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Re: EXPLAIN output explanation requested

From: "A(dot) Kretschmer" <andreas(dot)kretschmer(at)schollglas(dot)com>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: EXPLAIN output explanation requested
Date: 2008-06-03 18:24:58
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Lists: pgsql-novice
am  Tue, dem 03.06.2008, um 19:51:05 +0200 mailte Ron Arts folgendes:
> A. Kretschmer schreef:
> >am  Tue, dem 03.06.2008, um 12:35:34 +0200 mailte A. Kretschmer folgendes:
> >>I guess, you have much insert/delete or update - operations on this
> >>table and no recent vacuum.
> >>
> >>Try to run a 'vacuum full;' and re-run your query. And, run a 'explain
> >>analyse <your query>' to see the estimated costs and the real costs. 
> >
> >Btw, run 'select relpages, reltuples from pg_class where relname='phone'; 
> >before and after the 'vacuum full' and show us the result.
> What do those values relpages and reltuples mean?

relpages: number of physical pages for the table on disk (one
page=4 Kbyte)

reltuples: number of tuples for the table

Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID:   0x3FFF606C, privat 0x7F4584DA

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