From: Jan de Visser <jdevisser@digitalfairway.com>
To: pgsql-performance@postgresql.org
Subject: Slow SELECTS after large update cycle
Date: Wed, 15 Mar 2006 14:39:13 -0500
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Hello,

After fixing the hanging problems I reported here earlier (by uninstalling=
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W2K3 SP1), I'm running into another weird one.

After doing a +/- 8hr cycle of updates and inserts (what we call a 'batch')=
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the first 'reporting' type query on tables involved in that write cycle is=
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very slow. As an example, I have a query which according to EXPLAIN ANALYZE=
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takes about 1.1s taking 46s. After this one hit, everything is back to=20
normal, and subsequent executions of the same query are in fact subsecond.=
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Restarting the appserver and pgsql does not make the slowness re-appear, on=
ly=20
running another batch will.

During the 'write'/batch cycle, a large number of rows in various tables ar=
e=20
inserted and subsequently (repeatedly) updated. The reporting type queries=
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after that are basically searches on those tables.

Anybody any ideas?

Thanks,

jan

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Jan de Visser =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 jdevisser@digitalfair=
way.com

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Baruk Khazad! Khazad ai-menu!
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