From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: bad selectivity estimates for CASE
Date: Mon, 05 Jan 2009 23:40:43 -0500
Message-ID: <3032.1231216843@sss.pgh.pa.us> (raw)
In-Reply-To: <603c8f070901051915p15b3d6a7jbe6f6fdd178143e@mail.gmail.com>
References: <603c8f070901051915p15b3d6a7jbe6f6fdd178143e@mail.gmail.com>
"Robert Haas" <robertmhaas@gmail.com> writes:
> While looking at a complex query that is being poorly planned by
> PostgreSQL 8.2.9, I discovered that any non-trivial CASE...WHEN
> expression seems to produce a selectivity estimate of 0.005.
If you have an idea for a non-silly estimate, feel free to enlighten
us...
regards, tom lane
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Subject: Re: bad selectivity estimates for CASE
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