[dev] Authentication session data cleaned by Kronolith

[Michael M Slusarz]

  Quoting Rui Carneiro <rui.arc at gmail.com>:

>  
>   On Tue, Jun 25, 2013 at 2:42 PM, Michael M Slusarz <slusarz at horde.org>
> wrote:
>
>> Quoting Rui Carneiro <rui.arc at gmail.com>:
>>
>>> I don't know if my issue is the same from the original thread but here
>>> it
>>> goes.
>>>
>>> My sessions are also being clear but by IMP. Everything work just fine
>>> with
>>> "normal" accounts but when I login into a very large account (p.e. 70k
>>> messages on the inbox) the session is destroyed (I am assuming this
>>> since I
>>> am redirected to the logout page).
>>>
>>> My current driver for the SessionHandler is Memcache. If I use File
>>> everything works as expected.
>>
>> You *really* shouldn't be using memcache as a sessionhandler backend.
>>  If using on a system with many users, you are most likely going to run
>> out of the larger memory slices fairly quickly - which will cause
>> sessions to be dropped due to the FIFO allocation.
>>
>> A mailbox with 70,000 messages requires a large data structure to
>> represent.  You may in fact be reaching the memcache max size limit of
>> 1 MB.
>
>     
>    We are indeed passing the 1MB size limit but shouldn't this be
> supported with the large_items config?

Not necessarily.  There are a finite number of large slabs allocated  
by memcache.  If on a server with a number of users, these large slabs  
are necessarily limited (especially if caching other data), so they  
are potentially going to get reallocated to another user.  This will  
cause the original user's session data to be incomplete, and their  
session will be invalidated/timeout.

Again - you *really* should not be using memcache as a session  
handler.  It was never designed for this purpose.  It is 2013 - there  
are better, higher-performing alternatives available these days.

michael

___________________________________
Michael Slusarz [slusarz at horde.org]