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Re: bad selectivity estimates for CASE - Mailing list pgsql-performance

From Tom Lane
Subject Re: bad selectivity estimates for CASE
Date
Msg-id 3032.1231216843@sss.pgh.pa.us
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In response to bad selectivity estimates for CASE  ("Robert Haas" <robertmhaas@gmail.com>)
Responses Re: bad selectivity estimates for CASE  ("Robert Haas" <robertmhaas@gmail.com>)
List pgsql-performance
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"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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