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.
Dovecot is running on a FreeBSD 6.1-RELEASE-p2 box where it has been stable for a couple months. Beta8 worked great! When I upgraded to rc2 from ports I made no configuration changes of any kind. rc2 is a pain to use here because of the constant hangs and delays.
Clients are Thunderbird 1.5.0.4 and 1.5.0.5 on FreeBSD 6.1, Ubuntu 6.06, and Windows XP SP2. All clients see the same problems, but they are most frequent on FreeBSD, even though that Thunderbird installation is identical (via rsync) to the one on Ubuntu. Changing Tbird's number of cached connections has no effect on the problems.
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.
A few other posters on this list reported similar problems, but I haven't seen any progress or resolution. Are others still having trouble? Does anyone know what was changed between dovecot versions that might have this affect? Any ideas for making it work well again?
Pete