Date: Thu, 14 Jan 2010 18:30:25 +0100
From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-performance@postgresql.org
Subject: Re: bad execution plan for subselects containing
	windowing-function
Message-ID: <20100114173025.GA8675@tux>
References: <20100114170318.GA7634@tux> <25448.1263489336@sss.pgh.pa.us>
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Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Andreas Kretschmer <akretschmer@spamfence.net> writes:
> > No question, this is a silly query, but the problem is the 2nd query: it
> > is obviously not possible for the planner to put the where-condition
> > into the subquery.
> 
> Well, yeah: it might change the results of the window functions.
> I see no bug here.  Your second query asks for a much more complicated
> computation, it's not surprising it takes longer.

Thank you for the fast answer.

But sorry, I disagree. It is the same query with the same result. I can't see
how the queries should return different results.

What have i overlooked?


tia, Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
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