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From: Shinya Kato <shinya11.kato@gmail.com>
Date: Mon, 9 Feb 2026 21:07:03 +0900
Message-ID: <CAOzEurTHVoxj=O_QxDsC+wE3Gcyj+5q6Jt-C-VXTZyW939UX5Q@mail.gmail.com>
Subject: Re: Use pg_current_xact_id() instead of deprecated txid_current()
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>, 
	pgsql-hackers <pgsql-hackers@lists.postgresql.org>
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On Mon, Feb 9, 2026 at 1:24=E2=80=AFAM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> =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 rational=
e 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.

Got it. I=E2=80=99ll give it a try, thanks.

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

I agree that casting xid8 to bigint was not the right approach.
However, I still believe it's important to move away from using
deprecated functions.

--=20
Best regards,
Shinya Kato
NTT OSS Center