From: Bruce Momjian <bruce@momjian.us>
To: Benjamin Krajmalnik <kraj@servoyant.com>
Cc: Rajesh Kumar Mallah <mallah.rajesh@gmail.com>
Cc: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: pgsql-performance@postgresql.org
Subject: Re: cpu bound postgresql setup.
Date: Tue, 29 Jun 2010 11:29:18 -0400 (EDT)
Message-ID: <201006291529.o5TFTIn17113@momjian.us> (raw)
In-Reply-To: <F4E6A2751A2823418A21D4A160B68988614660@fletch.stackdump.local>
Benjamin Krajmalnik wrote:
> > -----Original Message-----
> > From: Bruce Momjian [mailto:bruce@momjian.us]
> > Sent: Monday, June 28, 2010 3:45 PM
> > To: Benjamin Krajmalnik
> > Cc: Rajesh Kumar Mallah; Kevin Grittner; pgsql-
> > performance@postgresql.org
> > Subject: Re: [PERFORM] cpu bound postgresql setup.
> >
> > Benjamin Krajmalnik wrote:
> > > Rajesh,
> > >
> > > I had a similar situation a few weeks ago whereby performance all of
> > a
> > > sudden decreased.
> > > The one tunable which resolved the problem in my case was increasing
> > the
> > > number of checkpoint segments.
> > > After increasing them, everything went back to its normal state.
> >
> > Did you get a db server log message suggesting in increasing that
> > setting? I hope so.
> Unfortunately not. The behavior I had was ebbs and flows. On FreeBSD,
> I was seeing a lot of kernel wait states in top. So every few minutes,
> responsiveness of the db was pretty bad. 8.4.4/amd64 on FreeBSD 7.2
Bummer. What is supposed to happen is if you are checkpointing too
frequently ( < 30 seconds), you get the suggestion about increasing
checkpoint_segments. I have not heard of cases where you are not
checkpointing too frequently, and increasing checkpoint_segments helps.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ None of us is going to be here forever. +
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To: pgsql-performance@postgresql.org
Cc: bruce@momjian.us, kraj@servoyant.com, mallah.rajesh@gmail.com, Kevin.Grittner@wicourts.gov
Subject: Re: cpu bound postgresql setup.
In-Reply-To: <201006291529.o5TFTIn17113@momjian.us>
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