From: | Faludi Gábor <gfaludi(at)fits(dot)hu> |
---|---|
To: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | how does pg handle concurrent queries and same queries |
Date: | 2008-07-28 06:43:51 |
Message-ID: | 000301c8f07d$4bee0f10$e3ca2d30$@hu |
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Thread: | |
Lists: | pgsql-performance |
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(at)fits(dot)hu> falu(at)fits(dot)hu
Ingyenes videó tanfolyamok(Excel,Access,Word) :
<http://www.fits.hu/trainings> http://www.fits.hu/trainings
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