Re: Strange behaviour under heavy load

How to tune them?

Now I have:

checkpoint_segments = 5 # in logfile segments, min 1, 16MB each
checkpoint_timeout = 900 # range 30-3600, in seconds
checkpoint_warning = 30 # in seconds, 0 is off

No checkpoint warnings in pgsql logs.

On 3/27/07, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> wrote:
>
> hmm,
>
> looks like checkpoint ?
> Check checkpoint settings in postgresql.conf.
>
>
> Oleg
> On Tue, 27 Mar 2007, Dmitry Koterov wrote:
>
> > Hello.
> >
> > I have found that sometimes heavy loaded PostgreSQL begins to run all
> the
> > queries slower than usual, sometimes - 5 and more times slower. I cannot
> > reprocude that, but symptoms are the following: queries work very fast
> for
> > 5-10 minutes, and after that - significant slowdown (every query, even a
> > simple one, works 5-10 and ever more times slower), disk write activity
> > grows too (but not everytime - I don't know exactli if there is a direct
> > correlation). 2-3 seconds, then - performance restores back to normal.
> >
> > Autovacuum is turned off.
> >
> > Machine has 2 processors, huge memory, fast SCSI disks.
> >
> > I understand that there is too less information. Please advice what to
> > monitor for better problem discovering.
> >
>
> Regards,
> Oleg
> _____________________________________________________________
> Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru)
> Sternberg Astronomical Institute, Moscow University, Russia
> Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
> phone: +007(495)939-16-83, +007(495)939-23-83
>
> ---------------------------(end of broadcast)---------------------------
> TIP 1: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo(at)postgresql(dot)org so that your
> message can get through to the mailing list cleanly
>