Re: amount of join's and sequential access to the tables involved

From: Gerardo Herzig <gherzig(at)fmed(dot)uba(dot)ar>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: amount of join's and sequential access to the tables involved
Date: 2012-01-12 14:09:55
Message-ID: 1326377395.1877.1.camel@inca.fmed.uba.ar
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-sql

El mié, 11-01-2012 a las 10:40 -0500, Tom Lane escribió:
> Gerardo Herzig <gherzig(at)fmed(dot)uba(dot)ar> writes:
> > Hi all. Im working on a 'simple' query with 7, 8 left joins. After the
> > 9nth join or so, explain analyze became to show the plan with many
> > tables being read in sequential fashion. Of course, this slows down the
> > query response in a factor on 10.
>
> increase join_collapse_limit, perhaps?
>
> regards, tom lane
>

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

Another configuration variable to check against?

Thanks again.
Gerardo

In response to

Browse pgsql-sql by date

  From Date Subject
Next Message Carlos Mennens 2012-01-12 16:42:59 Unable To Modify Table
Previous Message David Johnston 2012-01-12 01:21:25 Re: Unable To Alter Data Type