Re: performance question

From: Peter Eisentraut <peter_e(at)gmx(dot)net>
To: Reinoud van Leeuwen <reinoud(at)xs4all(dot)nl>
Cc: <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: performance question
Date: 2001-08-28 12:32:48
Message-ID: Pine.LNX.4.30.0108281431320.699-100000@peter.localdomain
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Reinoud van Leeuwen writes:

> > radius=# select count (radiuspk) from radius ;
> > count
> > --------
> > 398543
> > (1 row)
>
> This query takes about 3 seconds. But the query plan *already* knows the
> number of rows ("rows=398543").

This is only an estimate which is only updated by VACUUM. Presumably you
didn't add or remove any rows since your last VACUUM.

--
Peter Eisentraut peter_e(at)gmx(dot)net http://funkturm.homeip.net/~peter

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