From 549ca4de6d9f4136f2a0104c11121b46b2fb1aae Mon Sep 17 00:00:00 2001
From: Onur Tirtir <onurcantirtir@gmail.com>
Date: Wed, 18 Aug 2021 01:09:12 +0300
Subject: [PATCH] Use RelationGetIndexList instead of scanning pg_index

---
 src/backend/distributed/commands/index.c      | 40 +++++++------------
 .../distributed/operations/node_protocol.c    |  6 +++
 2 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/src/backend/distributed/commands/index.c b/src/backend/distributed/commands/index.c
index 6a0e39739..bd1b9eb88 100644
--- a/src/backend/distributed/commands/index.c
+++ b/src/backend/distributed/commands/index.c
@@ -306,37 +306,25 @@ ExecuteFunctionOnEachTableIndex(Oid relationId, PGIndexProcessor pgIndexProcesso
 								int indexFlags)
 {
 	List *result = NIL;
-	ScanKeyData scanKey[1];
-	int scanKeyCount = 1;
 
-	PushOverrideEmptySearchPath(CurrentMemoryContext);
-
-	/* open system catalog and scan all indexes that belong to this table */
-	Relation pgIndex = table_open(IndexRelationId, AccessShareLock);
-
-	ScanKeyInit(&scanKey[0], Anum_pg_index_indrelid,
-				BTEqualStrategyNumber, F_OIDEQ, relationId);
-
-	SysScanDesc scanDescriptor = systable_beginscan(pgIndex,
-													IndexIndrelidIndexId, true, /* indexOK */
-													NULL, scanKeyCount, scanKey);
-
-	HeapTuple heapTuple = systable_getnext(scanDescriptor);
-	while (HeapTupleIsValid(heapTuple))
+	Relation relation = RelationIdGetRelation(relationId);
+	List *indexIdList = RelationGetIndexList(relation);
+	Oid indexId = InvalidOid;
+	foreach_oid(indexId, indexIdList)
 	{
-		Form_pg_index indexForm = (Form_pg_index) GETSTRUCT(heapTuple);
-		pgIndexProcessor(indexForm, &result, indexFlags);
+		HeapTuple indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexId));
+		if (!HeapTupleIsValid(indexTuple))
+		{
+			ereport(ERROR, (errmsg("cache lookup failed for index with oid %u",
+								   indexId)));
+		}
 
-		heapTuple = systable_getnext(scanDescriptor);
+		Form_pg_index indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
+		pgIndexProcessor(indexForm, &result, indexFlags);
+		ReleaseSysCache(indexTuple);
 	}
 
-	/* clean up scan and close system catalog */
-	systable_endscan(scanDescriptor);
-	table_close(pgIndex, AccessShareLock);
-
-	/* revert back to original search_path */
-	PopOverrideSearchPath();
-
+	RelationClose(relation);
 	return result;
 }
 
diff --git a/src/backend/distributed/operations/node_protocol.c b/src/backend/distributed/operations/node_protocol.c
index f0ff1c82b..1638489e7 100644
--- a/src/backend/distributed/operations/node_protocol.c
+++ b/src/backend/distributed/operations/node_protocol.c
@@ -798,6 +798,9 @@ void
 GatherIndexAndConstraintDefinitionList(Form_pg_index indexForm, List **indexDDLEventList,
 									   int indexFlags)
 {
+	/* generate fully-qualified names */
+	PushOverrideEmptySearchPath(CurrentMemoryContext);
+
 	Oid indexId = indexForm->indexrelid;
 	bool indexImpliedByConstraint = IndexImpliedByAConstraint(indexForm);
 
@@ -845,6 +848,9 @@ GatherIndexAndConstraintDefinitionList(Form_pg_index indexForm, List **indexDDLE
 		*indexDDLEventList = list_concat(*indexDDLEventList,
 										 alterIndexStatisticsCommands);
 	}
+
+	/* revert back to original search_path */
+	PopOverrideSearchPath();
 }