code: def subdomain_check_pending(self, subrec, atlasdb_path, cur=None):
          
          _, _, 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
docs: Determine whether or not a subdomain record's domain is missing zone files
          (besides the ones we expect) that could invalidate its history.