From: | Andreas Kretschmer <akretschmer(at)spamfence(dot)net> |
---|---|
To: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: bad execution plan for subselects containing windowing-function |
Date: | 2010-01-14 17:30:25 |
Message-ID: | 20100114173025.GA8675@tux |
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Lists: | pgsql-performance |
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Andreas Kretschmer <akretschmer(at)spamfence(dot)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)
"If I was god, I would recompile penguin with --enable-fly." (unknown)
Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
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