DBLocker / High Load / IMP ... ?

E.M. Recio erecio at storm.jmc.tju.edu
Mon Apr 7 12:22:48 EDT 2003

On Mon, 7 Apr 2003, Mika Iisakkila wrote:

> > On Sun, 6 Apr 2003, Elmo Recio wrote:
> >>I noticed, however, that when I disable IMP (from a remote machine), the
> >>server load goes down significantly. Since I started writing this email,
> >>the load on the email server went down from 189 to 8 righ tnow. I
> >>noticed somewhere elase on the internet that there was a similar problem
> >>with 2.0.16. I am running 2.1.12.
> There is an undocumented(?) Cyrus imapd.conf switch:
> foolstupidclients: 1
> ...which converts all 'list "" *' IMAP commands into
> 'list "" INBOX*'. If the user has no mailboxes outside INBOX.*,
> they (or IMP) won't see any difference, but the performance
> impact for Cyrus on Berkeley is dramatic - the former command scans
> situation may start to escalate.
> Apparently IMP, in at least some configurations, does these commands
> quite often even though there is a mailbox prefix setting.
> And as Rob already said, you'd be better off switching to
> skiplist and forgetting this kludge, if at all possible.


Instead of changing anything in the cyrus end, i went to imp's servers.php 
configuration file. There's omething in there for mailbox prefix or 
whathave you, it was set to ''. I changed it to 'INBOX.' and almost 
_immediately_ the load on cyrus started to drop! Within a few minutes it 
was down to 0.78. 

Thanks a lot for your input. I will investigate and move over to skip list 
during the next downtime. 

Once again, thanks for the replies from everyone! We just got a bunch of 
new clients into our server, and it would have looked bad for open source 
if the problems persisted! 

Yay! :-D


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