On Tue, Jun 3, 2025 at 1:59 PM Peter Geoghegan <p...@bowt.ie> wrote: > We do currently end up using OldestXmin-1 as our > snapshotConflictHorizon when this happens, but as I said in the other > email, I don't think that that's really required.
Actually, that's not really true, either. That is, it is possible (though probably very rare) for VACUUM to set an xmax Multi > OldestMxact with individual members that are still > OldestXmin, while ultimately being able to set the page all-frozen in the VM. snapshotConflictHorizon would then come from visibility_cutoff_xid -- which might end up being InvalidTransactionId. -- Peter Geoghegan
