pt-online-schema-change results in many more deadlocks under MySQL 5.6

[Brian Durand]

I recently tried running pt-online-schema-change on a large (56M+ row) active table (many reads and writes to it per second) under MySQL 5.6 (Oracle community edition). It resulted in many deadlocks and I had to shutdown the process. Playing with chunk size and max-load threads only had any effect if I reduced them to values so low that the schema change was going to take 2 days to finish.

I had recently run a pt-online-schema-change on this same table with no such deadlocks when we were still on Percona Server 5.5.

[Daniel Nichter (daniel-nichter)]

I'm not sure why MySQL 5.6 would deadlock more than PS 5.5. Are you using the same version of pt-online-schema-change? Can you provide any more insight into what's happen, like what's deadlocking, what lock-wait timeouts you're using, etc.

[Daniel Nichter (daniel-nichter)]

I doubt this is a bug, so I'm going to close this. Brian: you can email me at my first name @percona.com, or http://www.percona.com/forums/ might be a good place to ask and get input from other users. We have used pt-osc on very high workloads, and so far locking issues have not been revealed to be a bug in the tool.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-1102