cyrus-imapd 2.2 db3 or db4?

[Igor Brezac]

On Wed, 7 May 2003, Lawrence Greenfield wrote:

>    Date: Wed, 7 May 2003 10:06:34 -0400 (EDT)
>    From: Rob Siemborski <rjs3 at andrew.cmu.edu>
>
>    > Are there any issues with skiplist and duplicate.db?  db4 (db-4.1.25) on a
>    > busy server doing duplicatesuppression does not do well.  I will test
>    > skiplist on a small server first or I will need to turn
>    > duplicatesuppression off.
>
>    There shouldn't be any reasons against it, no.
>
> Well, performance. Skiplist requires two synchronous writes for every
> modification, and allows only one writer at a time.
>
> Berkeley db uses asynchronously (which is how we keep the duplicate
> delivery database) can do much much better than this.

What sleepycat db version do you use?  Something is broken with the 4.1.25
version on busy sites.  It works fine on small installations.  I can tweak
db env (via DB_CONFIG), but eventually it runs out of resources and
duplicate suppression stops working.  What is the drawback of turning
duplicate suppression off besides diskspace?  My logs show less then .01%
duplicate messages.  Furthermore, chechpoint of a large duplicate.db
(50MB) takes over 10 minutes on my system and high cpu utilization.

-- 
Igor