On Thu, 2 Jan 2025 at 01:12, Heikki Linnakangas <hlinn...@iki.fi> wrote:
> > It might be best to just refuse the upgrade if oldestOffsetKnown==false. > It's a very ancient corner case. It seems reasonable to require you to > upgrade to a newer minor version and run VACUUM before upgrading. IIRC > that sets oldestOffsetKnown. > I agree. After all, we do already have a ready-made solution in the form of a vacuum, do we? If I understand all this multixact_old.c machinery correctly, in case of oldestOffsetKnown==false we should fail with "could not open file" or offset will be 0 in GetOldMultiXactIdSingleMember. So, I suppose we can put an analogue of SimpleLruDoesPhysicalPageExist call in the beginning of GetOldMultiXactIdSingleMember. And if either SimpleLruDoesPhysicalPageExist return false or a corresponding offset will be 0 we have to bail out with "oldest offset does not exist, consider running vacuum before pg_upgrdade" or smth. Please, correct me if I'm wrong. -- Best regards, Maxim Orlov.
