[#26639] YSQL: Add support for matview indexes to index consistency checker

Summary:
This revision adds support to check the consistency of materialized view indexes via `yb_index_check()`. This involved creating dummy index objects (`rd_index`, `rd_indam`, and `rd_opfamily`) for materialized view relations during the index check and freeing these at the end.

In the passing, also cleanup redundant commands to set/unset `yb_non_ddl_txn_for_sys_tables_allowed` in yb_index_check test.

Jira: DB-16013

Test Plan:
   ./yb_build.sh --java-test 'org.yb.pgsql.TestPgRegressYbIndexCheck'

Close: #26639

Reviewers: amartsinchyk, stiwary, #db-approvers

Reviewed By: stiwary

Subscribers: svc_phabricator, yql

Differential Revision: https://phorge.dev.yugabyte.com/D42954

Author: arpang

src/postgres/src/backend/access/index/indexam.c

@@ -140,7 +140,8 @@ yb_dummy_baserel_index_open(Oid relationId, LOCKMODE lockmode)
 
 	relation = relation_open(relationId, lockmode);
 
-	if (relation->rd_rel->relkind == RELKIND_RELATION)
+	if (relation->rd_rel->relkind == RELKIND_RELATION ||
+		relation->rd_rel->relkind == RELKIND_MATVIEW)
 	{
 		Assert(!relation->rd_index);
 		Assert(!relation->rd_indam);
@@ -179,6 +180,10 @@ yb_dummy_baserel_index_open(Oid relationId, LOCKMODE lockmode)
 void
 yb_free_dummy_baserel_index(Relation relation)
 {
+	if (!(relation->rd_rel->relkind == RELKIND_RELATION ||
+		  relation->rd_rel->relkind == RELKIND_MATVIEW))
+		return;
+
 	Assert(relation->rd_index);
 	Assert(relation->rd_indam);
 	Assert(relation->rd_opfamily);

src/postgres/src/backend/executor/nodeIndexscan.c

@@ -929,9 +929,9 @@ ExecEndIndexScan(IndexScanState *node)
 		index_endscan(indexScanDesc);
 	if (indexRelationDesc)
 	{
-		if (node->ss.ps.state->yb_exec_params.yb_index_check &&
-			indexRelationDesc->rd_rel->relkind == RELKIND_RELATION)
+		if (node->ss.ps.state->yb_exec_params.yb_index_check)
 			yb_free_dummy_baserel_index(indexRelationDesc);
+
 		index_close(indexRelationDesc, NoLock);
 	}
 }

src/postgres/src/test/regress/expected/yb.orig.yb_index_check.out

@@ -129,7 +129,6 @@ BEGIN
 END;
 $$;
 $force_cache_refresh$ AS force_cache_refresh \gset
-SET yb_non_ddl_txn_for_sys_tables_allowed = TRUE;
 -- Missing Index Row
 UPDATE pg_index SET indisready = FALSE, indisvalid = FALSE, indislive = FALSE WHERE indexrelid = 'abcd_b_c_d_idx'::regclass;
 :force_cache_refresh
@@ -227,7 +226,6 @@ SELECT yb_index_check('abcd_b_c_idx'::regclass::oid);
 
 (1 row)
 
-SET yb_non_ddl_txn_for_sys_tables_allowed = FALSE;
 -- Index of a partitioned table
 CREATE TABLE part(a int, b int, c int, d int) PARTITION BY RANGE(a);
 CREATE INDEX ON part(b) include (c, d);
@@ -266,6 +264,23 @@ SELECT yb_index_check('part_4k_6k_b_c_d_idx'::regclass::oid);
 
 (1 row)
 
+-- Index of materialized view
+CREATE MATERIALIZED VIEW matview AS SELECT * FROM abcd;
+CREATE INDEX matview_b_idx ON matview (b);
+SELECT yb_index_check('matview_b_idx'::regclass);
+ yb_index_check 
+----------------
+ 
+(1 row)
+
+-- Execute the same command second time to check if the dummy index fields are free'd up.
+-- See yb_dummy_baserel_index_open()/yb_free_dummy_baserel_index().
+SELECT yb_index_check('matview_b_idx'::regclass);
+ yb_index_check 
+----------------
+ 
+(1 row)
+
 -- Index of a colocated relation
 CREATE DATABASE colocateddb COLOCATION = TRUE;
 \c colocateddb

src/postgres/src/test/regress/sql/yb.orig.yb_index_check.sql

@@ -86,9 +86,6 @@ END;
 $$;
 $force_cache_refresh$ AS force_cache_refresh \gset
 
-
-SET yb_non_ddl_txn_for_sys_tables_allowed = TRUE;
-
 -- Missing Index Row
 UPDATE pg_index SET indisready = FALSE, indisvalid = FALSE, indislive = FALSE WHERE indexrelid = 'abcd_b_c_d_idx'::regclass;
 :force_cache_refresh
@@ -155,7 +152,6 @@ SELECT yb_index_check('abcd_b_c_idx'::regclass::oid);
 
 UPDATE abcd SET d = 51 WHERE a = 51;
 SELECT yb_index_check('abcd_b_c_idx'::regclass::oid);
-SET yb_non_ddl_txn_for_sys_tables_allowed = FALSE;
 
 -- Index of a partitioned table
 CREATE TABLE part(a int, b int, c int, d int) PARTITION BY RANGE(a);
@@ -172,6 +168,14 @@ SELECT yb_index_check('part_2_b_c_d_idx'::regclass::oid);
 SELECT yb_index_check('part_2k_4k_b_c_d_idx'::regclass::oid);
 SELECT yb_index_check('part_4k_6k_b_c_d_idx'::regclass::oid);
 
+-- Index of materialized view
+CREATE MATERIALIZED VIEW matview AS SELECT * FROM abcd;
+CREATE INDEX matview_b_idx ON matview (b);
+SELECT yb_index_check('matview_b_idx'::regclass);
+-- Execute the same command second time to check if the dummy index fields are free'd up.
+-- See yb_dummy_baserel_index_open()/yb_free_dummy_baserel_index().
+SELECT yb_index_check('matview_b_idx'::regclass);
+
 -- Index of a colocated relation
 CREATE DATABASE colocateddb COLOCATION = TRUE;
 \c colocateddb