Timo Sirainen wrote:
On Sun, 2006-07-30 at 18:48 -0700, Pete Slagle wrote:
I posted about this previously, but for whatever reason there hasn't been much of a response.
I upgraded from beta8 to rc2, and dovecot IMAP went from being fast and responsive to being painfully slow and often hanging Thunderbird. (I made no configuration changes to my dovecot configuration file which is here: http:/x15.us/dovecot.conf)
The main issue seems to be about deleting messages (or moving them). Delete operations often, but not always, hang for many seconds or minutes.
Could you start tracing the imap process when it happens, stop it when it's over and show me the results? Also is the process at the time eating all the CPU? Is the memory usage growing?
See http://wiki.dovecot.org/Debugging/ProcessTracing
I did a little experimentation and found a sure work around: I stop the dovecot server, run 'rm ~/Maildir/dov*' on my server home directory, and restart dovecot. The problems are immediately gone, for a while, then they gradually return. This seems to indicate there is some kind of index problem or corruption on the server side, but I'm not certain.
Well, that removed both the index files and dovecot-uidlist file. If you only remove dovecot.index* does it fix it? What if you remove only dovecot.index.cache?
How large are those dovecot* files when it's running slow?
I'll do some testing as suggested over the next few days and report back. Here are the answers to your questions that I can tell you now:
During hangs the there is no significant CPU utilization (less than 1%) by dovecot processes on the server. On the client, usually Thunderbird uses no CPU, but sometimes it uses all available.
I recently cleared the dovecot files in my top Maildir directory, so I don't know how indicative the files sizes are. The whole Maildir directory tree contains about 70,000 messages in about 1000 nested subfolders. The dovecot files in the top directory are:
65 Jul 31 09:34 Maildir/dovecot-keywords1622 Jul 31 15:13 Maildir/dovecot-uidlist 896 Jul 31 15:13 Maildir/dovecot.index 58368 Jul 31 15:08 Maildir/dovecot.index.cache 15752 Jul 31 15:13 Maildir/dovecot.index.log
Just now I got the first error message (ever!) during a hang. A Thunderbird message box reported a server error. The server log, full of connect and disconnect messages, showed only these two errors, in this order, at the end:
dovecot: 2006-07-31 15:07:38 PDT Error: IMAP(pete): Fixed index file /home/pete/Maildir/.In - lists.dovecot/dovecot.index: first_recent_uid_lowwater 1516 -> 1515 dovecot: 2006-07-31 15:07:38 PDT Error: IMAP(pete): Corrupted index file /home/pete/Maildir/.In - lists.dovecot/dovecot.index: Duplicate header extension keywords
The sizes of the files in the directory that had the error are as so:
17 May 25 09:04 dovecot-keywords
202 Jul 31 12:44 dovecot-uidlist
1200 Jul 31 15:07 dovecot.index53248 Jul 31 12:23 dovecot.index.cache 12972 Jul 31 15:07 dovecot.index.log 131088 Jul 22 13:36 dovecot.index.log.2
Pete