Message-ID: <33ae625c9ec9072ac61708405c2e7dfe50097047.camel@j-davis.com>
Subject: Re: BUG #18965: Issue with Short-Circuit Evaluation in Boolean
 Expressions
From: Jeff Davis <pgsql@j-davis.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>,
 "brandystodd@gmail.com" <brandystodd@gmail.com>,
 "pgsql-bugs@lists.postgresql.org" <pgsql-bugs@lists.postgresql.org>
Date: Tue, 08 Jul 2025 10:34:23 -0700
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 <CAKFQuwZ6qgcGCXDEHBMftRvC=qmEbh_LT-J=jU96Y2c1V3k0QA@mail.gmail.com>
References: <18965-89456ea7e640a053@postgresql.org>
	 <CAKFQuwZ6qgcGCXDEHBMftRvC=qmEbh_LT-J=jU96Y2c1V3k0QA@mail.gmail.com>
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On Fri, 2025-06-20 at 11:14 -0700, David G. Johnston wrote:
> > In the circumstance where a function evaluation is performed within
> > Boolean
> > expression, the evaluation seems to continue past a function
> > returning a
> > TRUE value.
> >=20
>=20
> Where did we claim we perform short-circuiting?

Even if you force the execution-time evaluation order with CASE, you
can still get an error:

EXPLAIN SELECT CASE WHEN random() < 2 THEN TRUE ELSE (1/0 =3D 0) END;
ERROR:  division by zero

The expression "random() < 2" is always true, so at execution time the
second branch will never be reached. But it is reached at planning
time.

Regards,
	Jeff Davis