From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>
cc: "Shinya Kato" <shinya11.kato@gmail.com>,
        pgsql-hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Use pg_current_xact_id() instead of deprecated txid_current()
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Comments: In-reply-to =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>
	message dated "Sun, 08 Feb 2026 11:50:24 +0100"
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Date: Sun, 08 Feb 2026 11:24:44 -0500
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=3D?UTF-8?Q?=3DC3=3D81lvaro_Herrera?=3D <alvherre@kurilemu.de> writes:
> On 2026-02-08, Shinya Kato wrote:
>> Since pg_current_xact_id() returns xid8 which does not support
>> arithmetic operators, places that need "xid + 1" cast the result via
>> ::text::bigint first.

> I think it may be better to add some operators, or was there a rationale=
 for these not being there?

I'm fairly concerned about overloading the arithmetic operators with
unsigned versions.  The reason we never invented SQL-level uint8 and
such is fear of getting a lot of "ambiguous operator" errors.  Now,
if we are careful not to create implicit casts between xid[8] and
any ordinary type, maybe it'd be okay to invent xid+int, xid8-int,
and a few more.

As things stand, I don't find the proposed patch to be an improvement.

			regards, tom lane