Non-deterministic updates causing problems for DB replication

[andrewjpage]

We run delayed job on a MySQL server with replication.

110309 9:46:23 [Warning] Statement may not be safe to log in statement format. Statement: UPDATE delayed_jobs SET locked_at = '20
11-03-09 09:46:23', locked_by = 'delayed_job.0 host:xxxxx pid:24192' WHERE ((run_at <= '2011-03-09 09:46:23' AND (locked_at IS NULL
OR locked_at < '2011-03-09 05:46:23') OR locked_by = 'delayed_job.0 host:xxxxx pid:24192') AND failed_at IS NULL) LIMIT 1

There appears to be non-deterministic updates, and when the SQL statement above is sent to the replication slave, the slave may update a different row to that which was updated on the master. The indeterminacy is caused by the "LIMIT 1" clause, which effectively returns a random row which satisfies the WHERE clause.

[betamatt]

You should update to the latest version of delayed_job which removes this update.

[andrewjpage]

Thanks
Andrew

On 10 March 2011 13:40, betamatt
reply@reply.github.com
wrote:

You should update to the latest version of delayed_job which removes this update.

#219 (comment)