[imp] problems with large numbers of mailboxes

[Scott Dellinger]

I am finding that users with large numbers of mailboxes (somewhere over about 577, but larger numbers like 800, consistently) are not working correctly in IMP 5.0.17.  In the dynamic view, the page loads ok but any subsequent request results in the user being logged out on the server (as seen in the logs) and the user receives an error about communicating with the server.  A subsequent click returns the user to the login page.  In the traditional view (which we’re not using, but I tested for this), the mailbox list is never displayed, I see the user logout in the server log, and the first click on anything results in a redirect to the login page.

A couple of us have mass-created mailboxes so we could test this, and it seems consistent for us (creating lots of mailboxes leads to the user having the issue, removing them makes it go away).  If I enable IMAP debugging, the session looks pretty ordinary when compared with that of a user with a smaller number of mailboxes during initial login, but no commands get sent following that.  During some debugging, I saw that in imp/lib/Ajax/Application.php’s showMessage() function, which gets called when a user clicks a message, the line:

	$GLOBALS['injector']->getInstance('IMP_Factory_Imap')->create()->openMailbox($this->_mbox, $rw ? Horde_Imap_Client::OPEN_READWRITE : Horde_Imap_Client::OPEN_AUTO);

never returns, so I’m presuming this means something has gone awry with the IMAP session.  

Any ideas on what could be happening, before I start delving into IMAP code?


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Scott Dellinger
Systems Architecture & Administration
Enterprise Technology Services
The University of Vermont