Remove unnecessary checks for indexes for REPLICA IDENTITY FULL tables.

Previously, when selecting an usable index for update/delete for the
REPLICA IDENTITY FULL table, in IsIndexOnlyExpression(), we used to
check if all index fields are not expressions. However, it was not
necessary, because it is enough to check if only the leftmost index
field is not an expression (and references the remote table column)
and this check has already been done by
RemoteRelContainsLeftMostColumnOnIdx().

This commit removes IsIndexOnlyExpression() and
RemoteRelContainsLeftMostColumnOnIdx() and all checks for usable
indexes for REPLICA IDENTITY FULL tables are now performed by
IsIndexUsableForReplicaIdentityFull().

Backpatch this to remain the code consistent.

Reported-by: Peter Smith
Reviewed-by: Amit Kapila, Önder Kalacı
Discussion: https://postgr.es/m/CAHut%2BPsGRE5WSsY0jcLHJEoA17MrbP9yy8FxdjC_ZOAACxbt%2BQ%40mail.gmail.com
Backpatch-through: 16

1 files changed, 19 insertions, 5 deletions

diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index cb6659fc619..832b1cf7642 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -140,6 +140,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "access/genam.h"
 #include "access/table.h"
 #include "access/tableam.h"
 #include "access/twophase.h"
@@ -410,7 +411,7 @@ static void apply_handle_delete_internal(ApplyExecutionData *edata,
 										 ResultRelInfo *relinfo,
 										 TupleTableSlot *remoteslot,
 										 Oid localindexoid);
-static bool FindReplTupleInLocalRel(EState *estate, Relation localrel,
+static bool FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel,
 									LogicalRepRelation *remoterel,
 									Oid localidxoid,
 									TupleTableSlot *remoteslot,
@@ -2663,7 +2664,7 @@ apply_handle_update_internal(ApplyExecutionData *edata,
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL);
 	ExecOpenIndices(relinfo, false);
 
-	found = FindReplTupleInLocalRel(estate, localrel,
+	found = FindReplTupleInLocalRel(edata, localrel,
 									&relmapentry->remoterel,
 									localindexoid,
 									remoteslot, &localslot);
@@ -2816,7 +2817,7 @@ apply_handle_delete_internal(ApplyExecutionData *edata,
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL);
 	ExecOpenIndices(relinfo, false);
 
-	found = FindReplTupleInLocalRel(estate, localrel, remoterel, localindexoid,
+	found = FindReplTupleInLocalRel(edata, localrel, remoterel, localindexoid,
 									remoteslot, &localslot);
 
 	/* If found delete it. */
@@ -2855,12 +2856,13 @@ apply_handle_delete_internal(ApplyExecutionData *edata,
  * Local tuple, if found, is returned in '*localslot'.
  */
 static bool
-FindReplTupleInLocalRel(EState *estate, Relation localrel,
+FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel,
 						LogicalRepRelation *remoterel,
 						Oid localidxoid,
 						TupleTableSlot *remoteslot,
 						TupleTableSlot **localslot)
 {
+	EState	   *estate = edata->estate;
 	bool		found;
 
 	/*
@@ -2875,9 +2877,21 @@ FindReplTupleInLocalRel(EState *estate, Relation localrel,
 		   (remoterel->replident == REPLICA_IDENTITY_FULL));
 
 	if (OidIsValid(localidxoid))
+	{
+#ifdef USE_ASSERT_CHECKING
+		Relation	idxrel = index_open(localidxoid, AccessShareLock);
+
+		/* Index must be PK, RI, or usable for REPLICA IDENTITY FULL tables */
+		Assert(GetRelationIdentityOrPK(idxrel) == localidxoid ||
+			   IsIndexUsableForReplicaIdentityFull(BuildIndexInfo(idxrel),
+												   edata->targetRel->attrmap));
+		index_close(idxrel, AccessShareLock);
+#endif
+
 		found = RelationFindReplTupleByIndex(localrel, localidxoid,
 											 LockTupleExclusive,
 											 remoteslot, *localslot);
+	}
 	else
 		found = RelationFindReplTupleSeq(localrel, LockTupleExclusive,
 										 remoteslot, *localslot);
@@ -2995,7 +3009,7 @@ apply_handle_tuple_routing(ApplyExecutionData *edata,
 				bool		found;
 
 				/* Get the matching local tuple from the partition. */
-				found = FindReplTupleInLocalRel(estate, partrel,
+				found = FindReplTupleInLocalRel(edata, partrel,
 												&part_entry->remoterel,
 												part_entry->localindexoid,
 												remoteslot_part, &localslot);