Re: dbt-2 tuning results with postgresql-8.3.5

On Mon, Dec 22, 2008 at 7:27 AM, Kevin Grittner
<Kevin.Grittner@wicourts.gov> wrote:
>>>> "Mark Wong" <markwkm@gmail.com> wrote:
>
>> The DL380 G5 is an 8 core Xeon E5405 with 32GB of
>> memory.  The MSA70 is a 25-disk 15,000 RPM SAS array, currently
>> configured as a 25-disk RAID-0 array.
>
>> number of connections (250):
>
>> Moving forward, what other parameters (or combinations of) do people
>> feel would be valuable to illustrate with this workload?
>
> To configure PostgreSQL for OLTP on that hardware, I would strongly
> recommend the use of a connection pool which queues requests above
> some limit on concurrent queries.  My guess is that you'll see best
> results with a limit somewhere aound 40, based on my tests indicating
> that performance drops off above (cpucount * 2) + spindlecount.

It appears to peak around 220 database connections:

http://pugs.postgresql.org/node/514

Of course the system still isn't really tuned all that much...  I
wouldn't be surprised if the workload peaked at a different number of
connections as it is tuned more.

> I wouldn't consider tests of the other parameters as being very useful
> before tuning this.  This is more or less equivalent to the "engines"
> configuration in Sybase, for example.

Regards,
Mark