Re: Remove XLogRecGetFullXid() in xlogreader.c?

(I've added Thomas Munro to the thread.)

On Fri, Jan 17, 2025 at 02:00:49PM +0900, Michael Paquier wrote:
> XLogRecGetFullXid() has been introduced in 67b9b3ca3283 back in 2019,
> but as far as I can see this has never been used in the code and this
> is used nowhere in the core code.
>
> I have looked at Debian's codesearch and also looked at traces of it
> on github without seeing it being used anywhere. Knowing that this
> was originally intended for a hypothetical undo log patch back then,
> for which no work has been done for years, is there any point in
> keeping this function in core?
>
> This issue has been raised on a separate thread, where Noah has sent a
> patch to consolidate a bit some epoch calculations for
> FullTransactionIds, around here:
> https://www.postgresql.org/message-id/Z4i6MbUlZxjK1rRh@paquier.xyz
>
> Removing it would have the benefit to do a bit less refactoring for
> some of the work of the other thread, and this removes all traces of
> -DFRONTEND in xlogreader.h. ;)

Seems reasonable to me. I think the counterargument is that folks
developing new AMs should use this [0], but if no such users have
materialized in several years, then maybe that's no longer a concern.

[0] https://postgr.es/m/CA%2BhUKG%2BmLmuDjMi6o1dxkKvGRL56Y2Rz%2BiXAcrZV03G9ZuFQ8Q%40mail.gmail.com

--
nathan