Determine whether or not a subdomain record's domain is missing zone files
        (besides the ones we expect) that could invalidate its history.

def subdomain_check_pending(self, subrec, atlasdb_path, cur=None):
        """
        Determine whether or not a subdomain record's domain is missing zone files
        (besides the ones we expect) that could invalidate its history.
        """
        _, _, domain = is_address_subdomain(subrec.get_fqn())
        sql = 'SELECT missing FROM {} WHERE domain = ? ORDER BY parent_zonefile_index DESC LIMIT 1;'.format(self.subdomain_table)
        args = (domain,)

        cursor = None
        if cur is None:
            cursor = self.conn.cursor()
        else:
            cursor= cur

        rows = db_query_execute(cursor, sql, args)
        missing_str = ""
        try:
            rowdata = rows.fetchone()
            assert rowdata
            missing_str = rowdata['missing']
        except:
            pass

        known_missing = [int(i) for i in missing_str.split(',')] if missing_str is not None and len(missing_str) > 0 else []
        num_missing = atlasdb_get_zonefiles_missing_count_by_name(domain, indexes_exclude=known_missing, path=atlasdb_path)
        if num_missing > 0:
            log.debug("Subdomain is missing {} zone files: {}".format(num_missing, subrec))

        return num_missing > 0