Fix the warnings introduced in commit ce0fdbfe97.

Author: Amit Kapila
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/1610789.1613170207@sss.pgh.pa.us

src/backend/commands/subscriptioncmds.c

@@ -715,7 +715,8 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data)
 					 * the origin might be already removed. For these reasons,
 					 * passing missing_ok = true.
 					 */
-					ReplicationOriginNameForTablesync(sub->oid, relid, originname);
+					ReplicationOriginNameForTablesync(sub->oid, relid, originname,
+													  sizeof(originname));
 					replorigin_drop_by_name(originname, true, false);
 				}
 
@@ -749,7 +750,8 @@ AlterSubscription_refresh(Subscription *sub, bool copy_data)
 				 * dropped slots and fail. For these reasons, we allow
 				 * missing_ok = true for the drop.
 				 */
-				ReplicationSlotNameForTablesync(sub->oid, sub_remove_rels[off].relid, syncslotname);
+				ReplicationSlotNameForTablesync(sub->oid, sub_remove_rels[off].relid,
+												syncslotname, sizeof(syncslotname));
 				ReplicationSlotDropAtPubNode(wrconn, syncslotname, true);
 			}
 		}
@@ -1174,7 +1176,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 		 * worker so passing missing_ok = true. This can happen for the states
 		 * before SUBREL_STATE_FINISHEDCOPY.
 		 */
-		ReplicationOriginNameForTablesync(subid, relid, originname);
+		ReplicationOriginNameForTablesync(subid, relid, originname,
+										  sizeof(originname));
 		replorigin_drop_by_name(originname, true, false);
 	}
 
@@ -1254,7 +1257,8 @@ DropSubscription(DropSubscriptionStmt *stmt, bool isTopLevel)
 			{
 				char		syncslotname[NAMEDATALEN] = {0};
 
-				ReplicationSlotNameForTablesync(subid, relid, syncslotname);
+				ReplicationSlotNameForTablesync(subid, relid, syncslotname,
+												sizeof(syncslotname));
 				ReplicationSlotDropAtPubNode(wrconn, syncslotname, true);
 			}
 		}
@@ -1532,7 +1536,8 @@ ReportSlotConnectionError(List *rstates, Oid subid, char *slotname, char *err)
 		{
 			char		syncslotname[NAMEDATALEN] = {0};
 
-			ReplicationSlotNameForTablesync(subid, relid, syncslotname);
+			ReplicationSlotNameForTablesync(subid, relid, syncslotname,
+											sizeof(syncslotname));
 			elog(WARNING, "could not drop tablesync replication slot \"%s\"",
 				 syncslotname);
 		}

src/backend/replication/logical/tablesync.c

@@ -314,7 +314,8 @@ process_syncing_tables_for_sync(XLogRecPtr current_lsn)
 		 */
 		ReplicationSlotNameForTablesync(MyLogicalRepWorker->subid,
 										MyLogicalRepWorker->relid,
-										syncslotname);
+										syncslotname,
+										sizeof(syncslotname));
 
 		/*
 		 * It is important to give an error if we are unable to drop the slot,
@@ -462,7 +463,8 @@ process_syncing_tables_for_apply(XLogRecPtr current_lsn)
 				 */
 				ReplicationOriginNameForTablesync(MyLogicalRepWorker->subid,
 												  rstate->relid,
-												  originname);
+												  originname,
+												  sizeof(originname));
 				replorigin_drop_by_name(originname, true, false);
 
 				/*
@@ -871,27 +873,20 @@ copy_table(Relation rel)
  * pg_%u_sync_%u_UINT64_FORMAT (3 + 10 + 6 + 10 + 20 + '\0'), the maximum
  * length of slot_name will be 50.
  *
- * The returned slot name is either:
- * - stored in the supplied buffer (syncslotname), or
- * - palloc'ed in current memory context (if syncslotname = NULL).
+ * The returned slot name is stored in the supplied buffer (syncslotname) with
+ * the given size.
  *
  * Note: We don't use the subscription slot name as part of tablesync slot name
  * because we are responsible for cleaning up these slots and it could become
  * impossible to recalculate what name to cleanup if the subscription slot name
  * had changed.
  */
-char *
+void
 ReplicationSlotNameForTablesync(Oid suboid, Oid relid,
-								char syncslotname[NAMEDATALEN])
+								char *syncslotname, int szslot)
 {
-	if (syncslotname)
-		sprintf(syncslotname, "pg_%u_sync_%u_" UINT64_FORMAT, suboid, relid,
-				GetSystemIdentifier());
-	else
-		syncslotname = psprintf("pg_%u_sync_%u_" UINT64_FORMAT, suboid, relid,
-								GetSystemIdentifier());
-
-	return syncslotname;
+	snprintf(syncslotname, szslot, "pg_%u_sync_%u_" UINT64_FORMAT, suboid,
+			 relid, GetSystemIdentifier());
 }
 
 /*
@@ -901,9 +896,9 @@ ReplicationSlotNameForTablesync(Oid suboid, Oid relid,
  */
 void
 ReplicationOriginNameForTablesync(Oid suboid, Oid relid,
-								  char originname[NAMEDATALEN])
+								  char *originname, int szorgname)
 {
-	snprintf(originname, NAMEDATALEN, "pg_%u_%u", suboid, relid);
+	snprintf(originname, szorgname, "pg_%u_%u", suboid, relid);
 }
 
 /*
@@ -951,9 +946,11 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
 	}
 
 	/* Calculate the name of the tablesync slot. */
-	slotname = ReplicationSlotNameForTablesync(MySubscription->oid,
-											   MyLogicalRepWorker->relid,
-											   NULL /* use palloc */ );
+	slotname = (char *) palloc(NAMEDATALEN);
+	ReplicationSlotNameForTablesync(MySubscription->oid,
+									MyLogicalRepWorker->relid,
+									slotname,
+									NAMEDATALEN);
 
 	/*
 	 * Here we use the slot name instead of the subscription name as the
@@ -972,7 +969,8 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
 	/* Assign the origin tracking record name. */
 	ReplicationOriginNameForTablesync(MySubscription->oid,
 									  MyLogicalRepWorker->relid,
-									  originname);
+									  originname,
+									  sizeof(originname));
 
 	if (MyLogicalRepWorker->relstate == SUBREL_STATE_DATASYNC)
 	{

src/include/replication/slot.h

@@ -212,7 +212,7 @@ extern bool ReplicationSlotsCountDBSlots(Oid dboid, int *nslots, int *nactive);
 extern void ReplicationSlotsDropDBSlots(Oid dboid);
 extern void InvalidateObsoleteReplicationSlots(XLogSegNo oldestSegno);
 extern ReplicationSlot *SearchNamedReplicationSlot(const char *name);
-extern char *ReplicationSlotNameForTablesync(Oid suboid, Oid relid, char *syncslotname);
+extern void ReplicationSlotNameForTablesync(Oid suboid, Oid relid, char *syncslotname, int szslot);
 extern void ReplicationSlotDropAtPubNode(WalReceiverConn *wrconn, char *slotname, bool missing_ok);
 
 extern void StartupReplicationSlots(void);

src/include/replication/worker_internal.h

@@ -82,7 +82,8 @@ extern void logicalrep_worker_wakeup_ptr(LogicalRepWorker *worker);
 
 extern int	logicalrep_sync_worker_count(Oid subid);
 
-extern void ReplicationOriginNameForTablesync(Oid suboid, Oid relid, char *originname);
+extern void ReplicationOriginNameForTablesync(Oid suboid, Oid relid,
+											  char *originname, int szorgname);
 extern char *LogicalRepSyncTableStart(XLogRecPtr *origin_startpos);
 
 void		process_syncing_tables(XLogRecPtr current_lsn);