[Bug 142303] New: kmail/kio_imap4 unrecoverable hang when accessing large (~100k+) mails across WAN link

[Mike Culbertson]

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http://bugs.kde.org/show_bug.cgi?id=142303         
           Summary: kmail/kio_imap4 unrecoverable hang when accessing large
                    (~100k+) mails across WAN link
           Product: kmail
           Version: 1.9.1
          Platform: Gentoo Packages
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
        AssignedTo: kdepim-bugs kde org
        ReportedBy: mike xenter net


Version:           1.9.1 (using KDE KDE 3.5.6)
Installed from:    Gentoo Packages
Compiler:          gcc version 4.1.1 (Gentoo 4.1.1-r3) 
OS:                Linux

Client: Kmail 1.9.1 w/ KDE 3.5.6 on Gentoo
Server: Exchange 5.5
Network: FW-to-FW VPN, bandwidth ~1.5Mbps

This is similar to other bugs, but not exact.  This behavior is 100% reproducable for me, and happens with any mail roughly 100K or bigger, with or without attachments.

The client is at a remote site, accessing the mail server across a firewall-to-firewall VPN connection.  Any interaction with a large mail in the message list results in an attempt to fetch the message, which then hangs at anywhere from 5-25% complete.  This does not clear up over time (I left it sitting for 24 hours once).  Once this happens, trying to cancel the task results in the cancellation hanging instead.  Selecting any other mails or folders on the same server fails (blank message window, no errors) once the hang has started.

The only solution I've found is to exit kmail, then manually kill off the kio_imap4 processes.  If I don't kill the kio_imap4, restarting kmail does no good.  No other mail clients I've tried (Thunderbird, Outlook, pine) exhibit the same behavior.  There are no errors reported at any stage except occasional warnings when killing kio_imap4.

-Mike Culbertson