*
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/transam/transam.c,v 1.58 2004/08/22 02:41:57 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/transam/transam.c,v 1.59 2004/08/28 21:58:59 tgl Exp $
  *
  * NOTES
  *       This file contains the high level access-method interface to the
                if (TransactionIdPrecedes(transactionId, RecentXmin))
                        return true;
                parentXid = SubTransGetParent(transactionId);
+               Assert(TransactionIdIsValid(parentXid));
                return TransactionIdDidAbort(parentXid);
        }