Re: BUG #17255: Server crashes in index_delete_sort_cmp() due to race condition with vacuum

On Wed, Nov 10, 2021 at 1:04 PM Peter Geoghegan <pg@bowt.ie> wrote:
> On Wed, Nov 10, 2021 at 11:20 AM Andres Freund <andres@anarazel.de> wrote:
> > The way this definitely breaks - I have been able to reproduce this in
> > isolation - is when one tuple is processed twice by heap_prune_chain(), and
> > the result of HeapTupleSatisfiesVacuum() changes from
> > HEAPTUPLE_DELETE_IN_PROGRESS to DEAD.
>
> I had no idea that that was now possible. I really think that this
> ought to be documented centrally.

BTW, is it just a coincidence that we have only seen these problems
with pg_class? Or does it have something to do with the specifics of
VISHORIZON_CATALOG/horizons.catalog_oldest_nonremovable, or something
else along those lines?

-- 
Peter Geoghegan