On Tue, Apr 16, 2013 at 12:14 AM, Tim Starling <tstarling(a)wikimedia.org>wrote;wrote:
We've been using it as a memcached replacement for
session storage
since the eqiad switchover in January, because it has a replication
feature which can be used to synchronise data between the two data
centres. It allowed us to switch from Tampa to Ashburn without logging
everyone out.
It's designed more as a persistent store than a cache. Memcached still
wins for simple unreliable object caching, so we're still using
memcached for that.
We previously stored the MW job queue in MySQL. This gave us lots of
useful features, like replication and indexing for duplicate removal,
but it has often been hard to manage the performance implications of
the high insert rate.
Among its many features, Redis embeds a Lua interpreter on the server
side. The new Redis job queue class provides a rich feature set
superior to the MySQL job queue, primarily by the use of several
server-side Lua scripts which provide high-level job queue functions.
I've taken the liberty of adapting this explanation and my own additions
for the Redis page on
MediaWiki.org
Steven