Re: BUG #5230: Limit operator slows down - Mailing list pgsql-bugs

From Robert Haas
Subject Re: BUG #5230: Limit operator slows down
Date
Msg-id 603c8f070912031801r2b8b5db5lc53dfb9b5a40f791@mail.gmail.com
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In response to BUG #5230: Limit operator slows down  ("aftab" <akhangd@hotmail.co.uk>)
List pgsql-bugs
On Thu, Dec 3, 2009 at 10:45 AM, aftab khan <akhangd@hotmail.co.uk> wrote:
> This is not exactly the same what I posted yesterday, What I have posted
> today also include EXPLAIN ANALYZE OUTPUT .

[ adding the list back to the CC line ]

It looks like you have a problem very similar to one Laurence Laborde
was complaining about recently on pgsql-performance.  My discussion of
the problem is here:

http://archives.postgresql.org/pgsql-performance/2009-12/msg00022.php

In your case, the reason why the estimates are off is because of the
lack of multi-column statistics, rather than because of the choice of
operator, but the issues are similar.

...Robert

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