Lock table in ShareUpdateExclusive when importing index stats.

Follow locking behavior of ANALYZE when importing statistics. In
particular, when importing index statistics, the table must be locked
in ShareUpdateExclusive mode. Fixes bug reportd by Jian He.

ANALYZE doesn't update statistics on partitioned indexes, and the
locking requirements are slightly different for in-place updates on
partitioned indexes versus normal indexes. To be conservative, lock
both the partitioned table and the partitioned index in
ShareUpdateExclusive mode when importing stats for a partitioned
index.

Author: Corey Huinker
Reported-by: Jian He
Reviewed-by: Michael Paquier
Discussion: https://www.postgresql.org/message-id/CACJufxGreTY7qsCV8%2BBkuv0p5SXGTScgh%3DD%2BDq6%3D%2B_%3DXTp7FWg%40mail.gmail.com

1 files changed, 57 insertions, 13 deletions

diff --git a/src/backend/statistics/stat_utils.c b/src/backend/statistics/stat_utils.c
index 0d446f55b01..e70ea1ce738 100644
--- a/src/backend/statistics/stat_utils.c
+++ b/src/backend/statistics/stat_utils.c
@@ -17,13 +17,16 @@
 #include "postgres.h"
 
 #include "access/relation.h"
+#include "catalog/index.h"
 #include "catalog/pg_database.h"
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "statistics/stat_utils.h"
+#include "storage/lmgr.h"
 #include "utils/acl.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
+#include "utils/lsyscache.h"
 #include "utils/rel.h"
 
 /*
@@ -126,45 +129,86 @@ stats_check_arg_pair(FunctionCallInfo fcinfo,
 void
 stats_lock_check_privileges(Oid reloid)
 {
-	Relation	rel = relation_open(reloid, ShareUpdateExclusiveLock);
-	const char	relkind = rel->rd_rel->relkind;
+	Relation	table;
+	Oid			table_oid = reloid;
+	Oid			index_oid = InvalidOid;
+	LOCKMODE	index_lockmode = NoLock;
 
-	/* All of the types that can be used with ANALYZE, plus indexes */
-	switch (relkind)
+	/*
+	 * For indexes, we follow the locking behavior in do_analyze_rel() and
+	 * check_inplace_rel_lock(), which is to lock the table first in
+	 * ShareUpdateExclusive mode and then the index in AccessShare mode.
+	 *
+	 * Partitioned indexes are treated differently than normal indexes in
+	 * check_inplace_rel_lock(), so we take a ShareUpdateExclusive lock on
+	 * both the partitioned table and the partitioned index.
+	 */
+	switch (get_rel_relkind(reloid))
 	{
-		case RELKIND_RELATION:
 		case RELKIND_INDEX:
+			index_oid = reloid;
+			table_oid = IndexGetRelation(index_oid, false);
+			index_lockmode = AccessShareLock;
+			break;
+		case RELKIND_PARTITIONED_INDEX:
+			index_oid = reloid;
+			table_oid = IndexGetRelation(index_oid, false);
+			index_lockmode = ShareUpdateExclusiveLock;
+			break;
+		default:
+			break;
+	}
+
+	table = relation_open(table_oid, ShareUpdateExclusiveLock);
+
+	/* the relkinds that can be used with ANALYZE */
+	switch (table->rd_rel->relkind)
+	{
+		case RELKIND_RELATION:
 		case RELKIND_MATVIEW:
 		case RELKIND_FOREIGN_TABLE:
 		case RELKIND_PARTITIONED_TABLE:
-		case RELKIND_PARTITIONED_INDEX:
 			break;
 		default:
 			ereport(ERROR,
 					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 					 errmsg("cannot modify statistics for relation \"%s\"",
-							RelationGetRelationName(rel)),
-					 errdetail_relkind_not_supported(rel->rd_rel->relkind)));
+							RelationGetRelationName(table)),
+					 errdetail_relkind_not_supported(table->rd_rel->relkind)));
+	}
+
+	if (OidIsValid(index_oid))
+	{
+		Relation	index;
+
+		Assert(index_lockmode != NoLock);
+		index = relation_open(index_oid, index_lockmode);
+
+		Assert(index->rd_index && index->rd_index->indrelid == table_oid);
+
+		/* retain lock on index */
+		relation_close(index, NoLock);
 	}
 
-	if (rel->rd_rel->relisshared)
+	if (table->rd_rel->relisshared)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("cannot modify statistics for shared relation")));
 
 	if (!object_ownercheck(DatabaseRelationId, MyDatabaseId, GetUserId()))
 	{
-		AclResult	aclresult = pg_class_aclcheck(RelationGetRelid(rel),
+		AclResult	aclresult = pg_class_aclcheck(RelationGetRelid(table),
 												  GetUserId(),
 												  ACL_MAINTAIN);
 
 		if (aclresult != ACLCHECK_OK)
 			aclcheck_error(aclresult,
-						   get_relkind_objtype(rel->rd_rel->relkind),
-						   NameStr(rel->rd_rel->relname));
+						   get_relkind_objtype(table->rd_rel->relkind),
+						   NameStr(table->rd_rel->relname));
 	}
 
-	relation_close(rel, NoLock);
+	/* retain lock on table */
+	relation_close(table, NoLock);
 }
 
 /*