… FLUSH TABLES WITH READ LOCK does not work as optimally as you could think it works. Even though with general lock compatibility guidelines Read Lock should not conflict with another Read Lock… | Query | 681 | Waiting for table flush | flush tables with read lock | 0 | 0 | 1 | | 10291 | root | localhost | dumptest | Query | 74 | Waiting for global read lock | insert into C values…

… with FLUSH TABLES WITH READ LOCK you are getting in some cases a snapshot that is not recoverable’ I mean that i work in an environment with… have been experiencing this with many versions of MySQL. We are now using ‘service mysql stop’ instead of FLUSH TABLES WITH READ LOCK to get reliable…

… Locking the table to prevent writes to it. I think you’re correct in theory as FLUSH TABLES WITH READ LOCK suppose to flush tables not just make them read only. Most tools however do not need FLUSH PART (for Innodb tables) and might…

Even killing FLUSH TABLES WITH READ LOCK won’t resolve the deadlock as of MySQL 5.5 – other queries will still be stuck in ‘Waiting for table flush‘ even after the FLUSH TABLES WITH READ LOCK goes away. http://bugs.mysql.com/bug.php?id=44884

… hot backup problems with my friends, for percona xtrabackup, i think there are three problems which forced us using FLUSH TABLES WITH READ LOCK. 1. copy… following requirements, we can do a hot backup without using FLUSH TABLES WITH READ LOCK: 1. do not do any ddl operations in the progress…

… do you mean by “snapshot what is recoverable”. Even without Flush tables with read lock, LVM snapshot should be recoverable 100% of the time. You… synchronization of binary log and innodb snapshot. In certain versions FLUSH TABLES WITH READ LOCK would not block “commit” operation which caused wrong binary log…

…. That is: Even with FLUSH TABLES WITH READ LOCK you are getting in some cases a snapshot that is not recoverable. Apparently, FTWRL locks frontend threads, but some backend InnoDB can still go on and play with tables? That worries me at…

Kristian, I agree with Mark. It would be great to find the bug if … with LVM or something. As mark mentions – indeed there are known problems which are not handled if you have DDL however FLUSH TABLES WITH READ LOCK…

… fixed it in Percona Server. Also if you’re doing FLUSH TABLES WITH READ LOCK anyway you can consider doing SHOW SLAVE STATUS/SHOW MASTER…