Description:
In MySQL 5.5/5.6/5.7 manual said this example issue FTWRL(Flush Table With Read Lock).
shell> mysqldump --single-transaction --all-databases > backup_sunday_1_PM.sql
Manual:
https://dev.mysql.com/doc/refman/5.5/en/backup-policy.html
https://dev.mysql.com/doc/refman/5.6/en/backup-policy.html
https://dev.mysql.com/doc/refman/5.7/en/backup-policy.html
But these options don't issue FTWRL. The source code are here.
~/client/mysqldump.c
5811 if ((opt_lock_all_tables || opt_master_data ||
5812 (opt_single_transaction && flush_logs)) &&
5813 do_flush_tables_read_lock(mysql))
5814 goto err;
FTWRL is only issue with --master-data, or --flush-logs with --single-transaction.
How to repeat:
Set general_log=on, and issue the example. There is no FTWRL
.
2017-06-22T08:14:05.953699Z 15 Connect root@localhost on using TCP/IP
2017-06-22T08:14:05.954699Z 15 Query /*!40100 SET @@SQL_MODE='' */
2017-06-22T08:14:05.954699Z 15 Query /*!40103 SET TIME_ZONE='+00:00' */
2017-06-22T08:14:05.958699Z 15 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2017-06-22T08:14:05.959699Z 15 Query START TRANSACTION /*!40100 WITH CONSISTENT SNAPSHOT */
2017-06-22T08:14:05.959699Z 15 Query SHOW VARIABLES LIKE 'gtid\_mode'
2017-06-22T08:14:05.964699Z 15 Query UNLOCK TABLES
Suggested fix:
Modify Exampl like this.
shell> mysqldump --single-transaction --all-databases --master-data > backup_sunday_1_PM.sql
or
shell> mysqldump --single-transaction --all-databases --flush-logs > backup_sunday_1_PM.sql
