Fwd: [Dovecot] Very slow select() command on large mailboxes

Timo Sirainen tss at iki.fi
Fri Jul 22 14:36:53 EEST 2005


Dovecot 0.99.x opens all files in maildir when selecting it the first
time, so that's probably why it's slow. 1.0-stable and 1.0-test releases
open the files only when client requests the mails.

On Thu, 2005-07-14 at 15:59 +0200, Sebastjan Trepca wrote:
> Maildir, its easier to export and can support hardlinks. What kind of
> optimizations did you have in mind? What's the downside of mbox? 
> Problem is that version 1.0 is only test release for now.
> 
> 
> On 7/14/05, Timo Sirainen <tss at iki.fi> wrote:
>         On Thu, 2005-07-14 at 11:59 +0200, Sebastjan Trepca wrote:
>         > Hi,
>         >
>         > I'm trying to decide if I could use you mail server in our
>         enviroment
>         > which has about 10k users and mailboxes size about ~1GB. 
>         > So I made a few tests and it all worked quite fast, except
>         that select
>         > command on large mailboxes. The first time I select a
>         mailbox which
>         > has 10k messages it takes about 4s to process. I am
>         deliberately 
>         > trying this on a Celeron 850Mhz, 512 MB memory and some
>         shitty
>         > hard-drive to maximize the times.
>         > So why is this so slow? Does it index the messages on
>         select? It's
>         > even slower when I have some new messages in folder, more
>         that I have 
>         > more I wait. So I presume it must be something with
>         indexing? Anyway,
>         > how could I optimize this? Why don't you index when a mail
>         arrives
>         > instead of on select?
>         
>         mbox or maildir? mbox can be optimized in different ways with 
>         1.0-stable/test releases, but maildir itself needs to be
>         rescanned all
>         too often..
>         
>         
> 
> 
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