[horde] large session entries in horde_sessionhandler

[liam hoekenga]

>> 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?

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?

Liam