[Koha-devel] Koha sessions table is ridiculously huge

Wed Feb 17 20:14:18 CET 2010

Clay,

Thanks!  That sounds like an easy enough enhancement to make.  I'll make it a point to keep an eye on the sessions table until then, and remind my coworkers to logout properly.

Cheers,

-Ian

From: koha-devel-bounces at lists.koha.org [mailto:koha-devel-bounces at lists.koha.org] On Behalf Of Clay Fouts
Sent: Wednesday, February 17, 2010 2:04 PM
To: Koha-devel
Subject: Re: [Koha-devel] Koha sessions table is ridiculously huge

You can also use "truncate sessions" to do the job if you just want to clear out the contents of the table. It's faster and simpler than using mysqldump.
This issue arises from the fact that the way Koha is written, if a user just walks away from a session without logging out, their session data will hang out in the the sessions table forever. A proper solution would involve adding a timestamp column to the sessions table, enabling one to cull only expired sessions entirely within SQL statements. With the current schema, you'd have to parse the contents of each row within a user program, then cull based on the expiry contained within the session data itself.

Cheers,
Clay

2010/2/17 Walls, Ian <Ian.Walls at med.nyu.edu<mailto:Ian.Walls at med.nyu.edu>>
Developers,

After performing a software upgrade and server reboot, I came across this problem.  My koha.sessions table is over 13 million entries.  This seems to indicate that entries into the table were never removed, and that may help to explain why my backup mysqldumps are increasing by around 4MB daily.

Chris Cormack suggested that I do a mysqldump of sessions with the no-data option set, then reimport it into the database to clear it out.  I've finally gotten sessions to tell me what indexes it has on it, so that can be recreated as well.  Are there any risks to doing this that I'm not factoring in?

More generally, what could be causing my sessions table to get so out of hand?  Permissions, perhaps?  Something in the code being off?

Any ideas or feedback would be appreciated.  Thanks!

Ian Walls
Systems Integration Librarian
NYU Health Sciences Libraries
550 First Ave., New York, NY 10016
(212) 263-8687

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