a tale of bugzilla performance
a high-level goal across multiple teams this year is to improve bugzilla.mozilla.org’s performance, specifically focusing on the time it takes to load a bug (show_bug.cgi).
towards this end, in q1 2014 i focused primarily on two things: implementing a framework for bugzilla to use memcached, and deep instrumentation of bmo in our production environment to help identify areas which require optimisation and could leverage memcached.
i’ll talk more about memcached in a later blog post. today i’ll talk about a single little query.
the data gathered quickly identified a single query used to determine a user’s group membership was by far the slowest query, averaging more than 200 ms to complete, and was executed on every page: