[imp] Re: IMP authentication and email access very slow

[Craig White]

On Fri, 2005-02-11 at 17:13 +0000, Gavin Kelman wrote:
> Jan Schneider wrote:
> > Zitat von Gavin Kelman <gavin.kelman at uk.lionbioscience.com>:
> >>Is there a way to enable debugging in IMP so that I can see
> >>_exactly_ what's going on with IMP <-> IMAP server communication?
> > 
> > No, because not IMP is doing the communication, but the c-client 
> > library compiled into PHP.
> 
> Fair enough.
> 
> >>With the Horde authentication set to use IMP as the authentication
> >>method, logins take about 15-30 seconds. With Horde set to use the
> >>IMAP server directly, logins take about 0.5 seconds. If I then go
> >>to IMP and login again, it take 15-30 seconds to login.
> > 
> > This is not *that* unusual, because there are a lot of tasks done by 
> > IMP on login.
> 
> It used to be a heck of a lot faster. I'd be unimpressed if it's usually
> this slow on a dual 2.4ghz machine with 2GB RAM for one user.
> 
> >>With either authentication method set, _most_ of the time, once
> >>logged in, selecting other folders and viewing messages is very
> >>fast now (I've also enabled folder caching), but 5% or so of the
> >>time, selecting a different mail folder takes a good 5-30 seconds
> >>to change.
> > 
> > This sounds like temporary timeouts, e.g. during DNS lookups of PGP key 
> > server timeouts.
> 
> The PGP timeout is set to 1. Local nameservers are all working fine, and
> I'd expect some DNS caching to speed things up after logging in the
> first time.
> 
> I've started to do some tests against our IMAP server. Telnetting to it
> on port 143 and doing '. login username password' is fine, but then
> '. list "" *' takes anything upto 30 seconds. Thus, leading me to
> believe it's our Cyrus IMAP server at fault. Squirrelmail somehow brings
> up the folder list in no time at all.
> 
> Getting a bit off topic now, but does anyone know why Cyrus would take
> _SUCH_ a long to return a folder list with the '. list "" *' command?
----
It would seem to me - and I am not all knowledgable on these matters,
that in a way, you have answered your own question. You can't expect IMP
to return the folder list faster than a direct telnet to the imap server
would unless it somehow kept a cache of the folder list and provided you
the list of mailboxes before it received them from your imap server.

Cyrus comes with a number of utilities to 'reconstruct' your mailboxes
and it would seem useful to try this function out and see if that helps.

Craig