Hi Everyone,
just a wanted to post a quick summary of what I did today in order to
significantly reduce the SiteStore related memcached traffic.
I stumbled upon this comment
https://phabricator.wikimedia.org/T58602#808530 and thus poked a bit at
when we load sites from memcached. During that I found that we still
were loading the sites basically all the time. To get the number of that
down, I uploaded the following patches that have been reviewed, merged
and even deployed yet (thanks for the reviews Daniel and Katie):
* Don't lookup Sites from mc for the 'languageLinkSiteGroup' setting:
https://gerrit.wikimedia.org/r/177419
* Don't load all sites for LangLinkHandler:
https://gerrit.wikimedia.org/r/177429
* Don't access sites on WikibaseClient::getEntityIdForTitle:
https://gerrit.wikimedia.org/r/177434
That lead to a noticeable memcached traffic change (see attachment).
Memcached traffic graphs:
https://ganglia.wikimedia.org/latest/graph_all_periods.php?c=Memcached%
20eqiad&m=cpu_report&r=hour&s=by%
20name&hc=4&mc=2&st=1417641558&g=network_report&z=large
I still have
https://gerrit.wikimedia.org/r/177416 in review, which
slightly changes the behavior of the other projects sidebar, but I think
that this change also has quite some potential to reduce memcached
traffic even further. Would be great if we could get that ready for
backporting until Monday.
Cheers,
Marius
