On Monday, February 10, 2025 8:03 PM Nisha Moond <nisha.moond...@gmail.com> 
wrote:
> 
> On Sat, Feb 8, 2025 at 12:28 PM Zhijie Hou (Fujitsu) <houzj.f...@fujitsu.com>
> wrote:
> >
> 
> > 3.
> >
> > +                       if (cause & RS_INVAL_HORIZON)
> > +                       {
> > +                               if (!SlotIsLogical(s))
> > +                                       goto invalidation_marked;
> >
> > I am not sure if this logic is correct. Even if the slot would not be
> > invalidated due to RS_INVAL_HORIZON, we should continue to check other
> causes.
> >
> 
> Used goto here since we do not expect RS_INVAL_HORIZON to be combined
> with any other "cause" and to keep the pgHead behavior.
> However, with the bitflag approach, the code should be future-safe, so
> replacing goto in v73 should handle this now.

I think the following logic needs some adjustments.

+                       if (invalidation_cause == RS_INVAL_NONE &&
+                               (possible_causes & RS_INVAL_HORIZON))
+                       {
+                               if (SlotIsLogical(s) &&
+                               /* invalid DB oid signals a shared relation */
+                                       (dboid == InvalidOid || dboid == 
s->data.database) &&
+                                       
TransactionIdIsValid(initial_effective_xmin) &&
+                                       
TransactionIdPrecedesOrEquals(initial_effective_xmin,
+                                                                               
                  snapshotConflictHorizon))
+                                       invalidation_cause = RS_INVAL_HORIZON;
+                               else if 
(TransactionIdIsValid(initial_catalog_effective_xmin) &&
+                                                
TransactionIdPrecedesOrEquals(initial_catalog_effective_xmin,
+                                                                               
                           snapshotConflictHorizon))
+                                       invalidation_cause = RS_INVAL_HORIZON;
+                       }

I think we assign RS_INVAL_HORIZON to invalidation_cause only when the slot is
logical and the dboid is valid, but it is not guaranteed in the second if
condition ("else if (TransactionIdIsValid(initial_catalog_effective_xmin)").

Here is a top-up patch to fix this.

Best Regards,
Hou zj


Attachment: 0001-fix-if-condition.patch
Description: 0001-fix-if-condition.patch

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