Don't reset relhasindex for partitioned tables on ANALYZE

Commit 0e69f70 introduced code to analyze partitioned table;
however, that code fails to preserve pg_class.relhasindex correctly.
Fix by observing whether any indexes exist rather than accidentally
falling through to assuming none do.

Backpatch to 14.

Author: Alexander Pyhalov <a.pyhalov@postgrespro.ru>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CALNJ-vS1R3Qoe5t4tbzxrkpBtzRbPq1dDcW4RmA_a+oqweF30w@mail.gmail.com

Author: alvherre

src/backend/commands/analyze.c

@@ -420,20 +420,34 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 	/*
 	 * Open all indexes of the relation, and see if there are any analyzable
 	 * columns in the indexes.  We do not analyze index columns if there was
-	 * an explicit column list in the ANALYZE command, however.  If we are
-	 * doing a recursive scan, we don't want to touch the parent's indexes at
-	 * all.
+	 * an explicit column list in the ANALYZE command, however.
+	 *
+	 * If we are doing a recursive scan, we don't want to touch the parent's
+	 * indexes at all.  If we're processing a partitioned table, we need to
+	 * know if there are any indexes, but we don't want to process them.
 	 */
-	if (!inh)
+	if (onerel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		List *idxs = RelationGetIndexList(onerel);
+
+		Irel = NULL;
+		nindexes = 0;
+		hasindex = idxs != NIL;
+		list_free(idxs);
+	}
+	else if (!inh)
+	{
 		vac_open_indexes(onerel, AccessShareLock, &nindexes, &Irel);
+		hasindex = nindexes > 0;
+	}
 	else
 	{
 		Irel = NULL;
 		nindexes = 0;
+		hasindex = false;
 	}
-	hasindex = (nindexes > 0);
 	indexdata = NULL;
-	if (hasindex)
+	if (nindexes > 0)
 	{
 		indexdata = (AnlIndexData *) palloc0(nindexes * sizeof(AnlIndexData));
 		for (ind = 0; ind < nindexes; ind++)
@@ -572,7 +586,7 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 			MemoryContextResetAndDeleteChildren(col_context);
 		}
 
-		if (hasindex)
+		if (nindexes > 0)
 			compute_index_stats(onerel, totalrows,
 								indexdata, nindexes,
 								rows, numrows,
@@ -660,10 +674,10 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 		/*
 		 * Partitioned tables don't have storage, so we don't set any fields
 		 * in their pg_class entries except for reltuples, which is necessary
-		 * for auto-analyze to work properly.
+		 * for auto-analyze to work properly, and relhasindex.
 		 */
 		vac_update_relstats(onerel, -1, totalrows,
-							0, false, InvalidTransactionId,
+							0, hasindex, InvalidTransactionId,
 							InvalidMultiXactId,
 							in_outer_xact);
 	}

src/test/regress/expected/vacuum.out

@@ -199,6 +199,28 @@ VACUUM ANALYZE vacparted(a,b,a);
 ERROR:  column "a" of relation "vacparted" appears more than once
 ANALYZE vacparted(a,b,b);
 ERROR:  column "b" of relation "vacparted" appears more than once
+-- partitioned table with index
+CREATE TABLE vacparted_i (a int primary key, b varchar(100))
+  PARTITION BY HASH (a);
+CREATE TABLE vacparted_i1 PARTITION OF vacparted_i
+  FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE vacparted_i2 PARTITION OF vacparted_i
+  FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO vacparted_i SELECT i, 'test_'|| i from generate_series(1,10) i;
+VACUUM (ANALYZE) vacparted_i;
+VACUUM (FULL) vacparted_i;
+VACUUM (FREEZE) vacparted_i;
+SELECT relname, relhasindex FROM pg_class
+  WHERE relname LIKE 'vacparted_i%' AND relkind IN ('p','r')
+  ORDER BY relname;
+   relname    | relhasindex 
+--------------+-------------
+ vacparted_i  | t
+ vacparted_i1 | t
+ vacparted_i2 | t
+(3 rows)
+
+DROP TABLE vacparted_i;
 -- multiple tables specified
 VACUUM vaccluster, vactst;
 VACUUM vacparted, does_not_exist;

src/test/regress/sql/vacuum.sql

@@ -170,6 +170,22 @@ VACUUM (FREEZE) vacparted;
 VACUUM ANALYZE vacparted(a,b,a);
 ANALYZE vacparted(a,b,b);
 
+-- partitioned table with index
+CREATE TABLE vacparted_i (a int primary key, b varchar(100))
+  PARTITION BY HASH (a);
+CREATE TABLE vacparted_i1 PARTITION OF vacparted_i
+  FOR VALUES WITH (MODULUS 2, REMAINDER 0);
+CREATE TABLE vacparted_i2 PARTITION OF vacparted_i
+  FOR VALUES WITH (MODULUS 2, REMAINDER 1);
+INSERT INTO vacparted_i SELECT i, 'test_'|| i from generate_series(1,10) i;
+VACUUM (ANALYZE) vacparted_i;
+VACUUM (FULL) vacparted_i;
+VACUUM (FREEZE) vacparted_i;
+SELECT relname, relhasindex FROM pg_class
+  WHERE relname LIKE 'vacparted_i%' AND relkind IN ('p','r')
+  ORDER BY relname;
+DROP TABLE vacparted_i;
+
 -- multiple tables specified
 VACUUM vaccluster, vactst;
 VACUUM vacparted, does_not_exist;