Re: Optimizer's issue

From: Vlad Arkhipov <arhipov(at)dc(dot)baikal(dot)ru>
To: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Optimizer's issue
Date: 2008-04-24 09:47:37
Message-ID: 48105739.30900@dc.baikal.ru
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Albe Laurenz пишет:
> Vlad Arkhipov wrote:
>
>> I found strange issue in very simple query.
>>
>
> You forgot to mention what your problem is.
>
> Yours,
> Laurenz Albe
>
It was written below in my first post:
"These queries are part of big query and optimizer put them on the leaf
of query tree, so rows miscount causes a real problem. "
actual rows count for the first query is 294, estimate - 11; for the
second -- 283 and 0. Postgres tries to use nested loops when it should
use merge/hash join and vice versa.

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