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To: Gerardo Herzig <gherzig@fmed.uba.ar>
cc: postgres list <pgsql-sql@postgresql.org>
Subject: Re: advice on query joining 10 tables 
In-reply-to: <4BE8530C.6030605@fmed.uba.ar> 
References: <4BE8530C.6030605@fmed.uba.ar>
Comments: In-reply-to Gerardo Herzig <gherzig@fmed.uba.ar>
	message dated "Mon, 10 May 2010 15:40:12 -0300"
Date: Mon, 10 May 2010 16:11:25 -0400
Message-ID: <16630.1273522285@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Gerardo Herzig <gherzig@fmed.uba.ar> writes:
> Hi all. Im triyng to see if i can improve the performance of a query
> (mainly a 10 table join)

One easy thing to try is increase from_collapse_limit and/or
join_collapse_limit to 10 or more.  That will result in longer planning
time but might let the planner find a better plan for this query.

			regards, tom lane