[horde] large session entries in horde_sessionhandler

[Michael M Slusarz]

Quoting liam hoekenga <liamr at umich.edu>:

>
>>> Is this new (or is storing the attachments new)?  We don't remember having
>>> having db errors before our upgrade.
>>
>> New as of 4.0.  But it's been in CVS for years now.
>
> How does this help the applications?

So we don't have to redo the (expensive) job of building the MIME 
structure for the message again.  And it is necessary to allow us to 
view message parts in separate windows.

> We're a large institution with a lot of users and we're finding the new
> behavior
> of the sessionhandler (storing a bunch of data in one row) has caused
> our MySQL
> server to exceed a 2GB linux memory limit fairly regularly.  When it exceeds
> the 2GB limit, it crashes...
>
> 050525 13:09:48  InnoDB: Error: cannot allocate 92163896 bytes of memory for
> InnoDB: a BLOB with malloc! Total allocated memory
> InnoDB: by InnoDB 1455758831 bytes. Operating system errno: 12
> InnoDB: Check if you should increase the swap file or
> InnoDB: ulimits of your operating system.
> InnoDB: On FreeBSD check you have compiled the OS with
> InnoDB: a big enough maximum process size.
> 050525 13:09:48  InnoDB: Warning: could not allocate 91163896 + 1000000
> bytes to
> retrieve
> InnoDB: a big column. Table name `sessions/horde_sessionhandler`
> 050525 13:09:48 [ERROR] Got error 139 when reading table
> './sessions/horde_sessionhandler'
> 050525 13:09:48  InnoDB: Fatal error: cannot allocate 102907440 bytes of
> InnoDB: memory with malloc! Total allocated memory
> InnoDB: by InnoDB 1364594855 bytes. Operating system errno: 12
>
>
> I see this in HEAD:
>
>    Should we cache the contents of the message contents across page loads
>    so that the IMAP server does not have to be accessed again? Note that
>    enabling this option will result in a significantly higher session size
>    (5 MB+ per user) so make sure your session backend can handle the 
> increased
>    storage demands.
>
> Does that mean we'll be able to turn this behavior off again?

No.  By default, IMP *doesn't* store the body contents in the session 
for the very reason it has the possibility of creating extremely large 
sessions.  This new config item is designed for those of us running IMP 
on small systems with minimal users to take advantage of caching the 
bodytext also.

michael

_______________________________________
Michael Slusarz [slusarz at curecanti.org]