Hi, On 2022-11-15 11:36:21 -0500, Robert Haas wrote: > On Mon, Nov 14, 2022 at 5:02 PM Andres Freund <and...@anarazel.de> wrote: > > It seems like we should do a bit more validation within a chain of > > tuples. E.g. that no live tuple can follow an !DidCommit xmin? > > I think this check is already present in stronger form. If we see a > !DidCommit xmin, the xmin of the next tuple in the chain not only can't be > committed, but had better be the same.
As I think I mentioned before, I don't think the "better be the same" aspect is correct, think subxacts. E.g. off 0: xmin: top, xmax: child_1 off 1: xmin: child_1, xmax: invalid If top hasn't committed yet, the current logic afaict will warn about this situation, no? And I don't think we can generally the subxid parent at this point, unfortunately (might have truncated subtrans). Different aspect: Is it ok that we use TransactionIdDidCommit() without a preceding IsInProgress() check? I do think there's some potential for additional checks that don't run into the above issue, e.g. checking that no in-progress xids follow an explicitly aborted xact, that a committed xid can't follow an uncommitted xid etc. Greetings, Andres Freund