From: Richard Huxton <dev@archonet.com>
To: Gerardo Herzig <gherzig@fmed.uba.ar>
Cc: pgsql-sql@postgresql.org
Subject: Re: index not being used. Why?
Date: Fri, 09 Mar 2007 15:59:48 +0000
Message-ID: <45F18474.4000207@archonet.com> (raw)
In-Reply-To: <45F176CA.3050107@fmed.uba.ar>
References: <45F176CA.3050107@fmed.uba.ar>
Gerardo Herzig wrote:
> -> Seq Scan on pages (cost=0.00..9.08 rows=408 width=55)
> Watch the last row of the explain command. It makes a sequential scan on
> the pages table, like it is not using the index on the "id" field.
You only have 408 rows in the table - it's probably not worth the
trouble of using an index and *then* fetching the rows. Especially since
it's going to match most of the pages anyway.
Try adding a few thousand rows, analyse and see if it decides to use the
index then.
--
Richard Huxton
Archonet Ltd
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, gherzig@fmed.uba.ar
Subject: Re: index not being used. Why?
In-Reply-To: <45F18474.4000207@archonet.com>
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