From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mindaugas Riauba <mind@bi.lt>
Cc: pgsql-performance@postgresql.org
Subject: Re: PostgreSQL strugling during high load
Date: Fri, 13 May 2005 10:12:41 -0400
Message-ID: <23517.1115993561@sss.pgh.pa.us> (raw)
In-Reply-To: <022901c557c5$73df1220$f20214ac@bite.lt>
References: <01cc01c557ba$a4fdb0b0$f20214ac@bite.lt>
<23217.1115991763@sss.pgh.pa.us>
<022901c557c5$73df1220$f20214ac@bite.lt>
"Mindaugas Riauba" <mind@bi.lt> writes:
> It looks like that not only vacuum causes our problems. vacuum_cost
> seems to lower vacuum impact but we are still noticing slow queries "storm".
> We are logging queries that takes >2000ms to process.
> And there is quiet periods and then suddenly 30+ slow queries appears in
> log within the same second. What else could cause such behaviour?
Checkpoints? You should ensure that the checkpoint settings are such
that checkpoints don't happen too often (certainly not oftener than
every five minutes or so), and make sure the bgwriter is configured
to dribble out dirty pages at a reasonable rate, so that the next
checkpoint doesn't have a whole load of stuff to write.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, mind@bi.lt
Subject: Re: PostgreSQL strugling during high load
In-Reply-To: <23517.1115993561@sss.pgh.pa.us>
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