On Wed, Nov 16, 2022 at 1:58 AM Robert Haas <robertmh...@gmail.com> wrote:
> On Tue, Nov 15, 2022 at 2:50 PM Andres Freund <and...@anarazel.de> wrote: > > 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). > > Woops, you're right. yes, got it, have tried to test and it is giving false corruption in case of subtransaction. I think a better way to have this check is, we need to check that if pred_xmin is aborted then current_xmin should be aborted only. So there is no way that we validate corruption with in_progress txid. -- Regards, Himanshu Upadhyaya EnterpriseDB: http://www.enterprisedb.com
