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Re: partitioning question 1

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Ben <midfield(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: partitioning question 1
Date: 2010-10-28 20:48:32
Message-ID: 1288298912.22359.46.camel@jd-desktop (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, 2010-10-28 at 12:59 -0700, Ben wrote:
> On Oct 28, 2010, at 12:44 PM, Joshua D. Drake wrote:
> > 
> > My tests show you are incorrect:
> > 
> > 
> > part_test=# explain analyze select * from foo join bar using (i) where
> > i=9;
> >                                                    QUERY
> > PLAN                                                    
> > ------------------------------------------------------------------------------------------------------------------
> > Nested Loop  (cost=34.26..106.76 rows=200 width=20) (actual
> > time=0.004..0.004 rows=0 loops=1)
> >   ->  Append  (cost=0.00..68.50 rows=20 width=12) (actual
> > time=0.004..0.004 rows=0 loops=1)
> >         ->  Seq Scan on foo  (cost=0.00..34.25 rows=10 width=12)
> > (actual time=0.001..0.001 rows=0 loops=1)
> >               Filter: (i = 9)
> >         ->  Seq Scan on foo_1 foo  (cost=0.00..34.25 rows=10 width=12)
> > (actual time=0.000..0.000 rows=0 loops=1)
> >               Filter: (i = 9)
> >   ->  Materialize  (cost=34.26..34.36 rows=10 width=12) (never
> > executed)
> >         ->  Seq Scan on bar  (cost=0.00..34.25 rows=10 width=12) (never
> > executed)
> >               Filter: (i = 9)
> > Total runtime: 0.032 ms
> > (10 rows)
> 
> strange.  my tests don't agree with your tests :

Do you have constraint_exclusion turned on? You should verify with show
constraint_exclusion (I saw what you wrote below).

JD

P.S. Blatant plug, you coming to http://www.postgresqlconference.org ?


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