Re: performance question - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: performance question
Date
Msg-id Pine.LNX.4.30.0108281431320.699-100000@peter.localdomain
Whole thread Raw
In response to performance question  ("Reinoud van Leeuwen" <reinoud@xs4all.nl>)
List pgsql-hackers
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@gmx.net   http://funkturm.homeip.net/~peter



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