So we had some similar problems related to running our rails application
using either memcache or an sql-based sessioning solution using a number
of mongrels with Apache's balancer. In the end, I think the problem we
had was related to a race condition when setting session data between
ajax calls. On the rails trac instance, there has been a plugin
developed for these types of conditions called smartsessionstore. It
works with the sql_session plugin, meaning your sessioning will be sql
based so not quite as fast as memcache, but I'm not sure if the
difference is actually noticable to users. Here's the link:
http://www.texperts.com/2007/05/01/race-conditions-in-rails-sessions-and
-how-to-fix-them/
--TR
________________________________
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of cleaner416
Sent: Friday, September 07, 2007 10:37 AM
To: mongrel-users@rubyforge.org
Subject: [Mongrel] memcached and fragment storage,session
storage with a mongrel cluster
Greetings,
I posted this not on the Rails mailing list and didn't get a
definitive
response so I thought I'd post it here, since I figure lots of
you are using
mongrel with Rails apps. Any suggestions would be greatly
appreciated.
I've been using file-based fragment caching and DB-based session
caching quite extensively. I decided to try out memcached for
both to
see if I could achieve a meaningful performance gain for a
particular app.
I searched around a bit and simply added two lines to my
development.rb:
config.action_controller.fragment_cache_store = :mem_cache_store
config.action_controller.session_store = :mem_cache_store
(I also changed config.action_controller.perform_caching = true
for
testing )
This works like a charm on my development box. (Mac) I've got
memcached -vv
running in another terminal window I can see it doing it's
thing.
However, as soon as I tried this on my production box, (by
adding the
above lines to production.rb) I ran into some odd problems. My
production setup is pretty vanilla: Apache 2.2 load balancing to
a
couple of mongrel instances via mongrel cluster on a fedora core
5
box. It seems as if a memcache pool is being created for each
mongrel instance, instead of the app. Is there some other kind
of
config I need to do in production.rb? The stuff I've found via
googling seems to apply to Rails < 1.2
Thanks much
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