  void next_part_top(ha_rows rownum)
  {
    for (ha_rows i= 0; i < n_rows; i++)
    {
      if (cursor.fetch())
        break;
      remove_value_from_items();
      if (cursor.next())
        at_partition_end= true;
    }
  }
  void next_part_top(ha_rows rownum)
  {
    for (ha_rows i= 0; i < n_rows; i++)
    {
      if (cursor.fetch())
        break;
      remove_value_from_items();
      if (cursor.next())
        at_partition_end= true;
    }
  }