[horde] Database performance problem with Horde3/IMP4 with large user base

Luc Germain Luc.Germain at USherbrooke.ca
Fri Nov 25 11:51:34 PST 2005


to follow on the performance problem we reported a while back about 
slow permission database queries, is there any chance to see the 
permissions data out of the datatree and in its own table in release 
3.1? Should I file an enhancement request in the bug system for this?


Luc Germain, Support technique
Service des technologies de l'information
Université de Sherbrooke, Sherbrooke (Québec) Canada  J1K 2R1
émail: Luc.Germain at USherbrooke.ca

Selon Chuck Hagenbuch <chuck at horde.org>:

> Quoting Luc Germain <Luc.Germain at USherbrooke.ca>:
>> Concerning the database performance problem reported last week for horde
>> v3 with a large user base, I did some simulations on our database, and
>> I can confirm that the requests that generate a heavy load on the
>> database server are those that evaluate permissions on the datatree
>> table, like this one:
>> SELECT c.datatree_id, c.datatree_name FROM horde_datatree c LEFT JOIN
> [etc]
>> Apart from redesigning the database, the only way I see to support lots
>> of concurrent users would be to cache the results of these permissions
>> evaluation requests in the user session for some configurable time. Is
>> it a solution that would be acceptable to horde developers? Would it be
>> easy to implement?
> I would love to work on this but I'm extremely busy right now. If
> someone wanted to do code for it, just look at the History changes and
> send it in.
> As for caching, caching in the session would be pretty easy; if we're
> careful it shouldn't even affect session size too much. The flip side
> is that permissions changes would take a logout/login cycle to show up
> - would that be acceptable to people? (yes, if you initiate the change
> yourself, it can be flushed from _your_ session, but flagging other
> sessions would be tricky and might end up losing us the performance
> gains anyway).
> -chuck
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