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Re: REPOST: Nested loops row estimates always too high

From: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>
To: Carlo Stonebanks <stonec(dot)register(at)sympatico(dot)ca>
Cc: 'Ow Mun Heng' <Ow(dot)Mun(dot)Heng(at)wdc(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: REPOST: Nested loops row estimates always too high
Date: 2007-09-25 09:31:33
Message-ID: 20070925093133.GA27052@uio.no (view raw or flat)
Thread:
Lists: pgsql-performance
On Tue, Sep 25, 2007 at 12:53:55AM -0400, Carlo Stonebanks wrote:
> My problem is that I think that SRF's are causing my problems. The SRF's
> gets an automatic row estimate of 1000 rows. Add a condition to it, the
> planner guesses 333 rows. Even at 333, this is an overestimate of the number
> of rows returned.
> 
> I'm really disappointed - SRF's are a great way to place the enterprise's
> db-centric business logic at the server.

Fortunately, in 8.3 you can attach a row estimate to the function yourself,
which should most likely fix your problem. Look forward to the first beta :-)

/* Steinar */
-- 
Homepage: http://www.sesse.net/

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