From: Faludi Gábor <gfaludi@fits.hu>
To: pgsql-performance@postgresql.org
Subject: how does pg handle concurrent queries and same queries
Date: Mon, 28 Jul 2008 08:43:51 +0200
Message-ID: <000301c8f07d$4bee0f10$e3ca2d30$@hu> (raw)
Hi All,
I have taken over the maintenance of a server farm , recently. 2 webserver
on db server. They are quite powerful 2 processor xeon w/ 6Gig of ram .
Couple of days ago we had a serious performance hit and the db server (pg.
v7.4) was overloaded w/ something in a way that operating system was almost
not able to respond or in cases it did not.
After some analysis i suspect that there is a query that takes up to 1
second and that is the cause. Upon each page loading this query fires and
takes the one second and blocks the page to load completly . The load was
roughly ~300 connections in one minute .
So here are my questions :
. Why does the second and the later queries take the whole on second
if the dataset is the same . Shouldn't PG realise that the query is the same
so i give the user the same resultset ?
. How do I know if one query blocks the other ?
. Is there a way to log the long running queries in 7.4 ? If not is
it available in any newer version ?
thanks for your help !
Üdvözlettel/kind regards,
Faludi, Gábor
FITS Magyarország Kft.
<http://www.fits.hu/; http://www.FITS.hu
Tel.:+36 30 4945862
Email: <mailto:falu@fits.hu> falu@fits.hu
Ingyenes videó tanfolyamok(Excel,Access,Word) :
<http://www.fits.hu/trainings; http://www.fits.hu/trainings
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To: pgsql-performance@postgresql.org
Cc: gfaludi@fits.hu
Subject: Re: how does pg handle concurrent queries and same queries
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