On Tue, Nov 15, 2022 at 3:32 AM Andres Freund <and...@anarazel.de> wrote:
> > > Furthermore, it is > > possible that successor[x] = successor[x'] since the page might be > corrupted > > and we haven't checked otherwise. > > > > predecessor[y] = x means that successor[x] = y but in addition we've > > checked that y is sane, and that x.xmax=y.xmin. If there are multiple > > tuples for which these conditions hold, we've issued complaints about > > all but one and entered the last into the predecessor array. > > As shown by the isolationtester test I just posted, this doesn't quite work > right now. Probably fixable. > > I don't think we can follow non-HOT ctid chains if they're older than the > xmin > horizon, including all cases of xmin being frozen. There's just nothing > guaranteeing that the tuples are actually "related". > > I understand the problem with frozen tuples but don't understand the concern with non-HOT chains, could you please help with some explanation around it? -- Regards, Himanshu Upadhyaya EnterpriseDB: http://www.enterprisedb.com
