[Dovecot] critical performance problem

[Timo Sirainen]

On Tue, 2007-02-20 at 11:41 +0100, Rene Luria wrote:
> > Just tried installing alpha4 and then upgrading to rc22. rc22 reads
> > alpha4's index files just fine, although cache file got truncated (that
> > should happen only with 64bit systems).
> 
> As I began this thread, in terms of operations or functionalities, the
> upgrade is transparent. Everything works.
> 
> Moving to 1.0.rc22 makes load raise up to 200 or more
> Downgrading back to 1.0alpha4 gets the load back to normal (after a few
> hours)

Well, since I'm out of ideas I can't do anything about it without
knowing more specifically what is causing the problem.

One thing you could try is what happens to load if you add :INDEX=MEMORY
to default_mail_env in alpha4. If it doesn't raise the load too high (if
you're not using webmail it shouldn't) try upgrading to rc22 with
the :INDEX=MEMORY also and see if the load stays the same or if it's
still raising to 200. If it's the same then the problem is clearly
related to index files.

Or you could try doing some test rc22 installation running in a
different port, then try with some test users if you can figure out (eg.
with strace) what it's doing wrong (constantly rebuilding index files?).

The problem might also be related to deliver and not to imap/pop3 at
all. You could try running the old deliver with its own config file
and :INDEX=MEMORY and upgrade the rest of the Dovecot to see if that
makes a difference.

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