How to debug Lock wait timeout exceeded on MySQL?

Question

In my production error logs I occasionally see:

SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction

Answer 1

Activate MySQL general.log (disk intensive) and use mysql_analyse_general_log.pl to extract long running transactions, for example with :

--min-duration=your innodb_lock_wait_timeout value

Disable general.log after that.