Re: Does optimizer know about 'constant' expressions?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Philip Warner <pjw(at)rhyme(dot)com(dot)au>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Does optimizer know about 'constant' expressions?
Date: 2000-09-17 18:16:23
Message-ID: 6821.969214583@sss.pgh.pa.us
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Philip Warner <pjw(at)rhyme(dot)com(dot)au> writes:
> It seems that the optimizer does not know about (or calculate values of)
> constant expressions when determining strategy.

Datetime calculations are not considered constant-foldable. See
prior discussions, eg thread "Constant propagation and similar issues"
in pghackers on 11-Sep.

regards, tom lane

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