From: Tom Lane <tgl@sss.pgh.pa.us>
To: Joe Conway <mail@joeconway.com>
cc: Bruce Momjian <bruce@momjian.us>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: PG 14 release notes, first draft
In-reply-to: <30b83e29-76c7-d925-b517-26c530204630@joeconway.com>
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Comments: In-reply-to Joe Conway <mail@joeconway.com>
	message dated "Tue, 11 May 2021 15:18:29 -0400"
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Date: Tue, 11 May 2021 15:51:39 -0400
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Joe Conway <mail@joeconway.com> writes:
> On 5/11/21 1:30 PM, Bruce Momjian wrote:
>> It just feels like this change makes the function's behavior less
>> consistent.

> See Tom's commit message here:
> https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=3d0f68dd30612

> In particular:

>    "The variants of these functions that take
>     numeric inputs (OIDs or column numbers) are
>     supposed to return NULL rather than failing
>     on bad input; this rule reduces problems with
>     snapshot skew when queries apply the functions
>     to all rows of a catalog."

Yeah, the null-return-for-bad-numeric-input behavior is important.
Perhaps a case could be made for returning null for bad text
input too, but I don't recall that anybody has asked for that.

A case could also be made that changing the behavior on the text
side would break applications that expect the current behavior.
So I'm disinclined to make a wholesale change there, without more
evidence that it's a good idea.

			regards, tom lane