Re: Intermittent buildfarm failures on wrasse

On Wed, Apr 13, 2022 at 6:05 PM Andres Freund <andres@anarazel.de> wrote:
> I think most of those we've ended up replacing by using temp tables in
> those tests instead, since they're not affected by the global horizon
> anymore.

Maybe, but it's a pain to have to work that way. You can't do it in
cases like this, because a temp table is not workable. So that's not
an ideal long term solution.

> > We'd not necessarily have to embed wait-for-horizon into VACUUM
> > itself.
>
> I'm not sure it'd be quite reliable outside of vacuum though, due to the
> horizon potentially going backwards (in otherwise harmless ways)?

I agree, since vacuumlazy.c would need to either be given its own
OldestXmin, or knowledge of a wait-up-to XID. Either way we have to
make non-trivial changes to vacuumlazy.c.

-- 
Peter Geoghegan