Erwin Lubbers wrote:
> Hi,
> 
> I'm wondering why my dbmail (2.2.13) installation is performing so slow on 
> imap search and sort operations. We're using a 64 Gb/SAS MySQL server 
> dedicated to dbmail as storage (around 300 Gb in use) and serveral 4 Gb 
> machines for the dbmail-imap processes.
> 
> I did try a session by telneting to port 143 and than the following happens:
> 
> ... LOGIN "username" "password"
> 
> Dbmail responsed immediatly with it's OK. Then:
> 
> ... SELECT "INBOX"
> 
> And again it tells within an eyeblink that there are 1039 messages in the 
> INBOX. Then:
> 
> ... SEARCH ALL UNDELETED

That one should really be very fast.

> 
> This response takes 56.3 seconds (!) for those 1039 messages. And a
> 
> ... SORT (DATE) US-ASCII ALL UNDELETED
> 
> took 38.6 seconds.

This one is taking too long on my server. Mostly query-bound time.

> 
> In this time there seems to be no query running on the MySQL server (or it 
> must run for a very short time so my 1 second updates with mysqladmin doesn't 
> seem to catch it).

That is too weird. Normally slow response is an indication of a poorly
performing query. Did the process involved take up a lot of CPU? Try
running vmstat while your running these commands.

> 
> Anyone an idea how to improve the performance?

Setup dbmail.conf to log slow queries, and use 'explain' to locate
missing of poorly configured indexes. And post back your findings.


-- 
  ________________________________________________________________
  Paul Stevens                                      paul at nfg.nl
  NET FACILITIES GROUP                     GPG/PGP: 1024D/11F8CD31
  The Netherlands________________________________http://www.nfg.nl
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