Re: visibility map corruption

On Tue, Jul 6, 2021 at 06:49:10PM -0400, Bruce Momjian wrote:
> On Tue, Jul 6, 2021 at 03:46:48PM -0700, Peter Geoghegan wrote:
> > On Tue, Jul 6, 2021 at 3:30 PM Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > > Yes, I can, though it seems like a much bigger issue than pg_upgrade.
> > > I will be glad to dig into it.
> >
> > I'm not sure what you mean by that. Technically this would be an issue
> > for any program that uses "pg_resetwal -x" in the way that pg_upgrade
> > does, with those same expectations. But isn't pg_upgrade the only
> > known program that behaves like that?
> >
> > I don't see any reason why this wouldn't be treated as a pg_upgrade
> > bug in the release notes, regardless of the exact nature or provenance
> > of the issue -- the pg_upgrade framing seems useful because this is a
> > practical problem for pg_upgrade users alone. Have I missed something?
>
> My point is that there are a lot internals involved here that are not
> part of pg_upgrade, though it probably only affects pg_upgrade. Anyway,
> Bertrand patch seems to have what I need.

One question is how do we want to handle cases where -x next_xid is used
but -u oldestXid is not used? Compute a value for oldestXid like we did
previously? Throw an error? Leave oldestXid unchanged? I am thinking
the last option.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

If only the physical world exists, free will is an illusion.