From: Tom Lane <tgl@sss.pgh.pa.us>
To: Clemens Eisserer <linuxhippy@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: hash semi join caused by "IN (select ...)"
Date: Mon, 16 May 2011 19:22:48 -0400
Message-ID: <23922.1305588168@sss.pgh.pa.us> (raw)
In-Reply-To: <BANLkTikR6ngJS9=e1e1yA+E0FyxuJY_i3A@mail.gmail.com>
References: <BANLkTikR6ngJS9=e1e1yA+E0FyxuJY_i3A@mail.gmail.com>
Clemens Eisserer <linuxhippy@gmail.com> writes:
> I have a quite complex, performance sensitive query in a system with a
> few (7) joins:
> select .... from t1 left join t2 .... WHERE id IN (select ....)
Does it work as expected with one less join? If so, try increasing
join_collapse_limit ...
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, linuxhippy@gmail.com
Subject: Re: hash semi join caused by "IN (select ...)"
In-Reply-To: <23922.1305588168@sss.pgh.pa.us>
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