Function sub_select

sql/sql_select.cc:24622–24775

*/

enum_nested_loop_state
sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
  int error;
  enum_nested_loop_state rc;
  DBUG_ENTER("sub_select");

  if (join_tab->split_derived_to_update && !end_of_records)
  {
    table_map tab_map= join_tab->split_derived_to_update;
    for (uint i= 0; tab_map; i++, tab_map>>= 1)
    {
      if (tab_map & 1)
        join->map2table[i]->preread_init_done= false;
    }
  }

  /* Restore state if mark_as_null_row() have been called */
  if (join_tab->last_inner)
  {
    JOIN_TAB *last_inner_tab= join_tab->last_inner;
    for (JOIN_TAB  *jt= join_tab; jt <= last_inner_tab; jt++)
      jt->table->null_row= 0;
  }
  else
    join_tab->table->null_row=0;

  if (end_of_records)
  {
    enum_nested_loop_state nls=
      (*join_tab->next_select)(join,join_tab+1,end_of_records);
    DBUG_RETURN(nls);
  }
  join_tab->tracker->r_scans++;

  rc= NESTED_LOOP_OK;

  for (SJ_TMP_TABLE *flush_dups_table= join_tab->flush_weedout_table;
       flush_dups_table;
       flush_dups_table= flush_dups_table->next_flush_table)
  {
    flush_dups_table->sj_weedout_delete_rows();
  }

  if (!join_tab->preread_init_done && join_tab->preread_init())
    DBUG_RETURN(NESTED_LOOP_ERROR);

  if (unlikely(join_tab->rowid_filter))
  {
    if (unlikely(join_tab->need_to_build_rowid_filter))
    {
      if (join_tab->build_range_rowid_filter())
        DBUG_RETURN(NESTED_LOOP_ERROR);
      /*
        We have to check join_tab->rowid_filter again as the above
        function may have cleared it in case of errors.
      */
      if (join_tab->rowid_filter && join_tab->rowid_filter->is_empty())