dovecot - Jul 2007 - avoiding getting maildir cur/ folder contents?

Hi,

On my server with many mails in one folder and slow IO, getting the mail
listing in the cur/ folder is becoming a serious bottleneck. Dovecot is
the only thing accessing the mail folders, so would there be any way to
avoid getting a listing all the time?

johannes
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On 18.7.2007, at 19.03, Johannes Berg wrote:
> On my server with many mails in one folder and slow IO, getting the  
> mail
> listing in the cur/ folder is becoming a serious bottleneck.  
> Dovecot is
> the only thing accessing the mail folders, so would there be any  
> way to
> avoid getting a listing all the time?
Well, there are two things:

1) Remove all dirty states from the code, so if Dovecot changes cur/  
it doesn't later try to re-sync the maildir just in case someone else  
had changed it. I actually thought about doing this and adding a  
maildir_dirty_syncs setting, but then I thought if people want  
performance they'll use dbox. :) (Or you could even remove timestamp  
comparing completely to make sure it never reads cur/)

2) If you want to avoid readdir() completely, then dovecot-uidlist  
file needs to be rewritten each time a flag is changed so it would  
always contain up-to-date filenames. That would make it do more writes.

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On Wednesday, July 18 at 06:03 PM, quoth Johannes Berg:
> On my server with many mails in one folder and slow IO, getting the 
> mail listing in the cur/ folder is becoming a serious bottleneck. 
> Dovecot is the only thing accessing the mail folders, so would there 
> be any way to avoid getting a listing all the time?
I don't suppose improving your IO is an option? I find turning on 
dir_hashing in ext3, and mounting my maildirs with noatime, both 
significantly improve my performance without requiring me to buy new 
hardware.

~Kyle
-- 
The fact that we live at the bottom of a deep gravity well, on the 
surface of a gas-covered planet going around a nuclear fireball 90 
million miles away, and think this to be normal, is obviously some 
indication of how skewed our perspective tends to be...
                                                       -- Douglas Adams
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