[imp] Re: Hack concept - IMAP speedup

Andrew Morgan morgan at orst.edu
Wed Sep 8 15:46:35 PDT 2004

Check out Cyrus-IMAP, which is also on the list of products at


On Wed, 8 Sep 2004, Ross Becker wrote:

> I just got an email and went to look. I see two issues.
> 1. It does not contain an MDA- So when does it update the indexes after
> delivery?
> 2. It doesn't support maildir++ and quotas. I need quotas.
> It might be less work to add quotas to dovecot then add indexes to
> courier, though. I've just never heard of this IMAP server before now,
> so I'm not sure how widely used it is.  I searched for IMAP servers at
> www.imap.org too.  I'm guessing dovecot is pretty new?
> Cheers
>     Ross
> Paul Reilly wrote:
> > Look at Dovecot IMAP - www.dovecot.org
> >
> > We switched from Courier to Dovecot and noticed a huge performance
> > boost. Mainly because it keeps indexes.
> >
> > Paul
> >
> > On Wed, 8 Sep 2004, Ross Becker wrote:
> >
> >
> >>Just throwing this out, I'm really not certain as to which organizations
> >>I should be talking to about this, but Horde/IMP seems as good as any.
> >>
> >>Currently, free IMAP servers which are capable of webmail backend is bad
> >>for any organization which can allow large folders. The primary reason
> >>is that maildir (and maildir++) has no indexing at all. This means that
> >>to sort a folder, you have to open every message, read the headers, suck
> >>out the one(s) you need, and transform them into sortable format.  Once
> >>you've read every message, then you can sort.  This leads to woeful
> >>performance.  On a Pentium 4 with 800mhz memory bus, I clocked
> >>Courier-IMAP taking ~14 seconds to sort a 12.5k message folder by date.
> >>
> >>Clearly, for a webmail system, you want the server to be able to sort
> >>the messages fast, because all sorts will happen on the server.
> >>
> >>I'm looking at hacking (probably) procmail, and Courier-IMAP to maintain
> >>  fixed-length record files containing the message headers needed to
> >>support standard search and sort operations.  Not indexes, as that would
> >>require putting sorting code into the MDA (procmail).  At a wild guess,
> >>  this should provide at least an order of magnitude improvement in
> >>search and sort times.
> >>
> >>The ugliness is figuring out if procmail is the best delivery agent to
> >>add this hack to (I'm leaning there because of it's excellent support
> >>for delivery recipes & filters) and if there's any way this could be
> >>done in such a fashion that it could go into permanent project code.
> >>
> >>If anyone else here is interested in this hack, has thoughts, or
> >>whatever- I'm all ears.
> >>
> >>Cheers
> >>    Ross
> >>
> >>--
> >>IMP mailing list - Join the hunt: http://horde.org/bounties/#imp
> >>Frequently Asked Questions: http://horde.org/faq/
> >>To unsubscribe, mail: imp-unsubscribe at lists.horde.org
> >>
> >
> >
> --
> IMP mailing list - Join the hunt: http://horde.org/bounties/#imp
> Frequently Asked Questions: http://horde.org/faq/
> To unsubscribe, mail: imp-unsubscribe at lists.horde.org

More information about the imp mailing list