Method cleanup

sql/sql_union.cc:2733–2835

bool st_select_lex_unit::cleanup()
{
  bool error= 0;
  DBUG_ENTER("st_select_lex_unit::cleanup");

  if (cleaned)
  {
    DBUG_RETURN(FALSE);
  }
  if (with_element && with_element->is_recursive && union_result &&
      with_element->rec_outer_references)
  {
    select_union_recursive *result= with_element->rec_result;
    if (++result->cleanup_count == with_element->rec_outer_references)
    {
      /*
        Perform cleanup for with_element and for all with elements
        mutually recursive with it.
      */
      cleaned= 1;
      with_element->get_next_mutually_recursive()->spec->cleanup();
    }
    else
    {
      /*
        Just increment by 1 cleanup_count for with_element and
        for all with elements mutually recursive with it.
      */
      With_element *with_elem= with_element;
      while ((with_elem= with_elem->get_next_mutually_recursive()) !=
             with_element)
        if (with_elem->rec_result)
          with_elem->rec_result->cleanup_count++;
      DBUG_RETURN(FALSE);
    }
  }
  columns_are_renamed= false;
  cleaned= 1;

  for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
    error|= sl->cleanup();
     
  if (fake_select_lex)
  {
    error|= fake_select_lex->cleanup();
    /*
      There are two cases when we should clean order items:
      1. UNION with SELECTs which all enclosed into braces
        in this case global_parameters == fake_select_lex
      2. UNION where last SELECT is not enclosed into braces
        in this case global_parameters == 'last select'
      So we should use global_parameters->order_list for
      proper order list clean up.
      Note: global_parameters and fake_select_lex are always
            initialized for UNION
    */
    DBUG_ASSERT(global_parameters());
    if (global_parameters()->order_list.elements)