Re: PL/pgSQL PERFORM with CTE

From: Merlin Moncure <mmoncure(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: Josh Berkus <josh(at)agliodbs(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jan Wieck <JanWieck(at)yahoo(dot)com>, Andres Freund <andres(at)2ndquadrant(dot)com>, "David E(dot) Wheeler" <david(at)justatheory(dot)com>, pgsql-hackers Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: PL/pgSQL PERFORM with CTE
Date: 2013-08-23 18:43:55
Message-ID: CAHyXU0yxk11Y0Ov=+TKHZmvtuDjA+FaVv1sYctTuD0durddMpg@mail.gmail.com
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On Fri, Aug 23, 2013 at 1:38 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>
>
>
> 2013/8/23 Merlin Moncure <mmoncure(at)gmail(dot)com>
> I think so is not good if some programming language functionality does one
> in one context (functions) and does something else in second context
> (procedures).

It's not really different -- it means 'return if able'. Also there
are a lot of things that would have to be different for other reasons
especially transaction management. It's not reasonable to expect same
behavior in function vs procedure context -- especially in terms of
sending output to the caller.

> On second hand, I am thinking so requirement PERFORM is good. A query that
> does some, but result is ignored, is strange (and it can be a performance
> fault), so we should not be too friendly in this use case.

Completely disagree. There are many cases where this is *not*
strange. For example:
SELECT writing_func(some_col) FROM foo;

merlin

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