[Dovecot] RC16 is a lot slower that RC7

[Marc Perkel]

Odhiambo WASHINGTON wrote:
> * On 10/01/07 18:56 -0800, Marc Perkel wrote:
> | I tried RC16 from RC7 and like other releases since RC7 it is 
> | significantly slower. I'm still trying to figure out why. But I have 
> | again switched back. Do new version take up a lot more ram perhaps? I'm 
> | running with a gig of ram, and I'm running a few other apps. It's not a 
> | fast computer, just an old 754 pin semptron. But the point is that RC7 
> | runs a lot faster than RC16.
>
> And perhaps even rc17 runs a lot slower that RC7 too, which means you'll
> never upgrade ;)
>
> Could you please give details of how you setup the test environment and
> the figures? I'd like to try and do the same and see what the difference
> in performance is.
>
>
>   

I would like to upgrade but it's on a computer that's somewhat on the 
week side. If I upgrade the computer the problem will probably go away, 
but this setup exposes a possible issue with Dovecot.

I don't have a lot of hard numbers to give you. It's a Semptron bax with 
1 gig of ram and a couple 300 gb SATA drives. Running FC6 32 bit. The 
drives have a raid 1 partition for MBOX email and the indexes are 
separate on a different partiotion that is not a raid partition.

Running mostly dovecot with Exim for the MTA. No spam filtering on this 
box as that is handles on other servers. Inbound traffic is fairly light 
as it receives only good email but for about 250 domains. So most of the 
load is IMAP and POP users.

With RC7 the load levels are low. Right now running about 0.68 according 
to top. With RC16 it would sometimes get that low but would often be 
more around 5.0 or so.

Also running mailman on the server an occasionally when someone runs a 
big list load levels go to 50 but with RC7 the performance is still 
reasonable good under this load where with RC16 it really slows down.

The delays are most noticable when deleting messages and clicking on a 
new folder that has new messages. The delays aren't consistent. 
Sometimes RC16 runs just as fast as RC7. But RC7 is consistently fast.

Wish I have better information to give you to help track it down. Any 
tests you recommend?