moving ezsession - user cache info to memcache

Saturday 30 August 2008 2:02:28 am

Hi

We are thinking about moving ezsession to memcache.
Somebody have already try it?

In more case our system crash because we have a lot of query on the ezsession table
and the table is lock all the time.
Of course we can use a master/slave database but it won't resolve all the pb.

http://www.kouz-cooking.fr

Sunday 31 August 2008 7:18:29 am

Haven't tested it, but a first step to be able to have custom session handler (without hacking ezp):
http://issues.ez.no/IssueView.php?Id=13443&

The recommendations I've seen online is to use memcache for cache, but keep db as the storage. In other words get data from db if it's not yet in memcache, and have a flag that says if session has been written to. If it has, then write session data from cache to db at the end of the request ( with eZExecution::addCleanupHandler ).

eZ Online Editor 5: http://projects.ez.no/ezoe || eZJSCore (Ajax): http://projects.ez.no/ezjscore || eZ Publish EE http://ez.no/eZPublish/eZ-Publish-Enterprise-Subscription
@: http://twitter.com/andrerom

Sunday 31 August 2008 1:41:50 pm

>I would like to know why the sessions are stored in db and why when there's a lot of simultaneous >connections the db querries are so slow.
>Is memcache a real alternative to the actual mechanism ?

Not tried yet for sessions, but while the response time with memcached isn't that much faster than a DB under low load, it scales much better under high load.

What is scheduled for development soon (right after 4.1 is released -- which won't take that long), is a refactoring of all cache mechanisms (and add it for places in the kernel which are eligible for caching). The basic idea is:

- introduce hierarchical caching in front of persistent storage
- you can turn this on/off depending on your needs
- clustering is taken into account upfront

As the design phase is not finished at this point, I'm reluctant to tell you more now, but for bleeding edge discussions, feel free to contact me directly. Once the details are known, it will be shared with all

Best regards
Paul

eZ Publish, eZ Find, Solr expert consulting and training
http://twitter.com/paulborgermans

Monday 01 September 2008 12:46:14 am

afaict, the best approach to scalability would be not using memcache, but rather putting all the session info in the cookie, and encrypt it. Yahoo does it (they use custom-built php extensions for doing the encryption at the desired speed).

That could work to, but we would need to use one of the standard php extensions for encryption(imho).
And we would need to change all sensitive data storage to use ezpreference or something similar, encryption or not, some of our clients have higher security requirements then the average web app(also imho).

eZ Online Editor 5: http://projects.ez.no/ezoe || eZJSCore (Ajax): http://projects.ez.no/ezjscore || eZ Publish EE http://ez.no/eZPublish/eZ-Publish-Enterprise-Subscription
@: http://twitter.com/andrerom

Monday 01 September 2008 9:53:13 am

@Stephane: we'll consider it as part of 4.1, in which many more performance patches and a refactoring of the autoload mechanisms will be done

hth

Paul

eZ Publish, eZ Find, Solr expert consulting and training
http://twitter.com/paulborgermans

Thursday 06 May 2010 1:03:51 am

Hi all.

Months later, is there any news on ez publish and memcache support ?

I found those community extensions :

1. http://projects.ez.no/lamemcache
2. http://projects.ez.no/memcachedcluster

Do you have any feedback ?

Is there another way to use memcache ?

How to use memcache for ezpublish cache ? 

Thanks.