-		CommandCounterIncrement();
-
 		parentIdxId = get_partition_parent(RelationGetRelid(partedIdx));
 		parentTblId = get_partition_parent(RelationGetRelid(partedTbl));
 		parentIdx = relation_open(parentIdxId, AccessExclusiveLock);
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 1a261a5545..cdfba058fc 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -429,6 +429,12 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			attachinfo[k].parentIdx = parentidx;
 			attachinfo[k].partitionIdx = index;
 
+			/*
+			 * We want dependencies from parent to partition (so that the
+			 * partition index is created first)
+			 */
+			addObjectDependency(&parentidx->dobj, index->dobj.dumpId);
+
 			/*
 			 * We must state the DO_INDEX_ATTACH object's dependencies
 			 * explicitly, since it will not match anything in pg_depend.
@@ -446,6 +452,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			 */
 			addObjectDependency(&attachinfo[k].dobj, index->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj, parentidx->dobj.dumpId);
+			// addObjectDependency(&parentidx->dobj, attachinfo[k].dobj.dumpId);
+
 			addObjectDependency(&attachinfo[k].dobj,
 								index->indextable->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj,
-- 
2.17.0

From 3a39edbed1595efc230aac1de09fc276cc7ca7f4 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v9 1/8] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c |  8 ++++
 3 files changed, 82 insertions(+), 20 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index eb988d7eb4..e93d2eb828 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -208,6 +208,7 @@ static void dumpSequence(Archive *fout, const TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, const TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, const IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, const IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, const StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, const ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, const ConstraintInfo *coninfo);
@@ -7092,6 +7093,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7471,6 +7477,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10323,6 +10350,9 @@ dumpDumpableObject(Archive *fout, const DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (const SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16543,6 +16573,41 @@ getAttrName(int attrnum, const TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16597,16 +16662,6 @@ dumpIndex(Archive *fout, const IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -16933,16 +16988,6 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18448,6 +18493,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 0a2213fb06..627c8fbdab 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -54,6 +54,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -386,6 +387,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 46461fb6a1..dd5b233196 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -75,6 +75,7 @@ enum dbObjectTypePriorities
 	PRIO_CONSTRAINT,
 	PRIO_INDEX,
 	PRIO_INDEX_ATTACH,
+	PRIO_INDEX_CLUSTER_ON,
 	PRIO_STATSEXT,
 	PRIO_RULE,
 	PRIO_TRIGGER,
@@ -108,6 +109,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_ATTRDEF,				/* DO_ATTRDEF */
 	PRIO_INDEX,					/* DO_INDEX */
 	PRIO_INDEX_ATTACH,			/* DO_INDEX_ATTACH */
+	PRIO_INDEX_CLUSTER_ON,			/* DO_INDEX_CLUSTER_ON */
 	PRIO_STATSEXT,				/* DO_STATSEXT */
 	PRIO_RULE,					/* DO_RULE */
 	PRIO_TRIGGER,				/* DO_TRIGGER */
@@ -136,6 +138,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_PUBLICATION,			/* DO_PUBLICATION */
 	PRIO_PUBLICATION_REL,		/* DO_PUBLICATION_REL */
 	PRIO_SUBSCRIPTION			/* DO_SUBSCRIPTION */
+
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1348,6 +1351,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From 0933879bdd1d21fdb8d31a3340f3815c45dfc7b4 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v9 2/8] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.

VACUUM (including vacuum full) has recursed into partition hierarchies since
partitions were introduced in v10 (3c3bb9933).
---
 doc/src/sgml/ref/cluster.sgml         |   7 ++
 src/backend/commands/cluster.c        | 173 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 209 insertions(+), 55 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 0d9720fd8e..17509b35eb 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -197,6 +197,13 @@ CLUSTER [VERBOSE]
     in the <structname>pg_stat_progress_cluster</structname> view. See
     <xref linkend="cluster-progress-reporting"/> for details.
   </para>
+
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    partition of the specified partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..0c08ac56dc 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -135,7 +140,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -146,14 +151,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -189,10 +186,34 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		}
 
 		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		table_close(rel, ShareUpdateExclusiveLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +223,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +245,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -352,9 +351,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -398,8 +398,13 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -415,6 +420,14 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -483,6 +496,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -507,12 +523,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -584,10 +594,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1582,3 +1588,76 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	/*
+	 * We have to build the list in a different memory context so it will
+	 * survive the cross-transaction processing
+	 */
+	old_context = MemoryContextSwitchTo(cluster_context);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels (including the top indexOid) are included,
+		 * so as to be processed by cluster_rel, which calls
+		 * check_index_is_clusterable() and mark_index_clustered().
+		 */
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+	}
+
+	MemoryContextSwitchTo(old_context);
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9f0208ac49..53d585c4d3 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..c30ca01726 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index bdae8fe00c..c74cfa88cc 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -439,14 +439,62 @@ select * from clstr_temp;
 
 drop table clstr_temp;
 RESET SESSION AUTHORIZATION;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+      relname      | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 188183647c..9bcc77695c 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -196,12 +196,30 @@ drop table clstr_temp;
 
 RESET SESSION AUTHORIZATION;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 7001773daa339a49cb7b2e32c398fdd1a8e299b8 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Mon, 8 Feb 2021 20:45:26 -0600
Subject: [PATCH v9 3/8] f! progress reporting..

This follows the precedent of pg_stat_progress_create_index, which
simultaneously shows the progress of 1) the leaf partition, and 2) the overall
progress as partitions_done / partitions_total.

This also includes current_child_index_relid, but the create_index view
doesn't, so maybe this shouldn't, either.
---
 doc/src/sgml/monitoring.sgml         | 21 +++++++++++
 src/backend/catalog/system_views.sql |  4 +-
 src/backend/commands/cluster.c       | 55 ++++++++++++++++------------
 src/backend/commands/vacuum.c        |  5 +++
 src/include/commands/progress.h      |  3 ++
 src/test/regress/expected/rules.out  |  4 +-
 6 files changed, 67 insertions(+), 25 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 3513e127b7..dca47f6a48 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -6231,6 +6231,27 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
        is <literal>rebuilding index</literal>.
       </para></entry>
      </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>total_partitions</structfield> <type>bigint</type>
+      </para>
+       When clustering a partitioned table, this column is set to the total
+       number of partitions to be clustered.
+      <para>
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>done_partitions</structfield> <type>bigint</type>
+      </para>
+      <para>
+       When clustering a partitioned table, this column is set to the number
+       of partitions which have been clustered.
+      </para></entry>
+     </row>
+
     </tbody>
    </tgroup>
   </table>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index fc94a73a54..21c27f0437 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1070,7 +1070,9 @@ CREATE VIEW pg_stat_progress_cluster AS
         S.param5 AS heap_tuples_written,
         S.param6 AS heap_blks_total,
         S.param7 AS heap_blks_scanned,
-        S.param8 AS index_rebuild_count
+        S.param8 AS index_rebuild_count,
+        S.param18 AS partitions_total,
+        S.param19 AS partitions_done
     FROM pg_stat_get_progress_info('CLUSTER') AS S
         LEFT JOIN pg_database D ON S.datid = D.oid;
 
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 0c08ac56dc..7d8d1d8a69 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -77,7 +77,7 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
-static void cluster_multiple_rels(List *rvs, int options);
+static void cluster_multiple_rels(List *rvs, int options, bool ispartitioned);
 
 
 /*---------------------------------------------------------------------------
@@ -188,16 +188,26 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, ShareUpdateExclusiveLock);
 
+		pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
 		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
 		{
 			/* Do the job. */
+			pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+					PROGRESS_CLUSTER_COMMAND_CLUSTER);
 			cluster_rel(tableOid, indexOid, &params);
+			pgstat_progress_end_command();
 		}
 		else
 		{
 			List	   *rvs;
 			MemoryContext cluster_context;
 
+			int64		progress_val[2];
+			const int	progress_index[2] = {
+				PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_PARTITIONS_TOTAL,
+			};
+
 			/* Refuse to hold strong locks in a user transaction */
 			PreventInTransactionBlock(isTopLevel, "CLUSTER");
 
@@ -206,7 +216,15 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 												ALLOCSET_DEFAULT_SIZES);
 
 			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
-			cluster_multiple_rels(rvs, params.options);
+
+			/* Report command and number of partitions */
+			progress_val[0] = PROGRESS_CLUSTER_COMMAND_CLUSTER;
+			/* XXX: rvs includes the parent, which is not a "partition" */
+			progress_val[1] = list_length(rvs);
+
+			pgstat_progress_update_multi_param(2, progress_index, progress_val);
+			cluster_multiple_rels(rvs, params.options, true);
+			pgstat_progress_end_command();
 
 			/* Start a new transaction for the cleanup work. */
 			StartTransactionCommand();
@@ -245,7 +263,11 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
+
+		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_COMMAND_CLUSTER);
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED, false);
+		pgstat_progress_end_command();
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -282,14 +304,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	/* Check for user-requested abort. */
 	CHECK_FOR_INTERRUPTS();
 
-	pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
-	if (OidIsValid(indexOid))
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_CLUSTER);
-	else
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
-
 	/*
 	 * We grab exclusive access to the target rel and index for the duration
 	 * of the transaction.  (This is redundant for the single-transaction
@@ -300,10 +314,7 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* If the table has gone away, we can skip processing it */
 	if (!OldHeap)
-	{
-		pgstat_progress_end_command();
 		return;
-	}
 
 	/*
 	 * Since we may open a new transaction for each relation, we have to check
@@ -319,7 +330,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (!pg_class_ownercheck(tableOid, GetUserId()))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -334,7 +344,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -346,7 +355,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid)))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 
@@ -357,7 +365,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 		}
@@ -416,7 +423,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		!RelationIsPopulated(OldHeap))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -424,7 +430,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -440,8 +445,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	rebuild_relation(OldHeap, indexOid, verbose);
 
 	/* NB: rebuild_relation does table_close() on OldHeap */
-
-	pgstat_progress_end_command();
 }
 
 /*
@@ -1632,9 +1635,10 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
 
 /* Cluster each relation in a separate transaction */
 static void
-cluster_multiple_rels(List *rvs, int options)
+cluster_multiple_rels(List *rvs, int options, bool ispartitioned)
 {
 	ListCell *lc;
+	off_t	  childnum = 0;
 
 	/* Commit to get out of starting transaction */
 	PopActiveSnapshot();
@@ -1657,6 +1661,11 @@ cluster_multiple_rels(List *rvs, int options)
 		cluster_rel(rvtc->tableOid, rvtc->indexOid,
 					&cluster_params);
 
+		if (ispartitioned)
+			pgstat_progress_update_param(PROGRESS_CLUSTER_PARTITIONS_DONE,
+					++childnum);
+
+
 		PopActiveSnapshot();
 		CommitTransactionCommand();
 	}
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index c064352e23..05d52858b1 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -37,6 +37,7 @@
 #include "catalog/pg_namespace.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
+#include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -1937,7 +1938,11 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams *params)
 			cluster_params.options |= CLUOPT_VERBOSE;
 
 		/* VACUUM FULL is now a variant of CLUSTER; see cluster.c */
+		pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, relid);
+		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
 		cluster_rel(relid, InvalidOid, &cluster_params);
+		pgstat_progress_end_command();
 	}
 	else
 		table_relation_vacuum(onerel, params, vac_strategy);
diff --git a/src/include/commands/progress.h b/src/include/commands/progress.h
index 95ec5d02e9..13499a3e72 100644
--- a/src/include/commands/progress.h
+++ b/src/include/commands/progress.h
@@ -60,6 +60,9 @@
 #define PROGRESS_CLUSTER_TOTAL_HEAP_BLKS		5
 #define PROGRESS_CLUSTER_HEAP_BLKS_SCANNED		6
 #define PROGRESS_CLUSTER_INDEX_REBUILD_COUNT	7
+/* Need to avoid the CREATE INDEX params */
+#define PROGRESS_CLUSTER_PARTITIONS_TOTAL	17
+#define PROGRESS_CLUSTER_PARTITIONS_DONE	18
 
 /* Phases of cluster (as advertised via PROGRESS_CLUSTER_PHASE) */
 #define PROGRESS_CLUSTER_PHASE_SEQ_SCAN_HEAP	1
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index b1c9b7bdfe..c888415235 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1943,7 +1943,9 @@ pg_stat_progress_cluster| SELECT s.pid,
     s.param5 AS heap_tuples_written,
     s.param6 AS heap_blks_total,
     s.param7 AS heap_blks_scanned,
-    s.param8 AS index_rebuild_count
+    s.param8 AS index_rebuild_count,
+    s.param18 AS partitions_total,
+    s.param19 AS partitions_done
    FROM (pg_stat_get_progress_info('CLUSTER'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20)
      LEFT JOIN pg_database d ON ((s.datid = d.oid)));
 pg_stat_progress_copy| SELECT s.pid,
-- 
2.17.0

From a1c4aecc9dd08b96c460ddc11c7d839259db83a3 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v9 4/8] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 110 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 126 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 7d8d1d8a69..dd8014c206 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -74,6 +74,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -513,66 +514,89 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel),
+											ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8bc652ecd3..5f8fc2ea16 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index c74cfa88cc..1d436dfaae 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -495,6 +495,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 9bcc77695c..0ded2be1ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -220,6 +220,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 015a61bf17129091c21515aee7e8702fce72c0b3 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v9 5/8] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index dd8014c206..8a2e66bbeb 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -598,6 +598,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 1d436dfaae..6cba3cc4f9 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -541,6 +541,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 0ded2be1ca..a1d132f288 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -231,6 +231,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From aeada0f1098d3de5ffae9ff2b24ff1c982125621 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v9 6/8] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 5f8fc2ea16..4485b01b21 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4126,6 +4126,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 6cba3cc4f9..e7f0889743 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -567,6 +567,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index a1d132f288..3c8085c69e 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -239,6 +239,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From ce4f904b4d68218fd7f2420687de25e9e9157949 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v9 7/8] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  3 ++-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 4ef61b5efd..71649b38ee 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -604,7 +604,8 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) &&
+												get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e7f0889743..a3943c13f5 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -581,6 +581,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 3c8085c69e..22628e90ca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -244,6 +244,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 44aa5170d62a1ec5453f1e02c63c754998fa8738 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 Nov 2020 17:34:07 -0600
Subject: [PATCH v9 8/8] pg_dump: partitioned index depend on its partitions

This is required for restoring clustered parent index, which is marked INVALID
until indexes have been built on all its child tables, and it's prohibited to
CLUSTER ON an INVALID index

See also: 8cff4f5348d075e063100071013f00a900c32b0f
---
 src/backend/commands/tablecmds.c | 6 +++---
 src/bin/pg_dump/common.c         | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 559fa1d2e5..eb56890311 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -17497,6 +17497,9 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		table_close(idxRel, RowExclusiveLock);
 	}
 
+	/* make sure we see the validation we just did */
+	CommandCounterIncrement();
+
 	/*
 	 * If this index is in turn a partition of a larger index, validating it
 	 * might cause the parent to become valid also.  Try that.
@@ -17508,9 +17511,6 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		Relation	parentIdx,
 					parentTbl;
 
-		/* make sure we see the validation we just did */
-		CommandCounterIncrement();
-
 		parentIdxId = get_partition_parent(RelationGetRelid(partedIdx));
 		parentTblId = get_partition_parent(RelationGetRelid(partedTbl));
 		parentIdx = relation_open(parentIdxId, AccessExclusiveLock);
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 1a261a5545..cdfba058fc 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -429,6 +429,12 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			attachinfo[k].parentIdx = parentidx;
 			attachinfo[k].partitionIdx = index;
 
+			/*
+			 * We want dependencies from parent to partition (so that the
+			 * partition index is created first)
+			 */
+			addObjectDependency(&parentidx->dobj, index->dobj.dumpId);
+
 			/*
 			 * We must state the DO_INDEX_ATTACH object's dependencies
 			 * explicitly, since it will not match anything in pg_depend.
@@ -446,6 +452,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			 */
 			addObjectDependency(&attachinfo[k].dobj, index->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj, parentidx->dobj.dumpId);
+			// addObjectDependency(&parentidx->dobj, attachinfo[k].dobj.dumpId);
+
 			addObjectDependency(&attachinfo[k].dobj,
 								index->indextable->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj,
-- 
2.17.0

From 686cd8fc644f1f86d81d7748b66feddd634c4dc8 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 26 Nov 2020 14:37:08 -0600
Subject: [PATCH v10 1/8] pg_dump: make CLUSTER ON a separate dump object..

..since it needs to be restored after any child indexes are restored *and
attached*.  The order needs to be:

1) restore child and parent index (order doesn't matter);
2) attach child index;
3) set cluster on child and parent index (order doesn't matter);
---
 src/bin/pg_dump/pg_dump.c      | 86 ++++++++++++++++++++++++++--------
 src/bin/pg_dump/pg_dump.h      |  8 ++++
 src/bin/pg_dump/pg_dump_sort.c |  8 ++++
 3 files changed, 82 insertions(+), 20 deletions(-)

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 25717ce0e6..9a3044fd8c 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -215,6 +215,7 @@ static void dumpSequence(Archive *fout, const TableInfo *tbinfo);
 static void dumpSequenceData(Archive *fout, const TableDataInfo *tdinfo);
 static void dumpIndex(Archive *fout, const IndxInfo *indxinfo);
 static void dumpIndexAttach(Archive *fout, const IndexAttachInfo *attachinfo);
+static void dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo);
 static void dumpStatisticsExt(Archive *fout, const StatsExtInfo *statsextinfo);
 static void dumpConstraint(Archive *fout, const ConstraintInfo *coninfo);
 static void dumpTableConstraintComment(Archive *fout, const ConstraintInfo *coninfo);
@@ -7232,6 +7233,11 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				i_inddependcollversions;
 	int			ntups;
 
+	int	ncluster = 0;
+	IndexClusterInfo *clusterinfo;
+	clusterinfo = (IndexClusterInfo *)
+		pg_malloc0(numTables * sizeof(IndexClusterInfo));
+
 	for (i = 0; i < numTables; i++)
 	{
 		TableInfo  *tbinfo = &tblinfo[i];
@@ -7611,6 +7617,27 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 				/* Plain secondary index */
 				indxinfo[j].indexconstraint = 0;
 			}
+
+			/* Record each table's CLUSTERed index, if any */
+			if (indxinfo[j].indisclustered)
+			{
+				IndxInfo   *index = &indxinfo[j];
+				IndexClusterInfo *cluster = &clusterinfo[ncluster];
+
+				cluster->dobj.objType = DO_INDEX_CLUSTER_ON;
+				cluster->dobj.catId.tableoid = 0;
+				cluster->dobj.catId.oid = 0;
+				AssignDumpId(&cluster->dobj);
+				cluster->dobj.name = pg_strdup(index->dobj.name);
+				cluster->dobj.namespace = index->indextable->dobj.namespace;
+				cluster->index = index;
+				cluster->indextable = &tblinfo[i];
+
+				/* The CLUSTER ON depends on its index.. */
+				addObjectDependency(&cluster->dobj, index->dobj.dumpId);
+
+				ncluster++;
+			}
 		}
 
 		PQclear(res);
@@ -10472,6 +10499,9 @@ dumpDumpableObject(Archive *fout, const DumpableObject *dobj)
 		case DO_SUBSCRIPTION:
 			dumpSubscription(fout, (const SubscriptionInfo *) dobj);
 			break;
+		case DO_INDEX_CLUSTER_ON:
+			dumpIndexClusterOn(fout, (IndexClusterInfo *) dobj);
+			break;
 		case DO_PRE_DATA_BOUNDARY:
 		case DO_POST_DATA_BOUNDARY:
 			/* never dumped, nothing to do */
@@ -16721,6 +16751,41 @@ getAttrName(int attrnum, const TableInfo *tblInfo)
 	return NULL;				/* keep compiler quiet */
 }
 
+/*
+ * dumpIndexClusterOn
+ *	  record that the index is clustered.
+ */
+static void
+dumpIndexClusterOn(Archive *fout, const IndexClusterInfo *clusterinfo)
+{
+	DumpOptions *dopt = fout->dopt;
+	TableInfo	*tbinfo = clusterinfo->indextable;
+	char		*qindxname;
+	PQExpBuffer	q;
+
+	if (dopt->dataOnly)
+		return;
+
+	q = createPQExpBuffer();
+	qindxname = pg_strdup(fmtId(clusterinfo->dobj.name));
+
+	/* index name is not qualified in this syntax */
+	appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER ON %s;\n",
+					  fmtQualifiedDumpable(tbinfo), qindxname);
+
+	if (clusterinfo->dobj.dump & DUMP_COMPONENT_DEFINITION)
+		ArchiveEntry(fout, clusterinfo->dobj.catId, clusterinfo->dobj.dumpId,
+					 ARCHIVE_OPTS(.tag = clusterinfo->dobj.name,
+								  .namespace = tbinfo->dobj.namespace->dobj.name,
+								  .owner = tbinfo->rolname,
+								  .description = "INDEX CLUSTER ON",
+								  .section = SECTION_POST_DATA,
+								  .createStmt = q->data));
+
+	destroyPQExpBuffer(q);
+	free(qindxname);
+}
+
 /*
  * dumpIndex
  *	  write out to fout a user-defined index
@@ -16775,16 +16840,6 @@ dumpIndex(Archive *fout, const IndxInfo *indxinfo)
 		 * similar code in dumpConstraint!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  qindxname);
-		}
-
 		/*
 		 * If the index has any statistics on some of its columns, generate
 		 * the associated ALTER INDEX queries.
@@ -17111,16 +17166,6 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 		 * similar code in dumpIndex!
 		 */
 
-		/* If the index is clustered, we need to record that. */
-		if (indxinfo->indisclustered)
-		{
-			appendPQExpBuffer(q, "\nALTER TABLE %s CLUSTER",
-							  fmtQualifiedDumpable(tbinfo));
-			/* index name is not qualified in this syntax */
-			appendPQExpBuffer(q, " ON %s;\n",
-							  fmtId(indxinfo->dobj.name));
-		}
-
 		/* If the index defines identity, we need to record that. */
 		if (indxinfo->indisreplident)
 		{
@@ -18626,6 +18671,7 @@ addBoundaryDependencies(DumpableObject **dobjs, int numObjs,
 				break;
 			case DO_INDEX:
 			case DO_INDEX_ATTACH:
+			case DO_INDEX_CLUSTER_ON:
 			case DO_STATSEXT:
 			case DO_REFRESH_MATVIEW:
 			case DO_TRIGGER:
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index 5340843081..af916632db 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -54,6 +54,7 @@ typedef enum
 	DO_ATTRDEF,
 	DO_INDEX,
 	DO_INDEX_ATTACH,
+	DO_INDEX_CLUSTER_ON,
 	DO_STATSEXT,
 	DO_RULE,
 	DO_TRIGGER,
@@ -387,6 +388,13 @@ typedef struct _indxInfo
 	DumpId		indexconstraint;
 } IndxInfo;
 
+typedef struct _indexClusterInfo
+{
+	DumpableObject dobj;
+	TableInfo  *indextable;		/* link to table the index is for */
+	IndxInfo   *index;		/* link to index itself */
+} IndexClusterInfo;
+
 typedef struct _indexAttachInfo
 {
 	DumpableObject dobj;
diff --git a/src/bin/pg_dump/pg_dump_sort.c b/src/bin/pg_dump/pg_dump_sort.c
index 46461fb6a1..dd5b233196 100644
--- a/src/bin/pg_dump/pg_dump_sort.c
+++ b/src/bin/pg_dump/pg_dump_sort.c
@@ -75,6 +75,7 @@ enum dbObjectTypePriorities
 	PRIO_CONSTRAINT,
 	PRIO_INDEX,
 	PRIO_INDEX_ATTACH,
+	PRIO_INDEX_CLUSTER_ON,
 	PRIO_STATSEXT,
 	PRIO_RULE,
 	PRIO_TRIGGER,
@@ -108,6 +109,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_ATTRDEF,				/* DO_ATTRDEF */
 	PRIO_INDEX,					/* DO_INDEX */
 	PRIO_INDEX_ATTACH,			/* DO_INDEX_ATTACH */
+	PRIO_INDEX_CLUSTER_ON,			/* DO_INDEX_CLUSTER_ON */
 	PRIO_STATSEXT,				/* DO_STATSEXT */
 	PRIO_RULE,					/* DO_RULE */
 	PRIO_TRIGGER,				/* DO_TRIGGER */
@@ -136,6 +138,7 @@ static const int dbObjectTypePriority[] =
 	PRIO_PUBLICATION,			/* DO_PUBLICATION */
 	PRIO_PUBLICATION_REL,		/* DO_PUBLICATION_REL */
 	PRIO_SUBSCRIPTION			/* DO_SUBSCRIPTION */
+
 };
 
 StaticAssertDecl(lengthof(dbObjectTypePriority) == (DO_SUBSCRIPTION + 1),
@@ -1348,6 +1351,11 @@ describeDumpableObject(DumpableObject *obj, char *buf, int bufsize)
 					 "INDEX ATTACH %s  (ID %d)",
 					 obj->name, obj->dumpId);
 			return;
+		case DO_INDEX_CLUSTER_ON:
+			snprintf(buf, bufsize,
+					 "INDEX CLUSTER ON %s  (ID %d)",
+					 obj->name, obj->dumpId);
+			return;
 		case DO_STATSEXT:
 			snprintf(buf, bufsize,
 					 "STATISTICS %s  (ID %d OID %u)",
-- 
2.17.0

From 3d846ff4f4f311ade1e8c7afe1e7481249ca6d89 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v10 2/8] Implement CLUSTER of partitioned table..

This requires either specification of a partitioned index on which to cluster,
or that an partitioned index was previously set clustered.

VACUUM (including vacuum full) has recursed into partition hierarchies since
partitions were introduced in v10 (3c3bb9933).
---
 doc/src/sgml/ref/cluster.sgml         |   7 ++
 src/backend/commands/cluster.c        | 173 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  58 ++++++++-
 src/test/regress/sql/cluster.sql      |  24 +++-
 6 files changed, 209 insertions(+), 55 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 0d9720fd8e..17509b35eb 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -197,6 +197,13 @@ CLUSTER [VERBOSE]
     in the <structname>pg_stat_progress_cluster</structname> view. See
     <xref linkend="cluster-progress-reporting"/> for details.
   </para>
+
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    partition of the specified partitioned index or (if not specified) the
+    partitioned index marked as clustered.
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..0c08ac56dc 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -135,7 +140,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 											AccessExclusiveLock,
 											0,
 											RangeVarCallbackOwnsTable, NULL);
-		rel = table_open(tableOid, NoLock);
+		rel = table_open(tableOid, ShareUpdateExclusiveLock);
 
 		/*
 		 * Reject clustering a remote temp table ... their local buffer
@@ -146,14 +151,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -189,10 +186,34 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		}
 
 		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		table_close(rel, ShareUpdateExclusiveLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +223,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +245,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -352,9 +351,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -398,8 +398,13 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
+	{
 		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
 
+		/* Mark the index as clustered */
+		mark_index_clustered(OldHeap, indexOid, true);
+	}
+
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
 	 * been populated from its query. No harm is done because there is no data
@@ -415,6 +420,14 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	/* For a partitioned rel, we're done. */
+	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
+	{
+		relation_close(OldHeap, AccessExclusiveLock);
+		pgstat_progress_end_command();
+		return;
+	}
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -483,6 +496,9 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	 * the worst consequence of following broken HOT chains would be that we
 	 * might put recently-dead tuples out-of-order in the new table, and there
 	 * is little harm in that.)
+	 *
+	 * This also refuses to cluster on an "incomplete" partitioned index
+	 * created with "ON ONLY".
 	 */
 	if (!OldIndex->rd_index->indisvalid)
 		ereport(ERROR,
@@ -507,12 +523,6 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	Relation	pg_index;
 	ListCell   *index;
 
-	/* Disallow applying to a partitioned table */
-	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot mark index clustered in partitioned table")));
-
 	/*
 	 * If the index is already marked clustered, no need to do anything.
 	 */
@@ -584,10 +594,6 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
-	if (OidIsValid(indexOid))
-		mark_index_clustered(OldHeap, indexOid, true);
-
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
 	is_system_catalog = IsSystemRelation(OldHeap);
@@ -1582,3 +1588,76 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and associated index, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	/*
+	 * We have to build the list in a different memory context so it will
+	 * survive the cross-transaction processing
+	 */
+	old_context = MemoryContextSwitchTo(cluster_context);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		/*
+		 * Partitioned rels (including the top indexOid) are included,
+		 * so as to be processed by cluster_rel, which calls
+		 * check_index_is_clusterable() and mark_index_clustered().
+		 */
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+	}
+
+	MemoryContextSwitchTo(old_context);
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index a053bc1e45..3fd192b8d2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -588,6 +588,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..c30ca01726 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e46a66952f..8fb496434e 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -444,14 +444,62 @@ DROP TABLE clustertest;
 CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
-ERROR:  cannot mark index clustered in partitioned table
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+      relname      | relkind | indisclustered 
+-------------------+---------+----------------
+ clstrpart11_a_idx | i       | t
+ clstrpart12_a_idx | I       | t
+ clstrpart1_a_idx  | I       | t
+ clstrpart2_a_idx  | i       | t
+ clstrpart33_a_idx | i       | t
+ clstrpart3_a_idx  | I       | t
+ clstrpart_idx     | I       | t
+(7 rows)
+
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a) CLUSTER
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index aee9cf83e0..57fc661863 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -202,12 +202,30 @@ CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Check that clustering sets new indisclustered:
+SELECT relname, relkind, indisclustered FROM pg_partition_tree('clstrpart_idx'::regclass) AS tree JOIN pg_index i ON i.indexrelid=tree.relid JOIN pg_class c ON c.oid=indexrelid ORDER BY relname COLLATE "C";
+CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitioned
+CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
+CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From c2c0faeed2612aa0d947058e31fc53e54dacd7e6 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Mon, 8 Feb 2021 20:45:26 -0600
Subject: [PATCH v10 3/8] f! progress reporting..

This follows the precedent of pg_stat_progress_create_index, which
simultaneously shows the progress of 1) the leaf partition, and 2) the overall
progress as partitions_done / partitions_total.

This also includes current_child_index_relid, but the create_index view
doesn't, so maybe this shouldn't, either.
---
 doc/src/sgml/monitoring.sgml         | 21 +++++++++++
 src/backend/catalog/system_views.sql |  4 +-
 src/backend/commands/cluster.c       | 55 ++++++++++++++++------------
 src/backend/commands/vacuum.c        |  5 +++
 src/include/commands/progress.h      |  3 ++
 src/test/regress/expected/rules.out  |  4 +-
 6 files changed, 67 insertions(+), 25 deletions(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index 56018745c8..28493c7931 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -6293,6 +6293,27 @@ SELECT pg_stat_get_backend_pid(s.backendid) AS pid,
        is <literal>rebuilding index</literal>.
       </para></entry>
      </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>total_partitions</structfield> <type>bigint</type>
+      </para>
+       When clustering a partitioned table, this column is set to the total
+       number of partitions to be clustered.
+      <para>
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>done_partitions</structfield> <type>bigint</type>
+      </para>
+      <para>
+       When clustering a partitioned table, this column is set to the number
+       of partitions which have been clustered.
+      </para></entry>
+     </row>
+
     </tbody>
    </tgroup>
   </table>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 5f2541d316..0256809f06 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1142,7 +1142,9 @@ CREATE VIEW pg_stat_progress_cluster AS
         S.param5 AS heap_tuples_written,
         S.param6 AS heap_blks_total,
         S.param7 AS heap_blks_scanned,
-        S.param8 AS index_rebuild_count
+        S.param8 AS index_rebuild_count,
+        S.param18 AS partitions_total,
+        S.param19 AS partitions_done
     FROM pg_stat_get_progress_info('CLUSTER') AS S
         LEFT JOIN pg_database D ON S.datid = D.oid;
 
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 0c08ac56dc..7d8d1d8a69 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -77,7 +77,7 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
-static void cluster_multiple_rels(List *rvs, int options);
+static void cluster_multiple_rels(List *rvs, int options, bool ispartitioned);
 
 
 /*---------------------------------------------------------------------------
@@ -188,16 +188,26 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		/* close relation, keep lock till commit */
 		table_close(rel, ShareUpdateExclusiveLock);
 
+		pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
 		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
 		{
 			/* Do the job. */
+			pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+					PROGRESS_CLUSTER_COMMAND_CLUSTER);
 			cluster_rel(tableOid, indexOid, &params);
+			pgstat_progress_end_command();
 		}
 		else
 		{
 			List	   *rvs;
 			MemoryContext cluster_context;
 
+			int64		progress_val[2];
+			const int	progress_index[2] = {
+				PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_PARTITIONS_TOTAL,
+			};
+
 			/* Refuse to hold strong locks in a user transaction */
 			PreventInTransactionBlock(isTopLevel, "CLUSTER");
 
@@ -206,7 +216,15 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 												ALLOCSET_DEFAULT_SIZES);
 
 			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
-			cluster_multiple_rels(rvs, params.options);
+
+			/* Report command and number of partitions */
+			progress_val[0] = PROGRESS_CLUSTER_COMMAND_CLUSTER;
+			/* XXX: rvs includes the parent, which is not a "partition" */
+			progress_val[1] = list_length(rvs);
+
+			pgstat_progress_update_multi_param(2, progress_index, progress_val);
+			cluster_multiple_rels(rvs, params.options, true);
+			pgstat_progress_end_command();
 
 			/* Start a new transaction for the cleanup work. */
 			StartTransactionCommand();
@@ -245,7 +263,11 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
+
+		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_COMMAND_CLUSTER);
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED, false);
+		pgstat_progress_end_command();
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -282,14 +304,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	/* Check for user-requested abort. */
 	CHECK_FOR_INTERRUPTS();
 
-	pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
-	if (OidIsValid(indexOid))
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_CLUSTER);
-	else
-		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
-									 PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
-
 	/*
 	 * We grab exclusive access to the target rel and index for the duration
 	 * of the transaction.  (This is redundant for the single-transaction
@@ -300,10 +314,7 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* If the table has gone away, we can skip processing it */
 	if (!OldHeap)
-	{
-		pgstat_progress_end_command();
 		return;
-	}
 
 	/*
 	 * Since we may open a new transaction for each relation, we have to check
@@ -319,7 +330,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (!pg_class_ownercheck(tableOid, GetUserId()))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -334,7 +344,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
 			relation_close(OldHeap, AccessExclusiveLock);
-			pgstat_progress_end_command();
 			return;
 		}
 
@@ -346,7 +355,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid)))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 
@@ -357,7 +365,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
-				pgstat_progress_end_command();
 				return;
 			}
 		}
@@ -416,7 +423,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		!RelationIsPopulated(OldHeap))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -424,7 +430,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	if (!RELKIND_HAS_STORAGE(get_rel_relkind(tableOid)))
 	{
 		relation_close(OldHeap, AccessExclusiveLock);
-		pgstat_progress_end_command();
 		return;
 	}
 
@@ -440,8 +445,6 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	rebuild_relation(OldHeap, indexOid, verbose);
 
 	/* NB: rebuild_relation does table_close() on OldHeap */
-
-	pgstat_progress_end_command();
 }
 
 /*
@@ -1632,9 +1635,10 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
 
 /* Cluster each relation in a separate transaction */
 static void
-cluster_multiple_rels(List *rvs, int options)
+cluster_multiple_rels(List *rvs, int options, bool ispartitioned)
 {
 	ListCell *lc;
+	off_t	  childnum = 0;
 
 	/* Commit to get out of starting transaction */
 	PopActiveSnapshot();
@@ -1657,6 +1661,11 @@ cluster_multiple_rels(List *rvs, int options)
 		cluster_rel(rvtc->tableOid, rvtc->indexOid,
 					&cluster_params);
 
+		if (ispartitioned)
+			pgstat_progress_update_param(PROGRESS_CLUSTER_PARTITIONS_DONE,
+					++childnum);
+
+
 		PopActiveSnapshot();
 		CommitTransactionCommand();
 	}
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 662aff04b4..1d8a7ca774 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -37,6 +37,7 @@
 #include "catalog/pg_namespace.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
+#include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -1937,7 +1938,11 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams *params)
 			cluster_params.options |= CLUOPT_VERBOSE;
 
 		/* VACUUM FULL is now a variant of CLUSTER; see cluster.c */
+		pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, relid);
+		pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
+				PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
 		cluster_rel(relid, InvalidOid, &cluster_params);
+		pgstat_progress_end_command();
 	}
 	else
 		table_relation_vacuum(onerel, params, vac_strategy);
diff --git a/src/include/commands/progress.h b/src/include/commands/progress.h
index c6b139d57d..d85781ae0b 100644
--- a/src/include/commands/progress.h
+++ b/src/include/commands/progress.h
@@ -60,6 +60,9 @@
 #define PROGRESS_CLUSTER_TOTAL_HEAP_BLKS		5
 #define PROGRESS_CLUSTER_HEAP_BLKS_SCANNED		6
 #define PROGRESS_CLUSTER_INDEX_REBUILD_COUNT	7
+/* Need to avoid the CREATE INDEX params */
+#define PROGRESS_CLUSTER_PARTITIONS_TOTAL	17
+#define PROGRESS_CLUSTER_PARTITIONS_DONE	18
 
 /* Phases of cluster (as advertised via PROGRESS_CLUSTER_PHASE) */
 #define PROGRESS_CLUSTER_PHASE_SEQ_SCAN_HEAP	1
diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out
index 9b59a7b4a5..a8bcc599ac 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -1943,7 +1943,9 @@ pg_stat_progress_cluster| SELECT s.pid,
     s.param5 AS heap_tuples_written,
     s.param6 AS heap_blks_total,
     s.param7 AS heap_blks_scanned,
-    s.param8 AS index_rebuild_count
+    s.param8 AS index_rebuild_count,
+    s.param18 AS partitions_total,
+    s.param19 AS partitions_done
    FROM (pg_stat_get_progress_info('CLUSTER'::text) s(pid, datid, relid, param1, param2, param3, param4, param5, param6, param7, param8, param9, param10, param11, param12, param13, param14, param15, param16, param17, param18, param19, param20)
      LEFT JOIN pg_database d ON ((s.datid = d.oid)));
 pg_stat_progress_copy| SELECT s.pid,
-- 
2.17.0

From c98512d58e64f98ae87558da594d379759df80e1 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 22:11:12 -0500
Subject: [PATCH v10 4/8] Propagate changes to indisclustered to child/parents

---
 src/backend/commands/cluster.c        | 110 ++++++++++++++++----------
 src/backend/commands/indexcmds.c      |   2 +
 src/test/regress/expected/cluster.out |  46 +++++++++++
 src/test/regress/sql/cluster.sql      |  11 +++
 4 files changed, 126 insertions(+), 43 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 7d8d1d8a69..dd8014c206 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -74,6 +74,7 @@ static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
 static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
+static void set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
 static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
 		Oid indexOid);
@@ -513,66 +514,89 @@ check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMOD
 	index_close(OldIndex, NoLock);
 }
 
+/*
+ * Helper for mark_index_clustered
+ * Mark a single index as clustered or not.
+ * pg_index is passed by caller to avoid repeatedly re-opening it.
+ */
+static void
+set_indisclustered(Oid indexOid, bool isclustered, Relation pg_index)
+{
+	HeapTuple	indexTuple;
+	Form_pg_index indexForm;
+
+	indexTuple = SearchSysCacheCopy1(INDEXRELID,
+									ObjectIdGetDatum(indexOid));
+	if (!HeapTupleIsValid(indexTuple))
+		elog(ERROR, "cache lookup failed for index %u", indexOid);
+	indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+
+	/* this was checked earlier, but let's be real sure */
+	if (isclustered && !indexForm->indisvalid)
+		elog(ERROR, "cannot cluster on invalid index %u", indexOid);
+
+	indexForm->indisclustered = isclustered;
+	CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
+	heap_freetuple(indexTuple);
+}
+
 /*
  * mark_index_clustered: mark the specified index as the one clustered on
  *
- * With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
+ * With indexOid == InvalidOid, mark all indexes of rel not-clustered.
+ * Otherwise, mark children of the clustered index as clustered, and parents of
+ * other indexes as unclustered.
+ * We wish to maintain the following properties:
+ * 1) Only one index on a relation can be marked clustered at once
+ * 2) If a partitioned index is clustered, then all its children must be
+ *     clustered.
  */
 void
 mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 {
-	HeapTuple	indexTuple;
-	Form_pg_index indexForm;
-	Relation	pg_index;
-	ListCell   *index;
-
-	/*
-	 * If the index is already marked clustered, no need to do anything.
-	 */
-	if (OidIsValid(indexOid))
-	{
-		if (get_index_isclustered(indexOid))
-			return;
-	}
+	ListCell	*lc, *lc2;
+	List		*indexes;
+	Relation	pg_index = table_open(IndexRelationId, RowExclusiveLock);
+	List		*inh = find_all_inheritors(RelationGetRelid(rel),
+											ShareRowExclusiveLock, NULL);
 
 	/*
 	 * Check each index of the relation and set/clear the bit as needed.
+	 * Iterate over the relation's children rather than the index's children
+	 * since we need to unset cluster for indexes on intermediate children,
+	 * too.
 	 */
-	pg_index = table_open(IndexRelationId, RowExclusiveLock);
-
-	foreach(index, RelationGetIndexList(rel))
+	foreach(lc, inh)
 	{
-		Oid			thisIndexOid = lfirst_oid(index);
-
-		indexTuple = SearchSysCacheCopy1(INDEXRELID,
-										 ObjectIdGetDatum(thisIndexOid));
-		if (!HeapTupleIsValid(indexTuple))
-			elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
-		indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		Oid			inhrelid = lfirst_oid(lc);
+		Relation	thisrel = table_open(inhrelid, ShareRowExclusiveLock);
 
-		/*
-		 * Unset the bit if set.  We know it's wrong because we checked this
-		 * earlier.
-		 */
-		if (indexForm->indisclustered)
+		indexes = RelationGetIndexList(thisrel);
+		foreach (lc2, indexes)
 		{
-			indexForm->indisclustered = false;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
-		else if (thisIndexOid == indexOid)
-		{
-			/* this was checked earlier, but let's be real sure */
-			if (!indexForm->indisvalid)
-				elog(ERROR, "cannot cluster on invalid index %u", indexOid);
-			indexForm->indisclustered = true;
-			CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
-		}
+			bool	isclustered;
+			Oid		thisIndexOid = lfirst_oid(lc2);
+			List	*parentoids = get_rel_relispartition(thisIndexOid) ?
+				get_partition_ancestors(thisIndexOid) : NIL;
 
-		InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
-									 InvalidOid, is_internal);
+			/*
+			 * A child of the clustered index must be set clustered;
+			 * indexes which are not children of the clustered index are
+			 * set unclustered
+			 */
+			isclustered = (thisIndexOid == indexOid) ||
+					list_member_oid(parentoids, indexOid);
+			Assert(OidIsValid(indexOid) || !isclustered);
+			set_indisclustered(thisIndexOid, isclustered, pg_index);
+
+			InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
+										 InvalidOid, is_internal);
+		}
 
-		heap_freetuple(indexTuple);
+		list_free(indexes);
+		table_close(thisrel, ShareRowExclusiveLock);
 	}
+	list_free(inh);
 
 	table_close(pg_index, RowExclusiveLock);
 }
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 166374cc0c..7d176c1062 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -25,6 +25,7 @@
 #include "catalog/catalog.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -32,6 +33,7 @@
 #include "catalog/pg_opfamily.h"
 #include "catalog/pg_tablespace.h"
 #include "catalog/pg_type.h"
+#include "commands/cluster.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
 #include "commands/defrem.h"
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 8fb496434e..a2af5c15ec 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -500,6 +500,52 @@ Indexes:
     "clstrpart_idx" btree (a) CLUSTER
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a)
+
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+            Table "public.clstrpart33"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart3 DEFAULT
+Indexes:
+    "clstrpart33_a_idx" btree (a) CLUSTER
+
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
+       Partitioned table "public.clstrpart1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (1) TO (10)
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart1_a_idx" btree (a)
+    "clstrpart1_idx_2" btree (a) CLUSTER
+Number of partitions: 2 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 57fc661863..3b7fa3142f 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -226,6 +226,17 @@ CLUSTER clstrpart1 USING clstrpart1_a_idx; -- partition which is itself partitio
 CLUSTER clstrpart12 USING clstrpart12_a_idx; -- partition which is itself partitioned, no childs
 CLUSTER clstrpart2 USING clstrpart2_a_idx; -- leaf
 \d clstrpart
+-- Test that it recurses to grandchildren:
+\d clstrpart33
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+\d clstrpart33
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+\d clstrpart33
+-- Check that only one child is marked clustered after marking clustered on a different parent
+CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
+\d clstrpart1
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 6badf17a18b344cc1be6dcae195478011889ee43 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 18:58:03 -0600
Subject: [PATCH v10 5/8] Invalidate parent indexes

---
 src/backend/commands/cluster.c        | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 26 ++++++++++++++++++++++++++
 src/test/regress/sql/cluster.sql      |  8 ++++++++
 3 files changed, 55 insertions(+)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index dd8014c206..1b8ff911b0 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -598,6 +598,27 @@ mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
 	}
 	list_free(inh);
 
+	/*
+	 * Set parent of all indexes as unclustered when a rel is unclustered; and,
+	 * when an index is clustered, set parents of all /other/ indexes as
+	 * unclustered.
+	 */
+	indexes = RelationGetIndexList(rel);
+	foreach (lc, indexes)
+	{
+		Oid	thisIndexOid = lfirst_oid(lc);
+
+		if (thisIndexOid == indexOid)
+			continue;
+
+		while (get_rel_relispartition(thisIndexOid))
+		{
+			thisIndexOid = get_partition_parent(thisIndexOid, true);
+			set_indisclustered(thisIndexOid, false, pg_index);
+		}
+	}
+	list_free(indexes);
+
 	table_close(pg_index, RowExclusiveLock);
 }
 
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index a2af5c15ec..c316c41905 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -546,6 +546,32 @@ Indexes:
     "clstrpart1_idx_2" btree (a) CLUSTER
 Number of partitions: 2 (Use \d+ to list them.)
 
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 3b7fa3142f..1cc7c1aaca 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -237,6 +237,14 @@ CREATE INDEX clstrpart1_idx_2 ON clstrpart1(a);
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 CLUSTER ON clstrpart1_idx_2;
 \d clstrpart1
+-- Check that the parent index is marked not clustered after clustering a partition on a different index:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CLUSTER clstrpart1 USING clstrpart1_idx_2;
+\d clstrpart
+-- Check that the parent index is marked not clustered after setting a partition not clustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From 8bb301a35c7319967a204e962a88c47ce15138d5 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Thu, 5 Nov 2020 19:11:41 -0600
Subject: [PATCH v10 6/8] Invalidate parent index cluster on attach

---
 src/backend/commands/indexcmds.c      | 21 +++++++++++++++++++++
 src/test/regress/expected/cluster.out | 14 ++++++++++++++
 src/test/regress/sql/cluster.sql      |  5 +++++
 3 files changed, 40 insertions(+)

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 7d176c1062..bf13bed627 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -4110,6 +4110,27 @@ IndexSetParentIndex(Relation partitionIdx, Oid parentOid)
 	/* set relispartition correctly on the partition */
 	update_relispartition(partRelid, OidIsValid(parentOid));
 
+	/*
+	 * If the attached index is not clustered, invalidate cluster mark on
+	 * any parents
+	 */
+	if ((OidIsValid(parentOid) && get_index_isclustered(parentOid)) ||
+			get_index_isclustered(partRelid))
+	{
+		Relation indrel;
+
+		/* Make relispartition visible */
+		CommandCounterIncrement();
+
+		indrel = table_open(IndexGetRelation(partRelid, false),
+				ShareUpdateExclusiveLock);
+		mark_index_clustered(indrel,
+				get_index_isclustered(partRelid) ? partRelid : InvalidOid,
+				true);
+		table_close(indrel, ShareUpdateExclusiveLock);
+
+	}
+
 	if (fix_dependencies)
 	{
 		/*
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index c316c41905..846975fc06 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -572,6 +572,20 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 3 (Use \d+ to list them.)
 
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 4 (Use \d+ to list them.)
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 1cc7c1aaca..ee14e7079f 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -245,6 +245,11 @@ CLUSTER clstrpart1 USING clstrpart1_idx_2;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ALTER TABLE clstrpart1 SET WITHOUT CLUSTER;
 \d clstrpart
+-- Check that attaching an unclustered index marks the parent unclustered:
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
+ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
+\d clstrpart
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From f0ffdeb4b8fc950003e3426e83ed512f79828442 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 6 Oct 2020 20:40:18 -0500
Subject: [PATCH v10 7/8] Preserve indisclustered on children of clustered,
 partitioned indexes

Note, this takes a parentIndex, but that wasn't previously used ...
UpdateIndexRelation(Oid indexoid, Oid heapoid, Oid parentIndexId,
---
 src/backend/catalog/index.c           |  3 ++-
 src/test/regress/expected/cluster.out | 12 ++++++++++++
 src/test/regress/sql/cluster.sql      |  4 ++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index a628b3281c..8e97d88c32 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -615,7 +615,8 @@ UpdateIndexRelation(Oid indexoid,
 	values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
 	values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
 	values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
-	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(false);
+	values[Anum_pg_index_indisclustered - 1] = BoolGetDatum(OidIsValid(parentIndexId) &&
+												get_index_isclustered(parentIndexId));
 	values[Anum_pg_index_indisvalid - 1] = BoolGetDatum(isvalid);
 	values[Anum_pg_index_indcheckxmin - 1] = BoolGetDatum(false);
 	values[Anum_pg_index_indisready - 1] = BoolGetDatum(isready);
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 846975fc06..9429482980 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -586,6 +586,18 @@ Indexes:
     "clstrpart_idx" btree (a)
 Number of partitions: 4 (Use \d+ to list them.)
 
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
+             Table "public.clstrpart4"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition of: clstrpart FOR VALUES FROM (30) TO (40)
+Indexes:
+    "clstrpart4_a_idx" btree (a) CLUSTER
+
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index ee14e7079f..af0849904d 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -250,6 +250,10 @@ ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 CREATE TABLE clstrpart5 (LIKE clstrpart INCLUDING INDEXES);
 ALTER TABLE clstrpart ATTACH PARTITION clstrpart5 FOR VALUES FROM (40)TO(50);
 \d clstrpart
+-- Check that new children inherit clustered mark
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+CREATE TABLE clstrpart4 PARTITION OF clstrpart FOR VALUES FROM (30)TO(40);
+\d clstrpart4
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From a183a1ad79d00e25dfe4912e6c170631b7a0258c Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 Nov 2020 17:34:07 -0600
Subject: [PATCH v10 8/8] pg_dump: partitioned index depend on its partitions

This is required for restoring clustered parent index, which is marked INVALID
until indexes have been built on all its child tables, and it's prohibited to
CLUSTER ON an INVALID index

See also: 8cff4f5348d075e063100071013f00a900c32b0f
---
 src/backend/commands/tablecmds.c | 6 +++---
 src/bin/pg_dump/common.c         | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 88a68a4697..aaf955458c 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -18153,6 +18153,9 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		table_close(idxRel, RowExclusiveLock);
 	}
 
+	/* make sure we see the validation we just did */
+	CommandCounterIncrement();
+
 	/*
 	 * If this index is in turn a partition of a larger index, validating it
 	 * might cause the parent to become valid also.  Try that.
@@ -18164,9 +18167,6 @@ validatePartitionedIndex(Relation partedIdx, Relation partedTbl)
 		Relation	parentIdx,
 					parentTbl;
 
-		/* make sure we see the validation we just did */
-		CommandCounterIncrement();
-
 		parentIdxId = get_partition_parent(RelationGetRelid(partedIdx), false);
 		parentTblId = get_partition_parent(RelationGetRelid(partedTbl), false);
 		parentIdx = relation_open(parentIdxId, AccessExclusiveLock);
diff --git a/src/bin/pg_dump/common.c b/src/bin/pg_dump/common.c
index 1a261a5545..cdfba058fc 100644
--- a/src/bin/pg_dump/common.c
+++ b/src/bin/pg_dump/common.c
@@ -429,6 +429,12 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			attachinfo[k].parentIdx = parentidx;
 			attachinfo[k].partitionIdx = index;
 
+			/*
+			 * We want dependencies from parent to partition (so that the
+			 * partition index is created first)
+			 */
+			addObjectDependency(&parentidx->dobj, index->dobj.dumpId);
+
 			/*
 			 * We must state the DO_INDEX_ATTACH object's dependencies
 			 * explicitly, since it will not match anything in pg_depend.
@@ -446,6 +452,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 			 */
 			addObjectDependency(&attachinfo[k].dobj, index->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj, parentidx->dobj.dumpId);
+			// addObjectDependency(&parentidx->dobj, attachinfo[k].dobj.dumpId);
+
 			addObjectDependency(&attachinfo[k].dobj,
 								index->indextable->dobj.dumpId);
 			addObjectDependency(&attachinfo[k].dobj,
-- 
2.17.0

From d2e7daf9c05cd3c20c60f5e35c0d6b2612d75d1b Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v11] Implement CLUSTER of partitioned table..

For now, partitioned indexes cannot be marked clustered, so clustering requires
specification of a partitioned index on the partitioned table.

VACUUM (including vacuum full) has recursed into partitione tables since
partitioning were introduced in v10 (3c3bb9933).  See expand_vacuum_rel().

See also a556549d7 and 19de0ab23.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 170 +++++++++++++++++++-------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  46 ++++++-
 src/test/regress/sql/cluster.sql      |  22 +++-
 6 files changed, 197 insertions(+), 49 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 86f5fdc469..b3463ae5c4 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -196,6 +196,12 @@ CLUSTER [VERBOSE]
     in the <structname>pg_stat_progress_cluster</structname> view. See
     <xref linkend="cluster-progress-reporting"/> for details.
   </para>
+
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    partition of the specified partitioned index (which must be specified).
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 9d22f648a8..c5923c5217 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -131,6 +136,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		Relation	rel;
 
 		/* Find, lock, and check permissions on the table */
+		/* Obtain AEL now to avoid lock-upgrade hazard in the single-transaction case */
 		tableOid = RangeVarGetRelidExtended(stmt->relation,
 											AccessExclusiveLock,
 											0,
@@ -146,14 +152,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -188,11 +186,45 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 								stmt->indexname, stmt->relation->relname)));
 		}
 
-		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* close relation, keep lock till commit */
+			table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+
+			/*
+			 * For now, partitioned indexes are not actually marked clustered.
+			 */
+			check_index_is_clusterable(rel, indexOid, true, AccessShareLock);
+
+			/* close relation, releasing lock on parent table */
+			table_close(rel, AccessExclusiveLock);
+
+			/* Do the job. */
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +234,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +256,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -327,10 +337,11 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		/*
 		 * Silently skip a temp table for a remote session.  Only doing this
 		 * check in the "recheck" case is appropriate (which currently means
-		 * somebody is executing a database-wide CLUSTER), because there is
-		 * another check in cluster() which will stop any attempt to cluster
-		 * remote temp tables by name.  There is another check in cluster_rel
-		 * which is redundant, but we leave it for extra safety.
+		 * somebody is executing a database-wide CLUSTER or on a partitioned
+		 * table), because there is another check in cluster() which will stop
+		 * any attempt to cluster remote temp tables by name.  There is another
+		 * check in cluster_rel which is redundant, but we leave it for extra
+		 * safety.
 		 */
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
@@ -352,9 +363,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -415,6 +427,9 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	// Should silently skip this rather than assert ?
+	Assert(RELKIND_HAS_STORAGE(OldHeap->rd_rel->relkind));
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -585,8 +600,8 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
 	if (OidIsValid(indexOid))
+		/* Mark the correct index as clustered */
 		mark_index_clustered(OldHeap, indexOid, true);
 
 	/* Remember info about rel before closing OldHeap */
@@ -1604,3 +1619,74 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and their associated indexes, where each index is a
+ * partition of the given index
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	/*
+	 * We have to build the list in a different memory context so it will
+	 * survive the cross-transaction processing
+	 */
+	old_context = MemoryContextSwitchTo(cluster_context);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		if (!RELKIND_HAS_STORAGE(get_rel_relkind(indexrelid)))
+			continue;
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+	}
+
+	MemoryContextSwitchTo(old_context);
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 5cd5838668..c377511278 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -599,6 +599,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index b64d3bc204..d400b6e937 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e46a66952f..7461e1c090 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -444,14 +444,52 @@ DROP TABLE clustertest;
 CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+CLUSTER clstrpart USING clstrpart_idx;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+CLUSTER clstrpart;
+ERROR:  there is no previously clustered index for table "clstrpart"
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ERROR:  cannot mark index clustered in partitioned table
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ERROR:  cannot mark index clustered in partitioned table
-CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
-DROP TABLE clstrpart;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index aee9cf83e0..f31f8ef2b2 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -202,12 +202,28 @@ CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
-DROP TABLE clstrpart;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+CLUSTER clstrpart;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 
 -- Test CLUSTER with external tuplesorting
 
-- 
2.17.0

From cbeb98a016a05738007c98ef0a3828bdedf83d24 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Sun, 7 Jun 2020 16:58:42 -0500
Subject: [PATCH v11] Implement CLUSTER of partitioned table..

VACUUM (including vacuum full) has recursed into partitioned tables since
partitioning were introduced in v10 (3c3bb9933).  See expand_vacuum_rel().

For VACUUM FULL, vacuum_rel() calls cluster_rel() for each partition.
This patch is to make cluster() do all the same stuff before calling
cluster_rel().

For now, partitioned indexes cannot be marked clustered, so clustering requires
specification of a partitioned index on the partitioned table.

See also a556549d7 and 19de0ab23.
---
 doc/src/sgml/ref/cluster.sgml         |   6 +
 src/backend/commands/cluster.c        | 177 ++++++++++++++++++++------
 src/bin/psql/tab-complete.c           |   1 +
 src/include/commands/cluster.h        |   1 +
 src/test/regress/expected/cluster.out |  45 ++++++-
 src/test/regress/sql/cluster.sql      |  21 ++-
 6 files changed, 204 insertions(+), 47 deletions(-)

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 86f5fdc469b..b3463ae5c46 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -196,6 +196,12 @@ CLUSTER [VERBOSE]
     in the <structname>pg_stat_progress_cluster</structname> view. See
     <xref linkend="cluster-progress-reporting"/> for details.
   </para>
+
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    partition of the specified partitioned index (which must be specified).
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 61853e6dec4..196c7f7eeb2 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+		Oid indexOid);
+static void cluster_multiple_rels(List *rvs, int options);
 
 
 /*---------------------------------------------------------------------------
@@ -131,6 +136,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		Relation	rel;
 
 		/* Find, lock, and check permissions on the table */
+		/* Obtain AEL now to avoid lock-upgrade hazard in the single-transaction case */
 		tableOid = RangeVarGetRelidExtended(stmt->relation,
 											AccessExclusiveLock,
 											0,
@@ -146,14 +152,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -188,11 +186,50 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 								stmt->indexname, stmt->relation->relname)));
 		}
 
-		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* close relation, keep lock till commit */
+			table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+		}
+		else
+		{
+			List	   *rvs;
+			MemoryContext cluster_context;
+
+			/*
+			 * Expand partitioned relations for CLUSTER (the corresponding
+			 * thing for VACUUM FULL happens in and around expand_vacuum_rel()
+			 */
+
+			/* Refuse to hold strong locks in a user transaction */
+			PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+			cluster_context = AllocSetContextCreate(PortalContext,
+												"Cluster",
+												ALLOCSET_DEFAULT_SIZES);
+
+			rvs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+
+			/*
+			 * For now, partitioned indexes are not actually marked clustered.
+			 */
+			check_index_is_clusterable(rel, indexOid, true, AccessShareLock);
+
+			/* close relation, releasing lock on parent table */
+			table_close(rel, AccessExclusiveLock);
+
+			/* Do the job. */
+			cluster_multiple_rels(rvs, params.options);
+
+			/* Start a new transaction for the cleanup work. */
+			StartTransactionCommand();
+
+			/* Clean up working storage */
+			MemoryContextDelete(cluster_context);
+		}
 	}
 	else
 	{
@@ -202,7 +239,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 */
 		MemoryContext cluster_context;
 		List	   *rvs;
-		ListCell   *rv;
 
 		/*
 		 * We cannot run this form of CLUSTER inside a user transaction block;
@@ -225,28 +261,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 		 * cluster_context.
 		 */
 		rvs = get_tables_to_cluster(cluster_context);
-
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
-
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
-
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+		cluster_multiple_rels(rvs, params.options | CLUOPT_RECHECK_ISCLUSTERED);
 
 		/* Start a new transaction for the cleanup work. */
 		StartTransactionCommand();
@@ -327,10 +342,11 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		/*
 		 * Silently skip a temp table for a remote session.  Only doing this
 		 * check in the "recheck" case is appropriate (which currently means
-		 * somebody is executing a database-wide CLUSTER), because there is
-		 * another check in cluster() which will stop any attempt to cluster
-		 * remote temp tables by name.  There is another check in cluster_rel
-		 * which is redundant, but we leave it for extra safety.
+		 * somebody is executing a database-wide CLUSTER or on a partitioned
+		 * table), because there is another check in cluster() which will stop
+		 * any attempt to cluster remote temp tables by name.  There is another
+		 * check in cluster_rel which is redundant, but we leave it for extra
+		 * safety.
 		 */
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
@@ -352,9 +368,10 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set, if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+					!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -415,6 +432,9 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	// Should silently skip this rather than assert ?
+	Assert(RELKIND_HAS_STORAGE(OldHeap->rd_rel->relkind));
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -585,8 +605,8 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
 	if (OidIsValid(indexOid))
+		/* Mark the correct index as clustered */
 		mark_index_clustered(OldHeap, indexOid, true);
 
 	/* Remember info about rel before closing OldHeap */
@@ -1604,3 +1624,76 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	return rvs;
 }
+
+/*
+ * Return a List of tables and their associated indexes, where each index is a
+ * partition of the given index
+ * We're called with a lock held on the parent table.
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List		*inhoids;
+	ListCell	*lc;
+	List		*rvs = NIL;
+	MemoryContext	old_context;
+
+	/* Do not lock the children until they're processed. */
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	/*
+	 * We have to build the list in a different memory context so it will
+	 * survive the cross-transaction processing
+	 */
+	old_context = MemoryContextSwitchTo(cluster_context);
+
+	foreach(lc, inhoids)
+	{
+		Oid		indexrelid = lfirst_oid(lc);
+		Oid		relid = IndexGetRelation(indexrelid, false);
+		RelToCluster	*rvtc;
+
+		if (!RELKIND_HAS_STORAGE(get_rel_relkind(indexrelid)))
+			continue;
+
+		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rvtc->tableOid = relid;
+		rvtc->indexOid = indexrelid;
+		rvs = lappend(rvs, rvtc);
+	}
+
+	MemoryContextSwitchTo(old_context);
+	return rvs;
+}
+
+/* Cluster each relation in a separate transaction */
+static void
+cluster_multiple_rels(List *rvs, int options)
+{
+	ListCell *lc;
+
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
+
+	/* Ok, now that we've got them all, cluster them one by one */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
+		ClusterParams cluster_params = { .options = options, };
+
+		/* Start a new transaction for each relation. */
+		StartTransactionCommand();
+
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_params.options |= CLUOPT_RECHECK;
+		cluster_rel(rvtc->tableOid, rvtc->indexOid,
+					&cluster_params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
+	}
+}
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 39be6f556a8..9944f21f71c 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -599,6 +599,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index 3db375d7cc7..0605b053b61 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -22,6 +22,7 @@
 /* flag bits for ClusterParams->flags */
 #define CLUOPT_RECHECK 0x01		/* recheck relation state */
 #define CLUOPT_VERBOSE 0x02		/* print progress info */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04	/* recheck relation state for indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e46a66952f0..3f2758d13f6 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -444,13 +444,52 @@ DROP TABLE clustertest;
 CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+CLUSTER clstrpart USING clstrpart_idx;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+CLUSTER clstrpart;
+ERROR:  there is no previously clustered index for table "clstrpart"
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ERROR:  cannot mark index clustered in partitioned table
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ERROR:  cannot mark index clustered in partitioned table
-CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
 DROP TABLE clstrpart;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index aee9cf83e04..74118993a82 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -202,11 +202,28 @@ CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+CLUSTER clstrpart;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 DROP TABLE clstrpart;
 
 -- Test CLUSTER with external tuplesorting
-- 
2.17.1

diff --git a/doc/src/sgml/ref/cluster.sgml b/doc/src/sgml/ref/cluster.sgml
index 86f5fdc469..b3463ae5c4 100644
--- a/doc/src/sgml/ref/cluster.sgml
+++ b/doc/src/sgml/ref/cluster.sgml
@@ -196,6 +196,12 @@ CLUSTER [VERBOSE]
     in the <structname>pg_stat_progress_cluster</structname> view. See
     <xref linkend="cluster-progress-reporting"/> for details.
   </para>
+
+   <para>
+    Clustering a partitioned table clusters each of its partitions using the
+    partition of the specified partitioned index (which must be specified).
+   </para>
+
  </refsect1>
 
  <refsect1>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 02a7e94bf9..8417cbdb67 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -32,7 +32,9 @@
 #include "catalog/index.h"
 #include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
+#include "catalog/pg_inherits.h"
 #include "catalog/toasting.h"
 #include "commands/cluster.h"
 #include "commands/defrem.h"
@@ -73,6 +75,9 @@ static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
 							bool verbose, bool *pSwapToastByContent,
 							TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
 static List *get_tables_to_cluster(MemoryContext cluster_context);
+static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
+											   Oid indexOid);
+static void cluster_multiple_rels(List *rvs, ClusterParams *params);
 
 
 /*---------------------------------------------------------------------------
@@ -105,6 +110,10 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 	ListCell   *lc;
 	ClusterParams params = {0};
 	bool		verbose = false;
+	Relation	rel = NULL;
+	Oid			indexOid = InvalidOid;
+	MemoryContext cluster_context;
+	List	   *rtcs;
 
 	/* Parse option list */
 	foreach(lc, stmt->params)
@@ -126,11 +135,13 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 	if (stmt->relation != NULL)
 	{
 		/* This is the single-relation case. */
-		Oid			tableOid,
-					indexOid = InvalidOid;
-		Relation	rel;
+		Oid			tableOid;
 
-		/* Find, lock, and check permissions on the table */
+		/*
+		 * Find, lock, and check permissions on the table.  We obtain
+		 * AccessExclusiveLock right away to avoid lock-upgrade hazard in the
+		 * single-transaction case.
+		 */
 		tableOid = RangeVarGetRelidExtended(stmt->relation,
 											AccessExclusiveLock,
 											0,
@@ -146,14 +157,6 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 					 errmsg("cannot cluster temporary tables of other sessions")));
 
-		/*
-		 * Reject clustering a partitioned table.
-		 */
-		if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot cluster a partitioned table")));
-
 		if (stmt->indexname == NULL)
 		{
 			ListCell   *index;
@@ -188,71 +191,100 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 								stmt->indexname, stmt->relation->relname)));
 		}
 
-		/* close relation, keep lock till commit */
-		table_close(rel, NoLock);
+		if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
+		{
+			/* close relation, keep lock till commit */
+			table_close(rel, NoLock);
 
-		/* Do the job. */
-		cluster_rel(tableOid, indexOid, &params);
+			/* Do the job. */
+			cluster_rel(tableOid, indexOid, &params);
+
+			return;
+		}
+	}
+
+	/*
+	 * By here, we know we are in a multi-table situation.  In order to avoid
+	 * holding locks for too long, we want to process each table in its own
+	 * transaction.  This forces us to disallow running inside a user
+	 * transaction block.
+	 */
+	PreventInTransactionBlock(isTopLevel, "CLUSTER");
+
+	/* Also, we need a memory context to hold our list of relations */
+	cluster_context = AllocSetContextCreate(PortalContext,
+											"Cluster",
+											ALLOCSET_DEFAULT_SIZES);
+
+	/*
+	 * Either we're processing a partitioned table, or we were not given any
+	 * table name at all.  In either case, obtain a list of relations to
+	 * process.
+	 *
+	 * In the former case, an index name must have been given, so we don't
+	 * need to recheck its "indisclustered" bit, but we have to check that it
+	 * is an index that we can cluster on.  In the latter case, we set the
+	 * option bit to have indisclustered verified.
+	 *
+	 * Rechecking the relation itself is necessary here in all cases.
+	 */
+	params.options |= CLUOPT_RECHECK;
+	if (rel != NULL)
+	{
+		check_index_is_clusterable(rel, indexOid, true, AccessShareLock);
+		rtcs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
+
+		/* close relation, releasing lock on parent table */
+		table_close(rel, AccessExclusiveLock);
 	}
 	else
 	{
-		/*
-		 * This is the "multi relation" case. We need to cluster all tables
-		 * that have some index with indisclustered set.
-		 */
-		MemoryContext cluster_context;
-		List	   *rvs;
-		ListCell   *rv;
+		rtcs = get_tables_to_cluster(cluster_context);
+		params.options |= CLUOPT_RECHECK_ISCLUSTERED;
+	}
 
-		/*
-		 * We cannot run this form of CLUSTER inside a user transaction block;
-		 * we'd be holding locks way too long.
-		 */
-		PreventInTransactionBlock(isTopLevel, "CLUSTER");
+	/* Do the job. */
+	cluster_multiple_rels(rtcs, &params);
 
-		/*
-		 * Create special memory context for cross-transaction storage.
-		 *
-		 * Since it is a child of PortalContext, it will go away even in case
-		 * of error.
-		 */
-		cluster_context = AllocSetContextCreate(PortalContext,
-												"Cluster",
-												ALLOCSET_DEFAULT_SIZES);
+	/* Start a new transaction for the cleanup work. */
+	StartTransactionCommand();
 
-		/*
-		 * Build the list of relations to cluster.  Note that this lives in
-		 * cluster_context.
-		 */
-		rvs = get_tables_to_cluster(cluster_context);
+	/* Clean up working storage */
+	MemoryContextDelete(cluster_context);
+}
 
-		/* Commit to get out of starting transaction */
-		PopActiveSnapshot();
-		CommitTransactionCommand();
+/*
+ * Given a list of relations to cluster, process each of them in a separate
+ * transaction.
+ *
+ * We expect to be in a transaction at start, but there isn't one when we
+ * return.
+ */
+static void
+cluster_multiple_rels(List *rvs, ClusterParams *params)
+{
+	ListCell   *lc;
 
-		/* Ok, now that we've got them all, cluster them one by one */
-		foreach(rv, rvs)
-		{
-			RelToCluster *rvtc = (RelToCluster *) lfirst(rv);
-			ClusterParams cluster_params = params;
+	/* Commit to get out of starting transaction */
+	PopActiveSnapshot();
+	CommitTransactionCommand();
 
-			/* Start a new transaction for each relation. */
-			StartTransactionCommand();
-			/* functions in indexes may want a snapshot set */
-			PushActiveSnapshot(GetTransactionSnapshot());
-			/* Do the job. */
-			cluster_params.options |= CLUOPT_RECHECK;
-			cluster_rel(rvtc->tableOid, rvtc->indexOid,
-						&cluster_params);
-			PopActiveSnapshot();
-			CommitTransactionCommand();
-		}
+	/* Cluster the tables, each in a separate transaction */
+	foreach(lc, rvs)
+	{
+		RelToCluster *rvtc = (RelToCluster *) lfirst(lc);
 
-		/* Start a new transaction for the cleanup work. */
+		/* Start a new transaction for each relation. */
 		StartTransactionCommand();
 
-		/* Clean up working storage */
-		MemoryContextDelete(cluster_context);
+		/* functions in indexes may want a snapshot set */
+		PushActiveSnapshot(GetTransactionSnapshot());
+
+		/* Do the job. */
+		cluster_rel(rvtc->tableOid, rvtc->indexOid, params);
+
+		PopActiveSnapshot();
+		CommitTransactionCommand();
 	}
 }
 
@@ -327,10 +359,11 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		/*
 		 * Silently skip a temp table for a remote session.  Only doing this
 		 * check in the "recheck" case is appropriate (which currently means
-		 * somebody is executing a database-wide CLUSTER), because there is
-		 * another check in cluster() which will stop any attempt to cluster
-		 * remote temp tables by name.  There is another check in cluster_rel
-		 * which is redundant, but we leave it for extra safety.
+		 * somebody is executing a database-wide CLUSTER or on a partitioned
+		 * table), because there is another check in cluster() which will stop
+		 * any attempt to cluster remote temp tables by name.  There is
+		 * another check in cluster_rel which is redundant, but we leave it
+		 * for extra safety.
 		 */
 		if (RELATION_IS_OTHER_TEMP(OldHeap))
 		{
@@ -352,9 +385,11 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 			}
 
 			/*
-			 * Check that the index is still the one with indisclustered set.
+			 * Check that the index is still the one with indisclustered set,
+			 * if needed.
 			 */
-			if (!get_index_isclustered(indexOid))
+			if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
+				!get_index_isclustered(indexOid))
 			{
 				relation_close(OldHeap, AccessExclusiveLock);
 				pgstat_progress_end_command();
@@ -415,6 +450,9 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 		return;
 	}
 
+	Assert(OldHeap->rd_rel->relkind == RELKIND_RELATION ||
+		   OldHeap->rd_rel->relkind == RELKIND_MATVIEW);
+
 	/*
 	 * All predicate locks on the tuples or pages are about to be made
 	 * invalid, because we move tuples around.  Promote them to relation
@@ -585,8 +623,8 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
 	TransactionId frozenXid;
 	MultiXactId cutoffMulti;
 
-	/* Mark the correct index as clustered */
 	if (OidIsValid(indexOid))
+		/* Mark the correct index as clustered */
 		mark_index_clustered(OldHeap, indexOid, true);
 
 	/* Remember info about rel before closing OldHeap */
@@ -1528,8 +1566,8 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 
 			/*
 			 * Reset the relrewrite for the toast. The command-counter
-			 * increment is required here as we are about to update
-			 * the tuple that is updated as part of RenameRelationInternal.
+			 * increment is required here as we are about to update the tuple
+			 * that is updated as part of RenameRelationInternal.
 			 */
 			CommandCounterIncrement();
 			ResetRelRewrite(newrel->rd_rel->reltoastrelid);
@@ -1564,8 +1602,7 @@ get_tables_to_cluster(MemoryContext cluster_context)
 	HeapTuple	indexTuple;
 	Form_pg_index index;
 	MemoryContext old_context;
-	RelToCluster *rvtc;
-	List	   *rvs = NIL;
+	List	   *rtcs = NIL;
 
 	/*
 	 * Get all indexes that have indisclustered set and are owned by
@@ -1579,21 +1616,20 @@ get_tables_to_cluster(MemoryContext cluster_context)
 	scan = table_beginscan_catalog(indRelation, 1, &entry);
 	while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
 	{
+		RelToCluster *rtc;
+
 		index = (Form_pg_index) GETSTRUCT(indexTuple);
 
 		if (!pg_class_ownercheck(index->indrelid, GetUserId()))
 			continue;
 
-		/*
-		 * We have to build the list in a different memory context so it will
-		 * survive the cross-transaction processing
-		 */
+		/* Use a permanent memory context for the result list */
 		old_context = MemoryContextSwitchTo(cluster_context);
 
-		rvtc = (RelToCluster *) palloc(sizeof(RelToCluster));
-		rvtc->tableOid = index->indrelid;
-		rvtc->indexOid = index->indexrelid;
-		rvs = lappend(rvs, rvtc);
+		rtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rtc->tableOid = index->indrelid;
+		rtc->indexOid = index->indexrelid;
+		rtcs = lappend(rtcs, rtc);
 
 		MemoryContextSwitchTo(old_context);
 	}
@@ -1601,5 +1637,45 @@ get_tables_to_cluster(MemoryContext cluster_context)
 
 	relation_close(indRelation, AccessShareLock);
 
-	return rvs;
+	return rtcs;
+}
+
+/*
+ * Given an index on a partitioned table, return a list of RelToCluster for
+ * all the children leaves tables/indexes.
+ *
+ * Caller must hold lock on the table containing the index.
+ */
+static List *
+get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
+{
+	List	   *inhoids;
+	ListCell   *lc;
+	List	   *rtcs = NIL;
+	MemoryContext old_context;
+
+	/* Do not lock the children until they're processed */
+	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
+
+	/* Use a permanent memory context for the result list */
+	old_context = MemoryContextSwitchTo(cluster_context);
+
+	foreach(lc, inhoids)
+	{
+		Oid			indexrelid = lfirst_oid(lc);
+		Oid			relid = IndexGetRelation(indexrelid, false);
+		RelToCluster *rtc;
+
+		/* consider only leaf indexes */
+		if (get_rel_relkind(indexrelid) != RELKIND_INDEX)
+			continue;
+
+		rtc = (RelToCluster *) palloc(sizeof(RelToCluster));
+		rtc->tableOid = relid;
+		rtc->indexOid = indexrelid;
+		rtcs = lappend(rtcs, rtc);
+	}
+
+	MemoryContextSwitchTo(old_context);
+	return rtcs;
 }
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 51b4a00d50..7febb5018f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -16911,11 +16911,11 @@ AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
 
 /*
  * This is intended as a callback for RangeVarGetRelidExtended().  It allows
- * the relation to be locked only if (1) it's a plain table, materialized
- * view, or TOAST table and (2) the current user is the owner (or the
- * superuser).  This meets the permission-checking needs of CLUSTER, REINDEX
- * TABLE, and REFRESH MATERIALIZED VIEW; we expose it here so that it can be
- * used by all.
+ * the relation to be locked only if (1) it's a plain or partitioned table,
+ * materialized view, or TOAST table and (2) the current user is the owner (or
+ * the superuser).  This meets the permission-checking needs of CLUSTER,
+ * REINDEX TABLE, and REFRESH MATERIALIZED VIEW; we expose it here so that it
+ * can be used by all.
  */
 void
 RangeVarCallbackOwnsTable(const RangeVar *relation,
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 3f9dfffd57..6f040674a2 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -897,6 +897,7 @@ static const SchemaQuery Query_for_list_of_clusterables = {
 	.catname = "pg_catalog.pg_class c",
 	.selcondition =
 	"c.relkind IN (" CppAsString2(RELKIND_RELATION) ", "
+	CppAsString2(RELKIND_PARTITIONED_TABLE) ", "
 	CppAsString2(RELKIND_MATVIEW) ")",
 	.viscondition = "pg_catalog.pg_table_is_visible(c.oid)",
 	.namespace = "c.relnamespace",
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index 3db375d7cc..3c279f6210 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -19,9 +19,11 @@
 #include "utils/relcache.h"
 
 
-/* flag bits for ClusterParams->flags */
-#define CLUOPT_RECHECK 0x01		/* recheck relation state */
-#define CLUOPT_VERBOSE 0x02		/* print progress info */
+/* flag bits for ClusterParams->options */
+#define CLUOPT_VERBOSE 0x01		/* print progress info */
+#define CLUOPT_RECHECK 0x02		/* recheck relation state */
+#define CLUOPT_RECHECK_ISCLUSTERED 0x04 /* recheck relation state for
+										 * indisclustered */
 
 /* options for CLUSTER */
 typedef struct ClusterParams
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index e46a66952f..3f2758d13f 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -444,13 +444,52 @@ DROP TABLE clustertest;
 CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+ERROR:  cannot cluster on invalid index "clstrpart_only_idx"
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+CLUSTER clstrpart USING clstrpart_idx;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+   relname   | level | relkind | ?column? 
+-------------+-------+---------+----------
+ clstrpart   |     0 | p       | t
+ clstrpart1  |     1 | p       | t
+ clstrpart11 |     2 | r       | f
+ clstrpart12 |     2 | p       | t
+ clstrpart2  |     1 | r       | f
+ clstrpart3  |     1 | p       | t
+ clstrpart33 |     2 | r       | f
+(7 rows)
+
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+       Partitioned table "public.clstrpart"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+Partition key: RANGE (a)
+Indexes:
+    "clstrpart_idx" btree (a)
+Number of partitions: 3 (Use \d+ to list them.)
+
+CLUSTER clstrpart;
+ERROR:  there is no previously clustered index for table "clstrpart"
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ERROR:  cannot mark index clustered in partitioned table
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ERROR:  cannot mark index clustered in partitioned table
-CLUSTER clstrpart USING clstrpart_idx;
-ERROR:  cannot cluster a partitioned table
 DROP TABLE clstrpart;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index aee9cf83e0..74118993a8 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -202,11 +202,28 @@ CREATE TABLE clustertest (f1 int PRIMARY KEY);
 CLUSTER clustertest USING clustertest_pkey;
 CLUSTER clustertest;
 
--- Check that partitioned tables cannot be clustered
+-- Check that partitioned tables can be clustered
 CREATE TABLE clstrpart (a int) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart1 PARTITION OF clstrpart FOR VALUES FROM (1)TO(10) PARTITION BY RANGE (a);
+CREATE TABLE clstrpart11 PARTITION OF clstrpart1 FOR VALUES FROM (1)TO(10);
+CREATE TABLE clstrpart12 PARTITION OF clstrpart1 FOR VALUES FROM (10)TO(20) PARTITION BY RANGE(a);
+CREATE TABLE clstrpart2 PARTITION OF clstrpart FOR VALUES FROM (20)TO(30);
+CREATE TABLE clstrpart3 PARTITION OF clstrpart DEFAULT PARTITION BY RANGE(a);
+CREATE TABLE clstrpart33 PARTITION OF clstrpart3 DEFAULT;
+CREATE INDEX clstrpart_only_idx ON ONLY clstrpart (a);
+CLUSTER clstrpart USING clstrpart_only_idx; -- fails
+DROP INDEX clstrpart_only_idx;
 CREATE INDEX clstrpart_idx ON clstrpart (a);
-ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
+-- Check that clustering sets new relfilenodes:
+CREATE TEMP TABLE old_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
 CLUSTER clstrpart USING clstrpart_idx;
+CREATE TEMP TABLE new_cluster_info AS SELECT relname, level, relfilenode, relkind FROM pg_partition_tree('clstrpart'::regclass) AS tree JOIN pg_class c ON c.oid=tree.relid ;
+SELECT relname, old.level, old.relkind, old.relfilenode = new.relfilenode FROM old_cluster_info AS old JOIN new_cluster_info AS new USING (relname) ORDER BY relname COLLATE "C";
+-- Partitioned indexes aren't and can't be marked un/clustered:
+\d clstrpart
+CLUSTER clstrpart;
+ALTER TABLE clstrpart SET WITHOUT CLUSTER;
+ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 DROP TABLE clstrpart;
 
 -- Test CLUSTER with external tuplesorting

From 19c02209dfbcbf73494e1e6d3ca0db50f64dc5fd Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Fri, 24 Sep 2021 14:18:52 -0500
Subject: [PATCH v13 1/2] Recheck arg is not needed since 2011

It was added at: a4dde3bff36dac1ac0b699becad6f103d861a874
And not used since: 7e2f906201c8bb95f7fb17e56b8740c38bda5441
---
 src/backend/commands/cluster.c   | 6 +++---
 src/backend/commands/tablecmds.c | 2 +-
 src/include/commands/cluster.h   | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 322d6bb2f18..0f0a6e9f018 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -232,7 +232,7 @@ cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
 	if (rel != NULL)
 	{
 		Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
-		check_index_is_clusterable(rel, indexOid, true, AccessShareLock);
+		check_index_is_clusterable(rel, indexOid, AccessShareLock);
 		rtcs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
 
 		/* close relation, releasing lock on parent table */
@@ -434,7 +434,7 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 
 	/* Check heap and index are valid to cluster on */
 	if (OidIsValid(indexOid))
-		check_index_is_clusterable(OldHeap, indexOid, recheck, AccessExclusiveLock);
+		check_index_is_clusterable(OldHeap, indexOid, AccessExclusiveLock);
 
 	/*
 	 * Quietly ignore the request if this is a materialized view which has not
@@ -480,7 +480,7 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
  * protection here.
  */
 void
-check_index_is_clusterable(Relation OldHeap, Oid indexOid, bool recheck, LOCKMODE lockmode)
+check_index_is_clusterable(Relation OldHeap, Oid indexOid, LOCKMODE lockmode)
 {
 	Relation	OldIndex;
 
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 90edd0bb97d..1d7db41d172 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -14055,7 +14055,7 @@ ATExecClusterOn(Relation rel, const char *indexName, LOCKMODE lockmode)
 						indexName, RelationGetRelationName(rel))));
 
 	/* Check index is valid to cluster on */
-	check_index_is_clusterable(rel, indexOid, false, lockmode);
+	check_index_is_clusterable(rel, indexOid, lockmode);
 
 	/* And do the work */
 	mark_index_clustered(rel, indexOid, false);
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index 3c279f6210a..df8e73af409 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -34,7 +34,7 @@ typedef struct ClusterParams
 extern void cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel);
 extern void cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params);
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
-									   bool recheck, LOCKMODE lockmode);
+									   LOCKMODE lockmode);
 extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
 
 extern Oid	make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, Oid NewAccessMethod,
-- 
2.17.1

From 4fc03463d51cc55de676813a7a8ac7321ecc7be7 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 6 Apr 2022 07:23:39 -0500
Subject: [PATCH v13 2/2] cluster: early ownership check of partitions

Similar to a556549d7, check the ownership of partitions before queueing them to
be clustered.  Otherwise, we may later wait on an exclusive lock on a partition
only for it to fails ownership check anyway, causing other queries to wait
behind cluster.
---
 src/backend/commands/cluster.c        | 19 +++++++++++++++----
 src/test/regress/expected/cluster.out | 21 +++++++++++++++++++++
 src/test/regress/sql/cluster.sql      | 15 +++++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 0f0a6e9f018..671ea3f45a2 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -1663,9 +1663,6 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
 	/* Do not lock the children until they're processed */
 	inhoids = find_all_inheritors(indexOid, NoLock, NULL);
 
-	/* Use a permanent memory context for the result list */
-	old_context = MemoryContextSwitchTo(cluster_context);
-
 	foreach(lc, inhoids)
 	{
 		Oid			indexrelid = lfirst_oid(lc);
@@ -1676,12 +1673,26 @@ get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
 		if (get_rel_relkind(indexrelid) != RELKIND_INDEX)
 			continue;
 
+		/*
+		 * Silently skip partitions which the user has no access to.  They'll
+		 * be skipped later anyway, but this avoids blocking before the
+		 * permission check if another session is reading the table.
+		 */
+		if (!pg_class_ownercheck(relid, GetUserId()) &&
+				(!pg_database_ownercheck(MyDatabaseId, GetUserId()) ||
+				 IsSharedRelation(relid)))
+			continue;
+
+		/* Use a permanent memory context for the result list */
+		old_context = MemoryContextSwitchTo(cluster_context);
+
 		rtc = (RelToCluster *) palloc(sizeof(RelToCluster));
 		rtc->tableOid = relid;
 		rtc->indexOid = indexrelid;
 		rtcs = lappend(rtcs, rtc);
+
+		MemoryContextSwitchTo(old_context);
 	}
 
-	MemoryContextSwitchTo(old_context);
 	return rtcs;
 }
diff --git a/src/test/regress/expected/cluster.out b/src/test/regress/expected/cluster.out
index 953818c74e1..08e10d89dcf 100644
--- a/src/test/regress/expected/cluster.out
+++ b/src/test/regress/expected/cluster.out
@@ -493,6 +493,27 @@ ERROR:  cannot mark index clustered in partitioned table
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 ERROR:  cannot mark index clustered in partitioned table
 DROP TABLE clstrpart;
+-- Ownership of partitions is checked
+CREATE TABLE ptnowner(i int unique) PARTITION BY LIST (i);
+CREATE INDEX ptnowner_i_idx ON ptnowner(i);
+CREATE TABLE ptnowner1 PARTITION OF ptnowner FOR VALUES IN (1);
+CREATE ROLE ptnowner;
+CREATE TABLE ptnowner2 PARTITION OF ptnowner FOR VALUES IN (2);
+ALTER TABLE ptnowner1 OWNER TO ptnowner;
+ALTER TABLE ptnowner OWNER TO ptnowner;
+SET SESSION AUTHORIZATION ptnowner;
+CREATE TEMP TABLE ptnowner_oldnodes AS SELECT oid, relname, relfilenode FROM pg_partition_tree('ptnowner') AS tree JOIN pg_class AS c ON c.oid=tree.relid;
+CLUSTER ptnowner USING ptnowner_i_idx;
+SELECT a.relname, a.relfilenode=b.relfilenode FROM pg_class a JOIN ptnowner_oldnodes b USING (oid) ORDER BY a.relname COLLATE "C";
+  relname  | ?column? 
+-----------+----------
+ ptnowner  | t
+ ptnowner1 | f
+ ptnowner2 | t
+(3 rows)
+
+RESET SESSION AUTHORIZATION;
+DROP TABLE ptnowner;
 -- Test CLUSTER with external tuplesorting
 create table clstr_4 as select * from tenk1;
 create index cluster_sort on clstr_4 (hundred, thousand, tenthous);
diff --git a/src/test/regress/sql/cluster.sql b/src/test/regress/sql/cluster.sql
index 5601684ee3f..631eec1b739 100644
--- a/src/test/regress/sql/cluster.sql
+++ b/src/test/regress/sql/cluster.sql
@@ -229,6 +229,21 @@ ALTER TABLE clstrpart SET WITHOUT CLUSTER;
 ALTER TABLE clstrpart CLUSTER ON clstrpart_idx;
 DROP TABLE clstrpart;
 
+-- Ownership of partitions is checked
+CREATE TABLE ptnowner(i int unique) PARTITION BY LIST (i);
+CREATE INDEX ptnowner_i_idx ON ptnowner(i);
+CREATE TABLE ptnowner1 PARTITION OF ptnowner FOR VALUES IN (1);
+CREATE ROLE ptnowner;
+CREATE TABLE ptnowner2 PARTITION OF ptnowner FOR VALUES IN (2);
+ALTER TABLE ptnowner1 OWNER TO ptnowner;
+ALTER TABLE ptnowner OWNER TO ptnowner;
+SET SESSION AUTHORIZATION ptnowner;
+CREATE TEMP TABLE ptnowner_oldnodes AS SELECT oid, relname, relfilenode FROM pg_partition_tree('ptnowner') AS tree JOIN pg_class AS c ON c.oid=tree.relid;
+CLUSTER ptnowner USING ptnowner_i_idx;
+SELECT a.relname, a.relfilenode=b.relfilenode FROM pg_class a JOIN ptnowner_oldnodes b USING (oid) ORDER BY a.relname COLLATE "C";
+RESET SESSION AUTHORIZATION;
+DROP TABLE ptnowner;
+
 -- Test CLUSTER with external tuplesorting
 
 create table clstr_4 as select * from tenk1;
-- 
2.17.1

From fdf5347bf4853f19341a8d67a655cae9fece15f0 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Sat, 16 Apr 2022 20:52:03 +0900
Subject: [PATCH] Add isolation tests for CLUSTER with partitions

---
 .../expected/cluster-conflict-partition.out   | 35 ++++++++++++++++++
 .../isolation/expected/cluster-conflict.out   | 19 ++++++++++
 src/test/isolation/isolation_schedule         |  2 +
 .../specs/cluster-conflict-partition.spec     | 37 +++++++++++++++++++
 .../isolation/specs/cluster-conflict.spec     | 30 +++++++++++++++
 5 files changed, 123 insertions(+)
 create mode 100644 src/test/isolation/expected/cluster-conflict-partition.out
 create mode 100644 src/test/isolation/expected/cluster-conflict.out
 create mode 100644 src/test/isolation/specs/cluster-conflict-partition.spec
 create mode 100644 src/test/isolation/specs/cluster-conflict.spec

diff --git a/src/test/isolation/expected/cluster-conflict-partition.out b/src/test/isolation/expected/cluster-conflict-partition.out
new file mode 100644
index 0000000000..7acb675c97
--- /dev/null
+++ b/src/test/isolation/expected/cluster-conflict-partition.out
@@ -0,0 +1,35 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_begin s1_lock_parent s2_auth s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s1_lock_parent: LOCK cluster_part_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_cluster_part;
+step s2_cluster: CLUSTER cluster_part_tab USING cluster_part_ind; <waiting ...>
+step s1_commit: COMMIT;
+step s2_cluster: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s1_lock_parent s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_cluster_part;
+step s1_lock_parent: LOCK cluster_part_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_cluster: CLUSTER cluster_part_tab USING cluster_part_ind; <waiting ...>
+step s1_commit: COMMIT;
+step s2_cluster: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s1_lock_child s2_auth s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s1_lock_child: LOCK cluster_part_tab1 IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_cluster_part;
+step s2_cluster: CLUSTER cluster_part_tab USING cluster_part_ind;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s1_lock_child s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_cluster_part;
+step s1_lock_child: LOCK cluster_part_tab1 IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_cluster: CLUSTER cluster_part_tab USING cluster_part_ind;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
diff --git a/src/test/isolation/expected/cluster-conflict.out b/src/test/isolation/expected/cluster-conflict.out
new file mode 100644
index 0000000000..614d8f9d15
--- /dev/null
+++ b/src/test/isolation/expected/cluster-conflict.out
@@ -0,0 +1,19 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_begin s1_lock s2_auth s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s1_lock: LOCK cluster_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_cluster_conflict;
+step s2_cluster: CLUSTER cluster_tab USING cluster_ind; <waiting ...>
+step s1_commit: COMMIT;
+step s2_cluster: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s1_lock s2_cluster s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_cluster_conflict;
+step s1_lock: LOCK cluster_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_cluster: CLUSTER cluster_tab USING cluster_ind; <waiting ...>
+step s1_commit: COMMIT;
+step s2_cluster: <... completed>
+step s2_reset: RESET ROLE;
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index 607760386e..529a4cbd4d 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -102,6 +102,8 @@ test: partition-key-update-2
 test: partition-key-update-3
 test: partition-key-update-4
 test: plpgsql-toast
+test: cluster-conflict
+test: cluster-conflict-partition
 test: truncate-conflict
 test: serializable-parallel
 test: serializable-parallel-2
diff --git a/src/test/isolation/specs/cluster-conflict-partition.spec b/src/test/isolation/specs/cluster-conflict-partition.spec
new file mode 100644
index 0000000000..5091f684a9
--- /dev/null
+++ b/src/test/isolation/specs/cluster-conflict-partition.spec
@@ -0,0 +1,37 @@
+# Tests for locking conflicts with CLUSTER command and partitions.
+
+setup
+{
+	CREATE ROLE regress_cluster_part;
+	CREATE TABLE cluster_part_tab (a int) PARTITION BY LIST (a);
+	CREATE TABLE cluster_part_tab1 PARTITION OF cluster_part_tab FOR VALUES IN (1);
+	CREATE TABLE cluster_part_tab2 PARTITION OF cluster_part_tab FOR VALUES IN (2);
+	CREATE INDEX cluster_part_ind ON cluster_part_tab(a);
+	ALTER TABLE cluster_part_tab OWNER TO regress_cluster_part;
+}
+
+teardown
+{
+	DROP TABLE cluster_part_tab;
+	DROP ROLE regress_cluster_part;
+}
+
+session s1
+step s1_begin          { BEGIN; }
+step s1_lock_parent    { LOCK cluster_part_tab IN SHARE UPDATE EXCLUSIVE MODE; }
+step s1_lock_child     { LOCK cluster_part_tab1 IN SHARE UPDATE EXCLUSIVE MODE; }
+step s1_commit         { COMMIT; }
+
+session s2
+step s2_auth           { SET ROLE regress_cluster_part; }
+step s2_cluster        { CLUSTER cluster_part_tab USING cluster_part_ind; }
+step s2_reset          { RESET ROLE; }
+
+# CLUSTER on the parent waits if locked, passes for all cases.
+permutation s1_begin s1_lock_parent s2_auth s2_cluster s1_commit s2_reset
+permutation s1_begin s2_auth s1_lock_parent s2_cluster s1_commit s2_reset
+
+# When taking a lock on a partition leaf, CLUSTER on the parent skips
+# the leaf, passes for all cases.
+permutation s1_begin s1_lock_child s2_auth s2_cluster s1_commit s2_reset
+permutation s1_begin s2_auth s1_lock_child s2_cluster s1_commit s2_reset
diff --git a/src/test/isolation/specs/cluster-conflict.spec b/src/test/isolation/specs/cluster-conflict.spec
new file mode 100644
index 0000000000..2e1d547f01
--- /dev/null
+++ b/src/test/isolation/specs/cluster-conflict.spec
@@ -0,0 +1,30 @@
+# Tests for locking conflicts with CLUSTER command.
+
+setup
+{
+	CREATE ROLE regress_cluster_conflict;
+	CREATE TABLE cluster_tab (a int);
+	CREATE INDEX cluster_ind ON cluster_tab(a);
+	ALTER TABLE cluster_tab OWNER TO regress_cluster_conflict;
+}
+
+teardown
+{
+	DROP TABLE cluster_tab;
+	DROP ROLE regress_cluster_conflict;
+}
+
+session s1
+step s1_begin          { BEGIN; }
+step s1_lock           { LOCK cluster_tab IN SHARE UPDATE EXCLUSIVE MODE; }
+step s1_commit         { COMMIT; }
+
+session s2
+step s2_auth           { SET ROLE regress_cluster_conflict; }
+step s2_cluster        { CLUSTER cluster_tab USING cluster_ind; }
+step s2_reset          { RESET ROLE; }
+
+# The role has privileges to cluster the table, CLUSTER will block if
+# another session holds a lock on the table and succeed in all cases.
+permutation s1_begin s1_lock s2_auth s2_cluster s1_commit s2_reset
+permutation s1_begin s2_auth s1_lock s2_cluster s1_commit s2_reset
-- 
2.35.2