Re: Optimizer & boolean syntax

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Daniele Orlandi <daniele(at)orlandi(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Optimizer & boolean syntax
Date: 2002-11-22 02:50:55
Message-ID: 19807.1037933455@sss.pgh.pa.us
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Daniele Orlandi <daniele(at)orlandi(dot)com> writes:
> The problem is the opposite... so, effectively, seems that the optimizer
> considers "monitored" and "monitored=true" as two different expressions...

Check.

> The viceversa is analog and we also can see that the syntax "monitored
> is true" is considered different from the other two syntaxes:

As it should be.

> What I propose is that all those syntaxes are made equivalent

Only two of them are logically equivalent. Consider NULL.

Even for the first two, assuming equivalence requires hard-wiring an
assumption about the behavior of the "bool = bool" operator; which is
a user-redefinable operator. I'm not totally comfortable with the idea.

regards, tom lane

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