From: Meetesh Karia <meetesh.karia@gmail.com>
To: Tobias Brox <tobias@nordicbet.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Planner incorrectly choosing seq scan over index scan
Date: Tue, 2 Aug 2005 01:30:26 +0200
Message-ID: <fc5b04ca0508011630e745176@mail.gmail.com> (raw)
In-Reply-To: <20050801223708.GE17649@tobias.lan>
References: <fc5b04ca05080115195d15c456@mail.gmail.com>
<20050801223708.GE17649@tobias.lan>
Are you referring to the statistics gathering target for ANALYZE? Based on
your email, I just tried the following and then re-ran the explain analyze
but got the same "incorrect" plan:
alter table candidates617004
alter column sourceId set statistics 1000,
alter column targetId set statistics 1000;
analyze candidates617004;
alter table lte_user
alter column user_id set statistics 1000;
analyze lte_user;
Thanks for your suggestion,
Meetesh
On 8/2/05, Tobias Brox <tobias@nordicbet.com> wrote:
>
> [Meetesh Karia - Tue at 12:19:27AM +0200]
> > We're using 8.0.3 and we're seeing a problem where the planner is
> choosing a
> > seq scan and hash join over an index scan. If I set enable_hashjoin to
> off,
> > then I get the plan I'm expecting and the query runs a lot faster. I've
> also
> > tried lowering the random page cost (even to 1) but the planner still
> > chooses to use the hash join.
>
> Have you tried increasing the statistics collection?
>
> --
> Tobias Brox, +47-91700050
> Nordicbet, IT dept
>
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To: pgsql-performance@postgresql.org
Cc: meetesh.karia@gmail.com, tobias@nordicbet.com
Subject: Re: Planner incorrectly choosing seq scan over index scan
In-Reply-To: <fc5b04ca0508011630e745176@mail.gmail.com>
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