Re: Use pg_current_xact_id() instead of deprecated txid_current()

On Mon, Feb 9, 2026 at 1:24 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre(at)kurilemu(dot)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.

Got it. I’ll 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.

--
Best regards,
Shinya Kato
NTT OSS Center