[Dovecot] observations about delays
I've tried two imap clients (mahogany and Mozilla) and they both have strange delays and weird failures. As a reminder, I am using mbox format mailboxes on the server and client side filtering of messages from the inbox.
In both cases when the client fetches messages from the inbox and starts redistributing them, CPU utilization on the imap server goes to around 40 percent for Mozilla and around 90 percent for mahogany. There are long delays on the order of two minutes when filtering messages. or 30 to 50 seconds when opening a mailbox.
Other than the performance problems, Mozilla is relatively well-behaved. Mahogany on the other hand is a bit more rough and (not) ready. It uses c-client for its imap code and during the filter driven message redistribution process, it all of a sudden started started complaining about unexpected EOF and I found one corrupted message:
on 31/8/03 7:36 pm, Morten Christensen at ipcop-d@indbakke.dk wrote:
These bugs might keep many people from trying a new alpha with interesting improvements.
A more detailed help for fixing them after install is needed.
OK, I'll have a From esj@harvee.org Sun Aug 31 16:01:21 2003 Return-Path: ipcop-devel-admin@lists.sourceforge.net Received: from red.harvee.home (red [192.168.25.1] (may be forged)) by harvee.org (8.12.8/8.12.8) with ESMTP id h7VK1KiE029762 for esj@harvee.billerica.ma.us; Sun, 31 Aug 2003 16:01:20 -0400 Received: from sc8-sf-list2.sourceforge.net (lists.sourceforge.net [66.35.250.206]) by red.harvee.home (8.11.6/8.11.6) with ESMTP id h7VK1I111902 for esj@harvee.billerica.ma.us; Sun, 31 Aug 2003 16:01:19 -0400 Received: from sc8-sf-list1-b.sourceforge.net ([10.3.1.13] helo=sc8-sf-list1.sourceforge.net)
I had read this message before it was filtered and moved to the right mailbox. It was complete then. Now it's not so happy.
How can I gather more data to make it possible to debug these problems.
---eric
On Monday, Sep 1, 2003, at 00:52 Europe/Helsinki, Eric S. Johansson wrote:
In both cases when the client fetches messages from the inbox and starts redistributing them, CPU utilization on the imap server goes to around 40 percent for Mozilla and around 90 percent for mahogany.
There are long delays on the order of two minutes when filtering messages. or 30 to 50 seconds when opening a mailbox.
Check what Dovecot is doing at the time. Use rawlog (or network sniffer) and strace.
Other than the performance problems, Mozilla is relatively well-behaved. Mahogany on the other hand is a bit more rough and (not) ready. It uses c-client for its imap code and during the filter driven message redistribution process, it all of a sudden started started complaining about unexpected EOF and I found one corrupted message:
Humm.. If it copies a message from a mailbox to itself, that could break mbox, or at least complain about some errors.. Could it be that?
Timo Sirainen explained:
On Monday, Sep 1, 2003, at 00:52 Europe/Helsinki, Eric S. Johansson wrote:
In both cases when the client fetches messages from the inbox and starts redistributing them, CPU utilization on the imap server goes to around 40 percent for Mozilla and around 90 percent for mahogany.
There are long delays on the order of two minutes when filtering messages. or 30 to 50 seconds when opening a mailbox.Check what Dovecot is doing at the time. Use rawlog (or network sniffer) and strace.
will do. should I be using the latest from cvs or from 99.10 like I have been?
Humm.. If it copies a message from a mailbox to itself, that could break mbox, or at least complain about some errors.. Could it be that?
I don't believe so. The mahogany filters were under construction to meet my needs here. I am looking forward to server side filtering because I am getting rather tired of replicating 100+ filters every time I change clients.
participants (2)
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Eric S. Johansson
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Timo Sirainen