From: Bruno Wolff III <bruno@wolff.to>
To: Andreas Kretschmer <akretschmer@despammed.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: [despammed] question about index
Date: Thu, 16 Dec 2004 08:10:25 -0600
Message-ID: <20041216141025.GC2768@wolff.to> (raw)
In-Reply-To: <20041216110139.GA5899@Pinguin.wug-glas.de>
References: <20041216104154.GA30578@mail.librelogiciel.com>
<20041216110139.GA5899@Pinguin.wug-glas.de>
On Thu, Dec 16, 2004 at 12:01:39 +0100,
Andreas Kretschmer <akretschmer@despammed.com> wrote:
> >
> > considering that almost 70% of the rows will be with 'VALUE1', 20%
> > will be with 'VALUE2' and 10% will be with 'VALUE3' on the average.
> >
> > should I create an index to speedup the counts or not ?
>
> Yes.
Indexes will probably not help in this case. Even when looking at 10% of
the rows, a sequential scan is still going to be faster than an index
scan in most cases.
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To: pgsql-sql@postgresql.org
Cc: bruno@wolff.to, akretschmer@despammed.com
Subject: Re: [despammed] question about index
In-Reply-To: <20041216141025.GC2768@wolff.to>
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