Ensure ThisTimeLineID is valid before START_REPLICATION

Craig Ringer

src/backend/replication/walsender.c

@@ -488,6 +488,11 @@ StartReplication(StartReplicationCmd *cmd)
 	StringInfoData buf;
 	XLogRecPtr	FlushPtr;
 
+	if (ThisTimeLineID == 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("IDENTIFY_SYSTEM has not been run before START_REPLICATION")));
+
 	/*
 	 * We assume here that we're logging enough information in the WAL for
 	 * log-shipping, since this is checked in PostmasterMain().