Re: performance - self-joins vs. subqueries

From: "K(dot) Ari Krupnikov" <ari(at)iln(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: performance - self-joins vs. subqueries
Date: 2001-02-13 00:43:29
Message-ID: 3A888331.6DF45B27@iln.net
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Tom Lane wrote:
>
> "K. Ari Krupnikov" <ari(at)iln(dot)net> writes:
> > Many queries can be formulated as either a self-join or a subquery on
> > the same table.
> > Is there any difference in performance, or does the analyzer treat them
> > the same?
>
> You're a lot better off with a self-join, at present.

At present - is there a change planned?

Could you elaborate a little on how such queries are expanded?

--
K. Ari Krupnikov

DBDOM - bridging XML and relational databases
http://www.iter.co.il

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