[Dovecot] dbmail benchmarking

Troy Benjegerdes
Mon, 14 May 2007 17:37:50 -0000

Could someone please update the dbmail wikipedia page with this info ;)

http://en.wikipedia.org/wiki/DBMail_IMAP_and_POP3_server

I suppose what would be nicer would be to extend the dovecot entry and
reference that from the dbmail entry ;)

On Sat, May 12, 2007 at 03:16:05AM +0300, Timo Sirainen
wrote:
> I thought I'd try benchmarking with dbmail (v2.2.4) to see how much
> slower a SQL backend could actually be. Skip to bottom for the
> conclusions.
>
> Originally I ran the tests with the databases being in XFS
> filesystem. MySQL's performance was horrible. It went 3-7x faster
> with ext3.
>
> MySQL 5.0.30 backend (innodb):
>
> ./imaptest clients=1 - append=100 seed=1 secs=30 msgs=1000000 logout=0
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    1  291  303
>
> So that's 10 messages/sec saved. Now how about with 5 concurrent
> clients?
>
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    5 1259 1332
>
> Pretty well. Then something more generic:
>
> ./imaptest clients=1 seed=1 secs=30 msgs=1000000 logout=0
> Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100% 100%  50% 100% 100% 100%
>                           30%                  5%
>    1   37   36   75   73  110   34   24   73   78
>
> Without Fetc (header/metadata fetching):
> Logi List Stat Sele Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100%  50% 100% 100% 100%
>                      30%                  5%
>    1   94   94  199  283  102   85  198  210
>
> PostgreSQL 8.1.5 backend:
>
> ./imaptest clients=1 - append=100 seed=1 secs=30 msgs=1000000 logout=0
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    1  267  277
>
> ./imaptest clients=5 - append=100 seed=1 secs=30 msgs=1000000 logout=0
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    5 1094 1144
>
> ./imaptest clients=1 seed=1 secs=30 msgs=1000000 logout=0
> Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100% 100%  50% 100% 100% 100%
>                           30%                  5%
>    9   29   40   74   72   99   22   12   64   71
>
> ./imaptest clients=1 seed=1 secs=30 msgs=1000000 logout=0 fetch=0
> Logi List Stat Sele Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100%  50% 100% 100% 100%
>                      30%                  5%
>   35  105   95  200  277   54   70  165  175
>
> The last two tests gave "Unexpected tagged reply:" errors that I
> didn't get with MySQL. So apparently there's some
PostgreSQL-specific
> bug in dbmail.
>
> The same values with Dovecot 1.0 + maildir:
>
> ./imaptest clients=1 - append=100 seed=1 secs=30 msgs=1000000 logout=0
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    1  346  364
>
> ./imaptest clients=5 - append=100 seed=1 secs=30 msgs=1000000 logout=0
> Logi Sele Appe
> 100% 100% 100%
>             5%
>    5 1408 1470
>
> ./imaptest clients=1 seed=1 secs=30 msgs=1000000 logout=0
> Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100% 100%  50% 100% 100% 100%
>                           30%                  5%
>    1  130  133  259  258  382  123  127  257  271
>
> ./imaptest clients=1 seed=1 secs=30 msgs=1000000 logout=0 fetch=0
> Logi List Stat Sele Fet2 Stor Dele Expu Appe
> 100%  50%  50% 100% 100%  50% 100% 100% 100%
>                      30%                  5%
>    1  155  163  339  478  169  175  338  354
>
> So, what are the conclusions?
>
>  - In raw append speed dbmail is almost as fast as maildir.
>  - In raw read/write speed maildir is about 1,6 times faster
>  - When adding metadata fetches Dovecot is 4 times faster than
> dbmail. This is most likely because dbmail doesn't have a cache
> equivalent to dovecot.index.cache so it has to do the fetches the
> slow way.
>
> I would have liked to also run the generic tests with more than 1
> client, but then I start hitting dbmail bugs and the test stops
> (reported already to their bugtracker).



--
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Troy Benjegerdes                'da hozer'                hozer at
hozed.org

Somone asked me why I work on this free (http://www.fsf.org/philosophy/)
software stuff and not get a real job. Charles Shultz had the best answer:

"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't.
That's why
I draw cartoons. It's my life." -- Charles Shultz