Message-ID: <49131ED5.80307@archonet.com>
Date: Thu, 06 Nov 2008 16:44:05 +0000
From: Richard Huxton <dev@archonet.com>
User-Agent: Thunderbird 2.0.0.17 (X11/20080914)
MIME-Version: 1.0
To: =?UTF-8?B?0JLRltGC0LDQu9GW0Lkg0KLQuNC80YfQuNGI0LjQvQ==?=
 <tivv00@gmail.com>
CC: pgsql-performance@postgresql.org
Subject: Re: PostgreSQL OR performance
References: <331e40660811050312u552cab53ifa88e493e1c4f7ac@mail.gmail.com>	
	<1225902700.1432.53.camel@jdavis>	
	<331e40660811060246m51df553egd4e2ba91f08d1434@mail.gmail.com>	
	<29e3942f0811060426k5fe34b1av401a2dba62e4ae3c@mail.gmail.com>
	<331e40660811060833l49bf837em41ca88d4b2061ea1@mail.gmail.com>
In-Reply-To: <331e40660811060833l49bf837em41ca88d4b2061ea1@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

=D0=92=D1=96=D1=82=D0=B0=D0=BB=D1=96=D0=B9 =D0=A2=D0=B8=D0=BC=D1=87=D0=B8=
=D1=88=D0=B8=D0=BD wrote:
> As you can see from other plans, it do have all the indexes to perform =
it's
> work fast (when given part by part). It simply do not wish to use them.=
 My
> question: Is this a configuration problem or postgresql optimizer simpl=
y
> can't do such a query rewrite?

I must admit, I haven't managed to figure out what your query is trying
to do, but then that's a common problem with autogenerated queries.

The main question that needs answering is why the planner thinks you're
going to get 1.3 billion rows in the "or" query:

"Nested Loop  (cost=3D4588.13..960900482668.95 rows=3D1386158171 width=3D=
32)"

You don't show "explain analyse" for this query, so there's no way of
knowing how many rows get returned but presumably you're expecting
around 88000. What does "explain analyse" return?

--=20
  Richard Huxton
  Archonet Ltd