As you may know mydumper is multithreaded and this adds a lot of complexity compared with other logical backup tools as it also needs to coordinate all threads with the same snapshot to be consistent. So let review how mydumper does this with the default settings.
By default mydumper uses 4 threads to dump data and 1 main threadMain Thread
- FLUSH TABLES WITH READ LOCK
- START TRANSACTION WITH CONSISTENT SNAPSHOT;
- dump non-InnoDB tables
- UNLOCK TABLES
- dump InnoDB tables