Function find_unit_handler_for_lex

sql/sql_union.cc:1297–1334

@brief Recursive subroutine to be called from find_unit_handler() (see below). Must not be called directly, only from find_unit_handler(). */

    Must not be called directly, only from find_unit_handler().
*/
static select_handler *find_unit_handler_for_lex(THD *thd,
                                                 SELECT_LEX *sel_lex,
                                                 SELECT_LEX_UNIT* unit)
{
  if (!(sel_lex->join))
    return nullptr;
  for (TABLE_LIST *tbl= sel_lex->join->tables_list; tbl; tbl= tbl->next_local)
  {
    if (!tbl->table)
      continue;
    if (tbl->derived)
    {
      /*
        Skip derived table for now as they will be checked
        in the subsequent loop
      */
      continue;
    }
    handlerton *ht= tbl->table->file->partition_ht();
    if (!ht->create_unit)
      continue;
    select_handler *sh= ht->create_unit(thd, unit);
    if (sh)
      return sh;
  }

  for (SELECT_LEX_UNIT *un= sel_lex->first_inner_unit(); un;
       un= un->next_unit())
  {
    for (SELECT_LEX *sl= un->first_select(); sl; sl= sl->next_select())
    {
      select_handler *uh= find_unit_handler_for_lex(thd, sl, unit);
      if (uh)
        return uh;
    }
  }
  return nullptr;
}


/**