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: Wed, 11 Jan 2012 13:06:34 -0300
Message-ID: <1326297994.28802.6.camel@inca.fmed.uba.ar>
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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

Crap, yes. That was it.
Just curious about one thing:

That query is part of a function. If i raise set_join_collapse in a psql
bash session, and then excecute the function, there is no changes. But
if i excecute the query directly in the psql session, it flys.

So, what happens, when a plsql function is excecuted, it takes is own
enviroment variables, or something like that?

Thanks again, Tom!

Gerardo