Re: API stability [was: pgsql: Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.]

On Fri, Apr 8, 2022 at 11:50 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, Apr 8, 2022 at 4:47 AM Markus Wanner
> <markus(dot)wanner(at)enterprisedb(dot)com> wrote:
> > I agree with Michael, it would be nice to not duplicate the code, but
> > use a common underlying method. A modified patch is attached.
>
> I don't think this is better, but I don't think it's worth arguing
> about, either, so I'll do it this way if nobody objects.
>
> Meanwhile, I've committed the patch for master to master.

Well, I've just realized that Kyotaro Horiguchi volunteered to fix
this on an email thread I did not see because of the way Gmail breaks
the thread if you change the subject line. And he developed a very
similar patch to what we have here. I'm going to use this one as the
basis for going forward because I've already studied it in detail and
it's less work for me to stick with what I know than to go study
something else. But, he also noticed something which we didn't notice
here, which is that before v13, the commit in question actually
changed the size of PGXACT, which is really quite bad -- it needs to
be 12 bytes for performance reasons. And there's no spare bytes
available, so I think we should follow one of the suggestions that he
had over in that email thread, and put delayChkptEnd in PGPROC even
though delayChkpt is in PGXACT.

Comments?

--
Robert Haas
EDB: http://www.enterprisedb.com