Call pg_switch_wal() on replica after pg_create_restore_point() during pg_stop_backup()

Author: Arthur Zakirov

src/backup.c

@@ -80,7 +80,7 @@ static void backup_files(void *arg);
 static void do_backup_database(parray *backup_list);
 
 static void pg_start_backup(const char *label, bool smooth, pgBackup *backup);
-static void pg_switch_wal(void);
+static void pg_switch_wal(PGconn *conn);
 static void pg_stop_backup(pgBackup *backup);
 static int checkpoint_timeout(void);
 
@@ -642,7 +642,7 @@ pg_start_backup(const char *label, bool smooth, pgBackup *backup)
 	 * Do not switch for standby node and if backup is stream.
 	 */
 	if (!from_replica && !stream_wal)
-		pg_switch_wal();
+		pg_switch_wal(backup_conn);
 	if (!stream_wal)
 		/*
 		 * Do not wait start_lsn for stream backup.
@@ -656,20 +656,20 @@ pg_start_backup(const char *label, bool smooth, pgBackup *backup)
  * Switch to a new WAL segment. It should be called only for master.
  */
 static void
-pg_switch_wal(void)
+pg_switch_wal(PGconn *conn)
 {
 	PGresult   *res;
 
 	/* Remove annoying NOTICE messages generated by backend */
-	res = pgut_execute(backup_conn, "SET client_min_messages = warning;", 0,
+	res = pgut_execute(conn, "SET client_min_messages = warning;", 0,
 					   NULL);
 	PQclear(res);
 
 	if (server_version >= 100000)
-		res = pgut_execute(backup_conn, "SELECT * FROM pg_switch_wal()", 0,
+		res = pgut_execute(conn, "SELECT * FROM pg_switch_wal()", 0,
 						   NULL);
 	else
-		res = pgut_execute(backup_conn, "SELECT * FROM pg_switch_xlog()", 0,
+		res = pgut_execute(conn, "SELECT * FROM pg_switch_xlog()", 0,
 						   NULL);
 
 	PQclear(res);
@@ -973,6 +973,9 @@ pg_stop_backup(pgBackup *backup)
 			restore_lsn = (XLogRecPtr) ((uint64) xlogid << 32) | xrecoff;
 			PQclear(res);
 
+			/* Switch WAL on master to retreive restore_lsn */
+			pg_switch_wal(master_conn);
+
 			/* Wait for restore_lsn from master */
 			while (true)
 			{