On Wed, Oct 06, 2004 at 01:27:26PM -0400, Alvaro Herrera wrote:
> On Wed, Oct 06, 2004 at 10:01:42AM -0700, Mark Wong wrote:
> > On Mon, Oct 04, 2004 at 02:42:43PM -0400, Greg Stark wrote:
> > > Mark Wong <markw@osdl.org> writes:
> > >
> > > > Links to results are here:
> > > > 7.5devel - http://www.osdl.org/projects/dbt2dev/results/dev4-010/128/
> > > > 8.0beta3 - http://www.osdl.org/projects/dbt2dev/results/dev4-010/180/
> > >
> > > Are those cyclic spikes an artifact of the load of the tests? Or are they
> > > artifacts of the postgres checkpoint process?
> >
> > In the past, they have been artifacts of the checkpoint process. They
> > do smooth out as I increase the checkpoint segments and the timeout.
> > Although I know that doesn't exactly exclude other explanations.
>
> Another knob to test would be bgwriter parameters, say bgwriter_percent
> to maybe 5 or 10. That should distribute more evenly the load.
>
> http://archives.postgresql.org/pgsql-hackers/2004-09/msg00623.php
>
Cool, I increased bgwriter_percent from the default to 10, and that
certainly smoothed things out:http://www.osdl.org/projects/dbt2dev/results/dev4-010/182/
The overall throughput didn't really improved though. :(
Mark