Re: disk performance benchmarks

On Wed, Sep 15, 2004 at 11:36:18AM -0700, Jeffrey W. Baker wrote:
> On Wed, 2004-09-15 at 10:53, Vivek Khera wrote:
> > >>>>> "JWB" == Jeffrey W Baker <jwbaker(at)acm(dot)org> writes:
> >
> > JWB> All these replies are really interesting, but the point is not that my
> > JWB> RAIDs are too slow, or that my CPUs are too slow. My point is that, for
> > JWB> long stretches of time, by database doesn't come anywhere near using the
> > JWB> capacity of the hardware. And I think that's odd and would like to
> > JWB> config it to "false".
> >
> > Have you tried to increase your checkpoing_segments? I get the
> > suspicion that you're checkpointing every 3 minutes constantly.
> > You'll have to restart the postmaster for this setting to take effect,
> > I believe.
>
> I have checkpoint_segments set to 24, but I get the feeling that making
> it larger may have the opposite effect of what I want, by extending the
> period during which the DB makes no progress.

It sounds strange that the DB stops doing anything while the checkpoint
is in progress. Have you tried poking at pg_locks during that interval?

--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
"La naturaleza, tan frágil, tan expuesta a la muerte... y tan viva"