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To: Linos <info@linos.es>
cc: pgsql-performance@postgresql.org
Subject: Re: CTE vs Subquery 
In-reply-to: <4EA6E252.6030002@linos.es> 
References: <4EA6E252.6030002@linos.es>
Comments: In-reply-to Linos <info@linos.es>
	message dated "Tue, 25 Oct 2011 18:22:42 +0200"
Date: Tue, 25 Oct 2011 12:43:45 -0400
Message-ID: <24672.1319561025@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Linos <info@linos.es> writes:
>     i am having any problems with performance of queries that uses CTE, can the
> join on a CTE use the index of the original table?

CTEs act as optimization fences.  This is a feature, not a bug.  Use
them when you want to isolate the evaluation of a subquery.

			regards, tom lane