Re: possible de-optimization of multi-column index plans in 8.3

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: josh(at)agliodbs(dot)com
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: possible de-optimization of multi-column index plans in 8.3
Date: 2007-03-13 00:44:10
Message-ID: 15878.1173746650@sss.pgh.pa.us
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Josh Berkus <josh(at)agliodbs(dot)com> writes:
> One of the Sun benchmarking guys ran across this issue, using a fairly
> recent (within the last 4 weeks) 8.3 snapshot. It appears to me that the
> 8.3 planner is unable to tell that, if the value for the first column of
> an index scan is a constant, the second column doesn't need to be sorted.

Works for me. Care to provide a self-contained test case?

regards, tom lane

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