Refactor code to look up local replication tuple

This unifies some duplicate code.

Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://www.postgresql.org/message-id/CA+HiwqFjYE5anArxvkjr37AQMd52L-LZtz9Ld2QrLQ3YfcYhTw@mail.gmail.com

src/backend/replication/logical/worker.c

@@ -122,6 +122,10 @@ static void apply_handle_update_internal(ResultRelInfo *relinfo,
 static void apply_handle_delete_internal(ResultRelInfo *relinfo, EState *estate,
 										 TupleTableSlot *remoteslot,
 										 LogicalRepRelation *remoterel);
+static bool FindReplTupleInLocalRel(EState *estate, Relation localrel,
+									LogicalRepRelation *remoterel,
+									TupleTableSlot *remoteslot,
+									TupleTableSlot **localslot);
 
 /*
  * Should this worker apply changes for given relation.
@@ -788,33 +792,17 @@ apply_handle_update_internal(ResultRelInfo *relinfo,
 							 LogicalRepRelMapEntry *relmapentry)
 {
 	Relation	localrel = relinfo->ri_RelationDesc;
-	Oid			idxoid;
 	EPQState	epqstate;
 	TupleTableSlot *localslot;
 	bool		found;
 	MemoryContext oldctx;
 
-	localslot = table_slot_create(localrel, &estate->es_tupleTable);
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1);
-
 	ExecOpenIndices(relinfo, false);
 
-	/*
-	 * Try to find tuple using either replica identity index, primary key or
-	 * if needed, sequential scan.
-	 */
-	idxoid = GetRelationIdentityOrPK(localrel);
-	Assert(OidIsValid(idxoid) ||
-		   (relmapentry->remoterel.replident == REPLICA_IDENTITY_FULL));
-
-	if (OidIsValid(idxoid))
-		found = RelationFindReplTupleByIndex(localrel, idxoid,
-											 LockTupleExclusive,
-											 remoteslot, localslot);
-	else
-		found = RelationFindReplTupleSeq(localrel, LockTupleExclusive,
-										 remoteslot, localslot);
-
+	found = FindReplTupleInLocalRel(estate, localrel,
+									&relmapentry->remoterel,
+									remoteslot, &localslot);
 	ExecClearTuple(remoteslot);
 
 	/*
@@ -922,31 +910,15 @@ apply_handle_delete_internal(ResultRelInfo *relinfo, EState *estate,
 							 LogicalRepRelation *remoterel)
 {
 	Relation	localrel = relinfo->ri_RelationDesc;
-	Oid			idxoid;
 	EPQState	epqstate;
 	TupleTableSlot *localslot;
 	bool		found;
 
-	localslot = table_slot_create(localrel, &estate->es_tupleTable);
 	EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1);
-
 	ExecOpenIndices(relinfo, false);
 
-	/*
-	 * Try to find tuple using either replica identity index, primary key or
-	 * if needed, sequential scan.
-	 */
-	idxoid = GetRelationIdentityOrPK(localrel);
-	Assert(OidIsValid(idxoid) ||
-		   (remoterel->replident == REPLICA_IDENTITY_FULL));
-
-	if (OidIsValid(idxoid))
-		found = RelationFindReplTupleByIndex(localrel, idxoid,
-											 LockTupleExclusive,
-											 remoteslot, localslot);
-	else
-		found = RelationFindReplTupleSeq(localrel, LockTupleExclusive,
-										 remoteslot, localslot);
+	found = FindReplTupleInLocalRel(estate, localrel, remoterel,
+									remoteslot, &localslot);
 
 	/* If found delete it. */
 	if (found)
@@ -970,6 +942,39 @@ apply_handle_delete_internal(ResultRelInfo *relinfo, EState *estate,
 	EvalPlanQualEnd(&epqstate);
 }
 
+/*
+ * Try to find a tuple received from the publication side (in 'remoteslot') in
+ * the corresponding local relation using either replica identity index,
+ * primary key or if needed, sequential scan.
+ *
+ * Local tuple, if found, is returned in '*localslot'.
+ */
+static bool
+FindReplTupleInLocalRel(EState *estate, Relation localrel,
+						LogicalRepRelation *remoterel,
+						TupleTableSlot *remoteslot,
+						TupleTableSlot **localslot)
+{
+	Oid			idxoid;
+	bool		found;
+
+	*localslot = table_slot_create(localrel, &estate->es_tupleTable);
+
+	idxoid = GetRelationIdentityOrPK(localrel);
+	Assert(OidIsValid(idxoid) ||
+		   (remoterel->replident == REPLICA_IDENTITY_FULL));
+
+	if (OidIsValid(idxoid))
+		found = RelationFindReplTupleByIndex(localrel, idxoid,
+											 LockTupleExclusive,
+											 remoteslot, *localslot);
+	else
+		found = RelationFindReplTupleSeq(localrel, LockTupleExclusive,
+										 remoteslot, *localslot);
+
+	return found;
+}
+
 /*
  * Handle TRUNCATE message.
  *