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Subject: Re: amount of join's and sequential access to the tables
 involved
From: Gerardo Herzig <gherzig@fmed.uba.ar>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-sql@postgresql.org
In-Reply-To: <20152.1326296428@sss.pgh.pa.us>
References: <1326296192.24629.12.camel@inca.fmed.uba.ar>
	<20152.1326296428@sss.pgh.pa.us>
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Date: Thu, 12 Jan 2012 11:09:55 -0300
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El mi=C3=A9, 11-01-2012 a las 10:40 -0500, Tom Lane escribi=C3=B3:
> Gerardo Herzig <gherzig@fmed.uba.ar> writes:
> > Hi all. Im working on a 'simple' query with 7, 8 left joins. After th=
e
> > 9nth join or so, explain analyze became to show the plan with many
> > tables being read in sequential fashion. Of course, this slows down t=
he
> > query response in a factor on 10.
>=20
> increase join_collapse_limit, perhaps?
>=20
> 			regards, tom lane
>=20

Im sory Tom and all, again stuck with this. Now i have 9 joins, and
join_collapse_limit =3D 20, and the query slows down big time when the 9t=
h
join appears.

Another configuration variable to check against?

Thanks again.
Gerardo