[Dovecot] dbmail benchmarking

[Justin McAleer]

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.
>
>

Timo, what was the hardware you used for this test?

>
>  - 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).