Fix HeapTupleSatisfiesVacuum on aborted updater xacts

By using only the macro that checks infomask bits
HEAP_XMAX_IS_LOCKED_ONLY to verify whether a multixact is not an
updater, and not the full HeapTupleHeaderIsOnlyLocked, it would come to
the wrong result in case of a multixact containing an aborted update;
therefore returning the wrong result code.  This would cause predicate.c
to break completely (as in bug report #8273 from David Leverton), and
certain index builds would misbehave.  As far as I can tell, other
callers of the bogus routine would make harmless mistakes or not be
affected by the difference at all; so this was a pretty narrow case.

Also, no other user of the HEAP_XMAX_IS_LOCKED_ONLY macro is as
careless; they all check specifically for the HEAP_XMAX_IS_MULTI case,
and they all verify whether the updater is InvalidXid before concluding
that it's a valid updater.  So there doesn't seem to be any similar bug.

diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c
index 55563ea335d8deaf505084d50b9f18180d3e1de5..c69ffd306ed2cc6978857d77ef24292b26593ea1 100644 (file)
--- a/src/backend/utils/time/tqual.c
+++ b/src/backend/utils/time/tqual.c
@@ -1287,7 +1287,9 @@ HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin,
                {
                        if (tuple->t_infomask & HEAP_XMAX_INVALID)      /* xid invalid */
                                return HEAPTUPLE_INSERT_IN_PROGRESS;
-                       if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask))
+                       /* only locked? run infomask-only check first, for performance */
+                       if (HEAP_XMAX_IS_LOCKED_ONLY(tuple->t_infomask) ||
+                               HeapTupleHeaderIsOnlyLocked(tuple))
                                return HEAPTUPLE_INSERT_IN_PROGRESS;
                        /* inserted and then deleted by same xact */
                        return HEAPTUPLE_DELETE_IN_PROGRESS;