diff --git a/client/mysqldump.c b/client/mysqldump.c index 540f0d78c50..498a10041a9 100644 --- a/client/mysqldump.c +++ b/client/mysqldump.c @@ -2050,8 +2050,18 @@ static int do_show_master_status(MYSQL *mysql_con) static int do_flush_tables_read_lock(MYSQL *mysql_con) { + /* + We do first a FLUSH TABLES. If a long update is running, the FLUSH TABLES + will wait but will not stall the whole mysqld, and when the long update is + done the FLUSH TABLES WITH READ LOCK will start and succeed quickly. So, + FLUSH TABLES is to lower the probability of a stage where both mysqldump + and most client connections are stalled. Of course, if a second long + update starts between the two FLUSHes, we have that bad stall. + */ return - mysql_query_with_error_report(mysql_con, 0, "FLUSH TABLES WITH READ LOCK"); + ( mysql_query_with_error_report(mysql_con, 0, "FLUSH TABLES") || + mysql_query_with_error_report(mysql_con, 0, + "FLUSH TABLES WITH READ LOCK") ); }