From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-sql@postgresql.org
Subject: Re: Counting all rows
Date: Sat, 23 Jun 2007 12:38:56 +0200
Message-ID: <20070623103856.GE7307@KanotixBox> (raw)
In-Reply-To: <adf34c300706230315y43ba92daqf0804b7c377ffd29@mail.gmail.com>
References: <adf34c300706230315y43ba92daqf0804b7c377ffd29@mail.gmail.com>
Stefan Arentz <stefan.arentz@gmail.com> schrieb:
> I need to get statistics from a bunch of tables. Simply the number of
> records in them.
>
> The query plan looks like this:
>
> => explain select count(id) from stuff;
> QUERY PLAN
> -------------------------------------------------------------------
> Aggregate (cost=1629.69..1629.70 rows=1 width=8)
> -> Seq Scan on stuff (cost=0.00..1517.75 rows=44775 width=8)
>
> The sequential scan kind of worries me. Is there a better/faster way to do
> this?
Yes.
A "select count(*) from foo;" enforces a seq. scan. Solutions for this
are discussed here: http://www.varlena.com/GeneralBits/120.php
Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect. (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly." (unknow)
Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
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To: pgsql-sql@postgresql.org
Cc: akretschmer@spamfence.net
Subject: Re: Counting all rows
In-Reply-To: <20070623103856.GE7307@KanotixBox>
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