Function set_limit_for_unit

sql/sql_select.cc:34497–34522

*/

static bool set_limit_for_unit(THD *thd, SELECT_LEX_UNIT *unit, ha_rows lim)
{
  SELECT_LEX *gpar= unit->global_parameters();
  if (gpar->limit_params.select_limit != 0  &&
       // limit can not be an expression but can be parameter
      (!gpar->limit_params.select_limit->basic_const_item() ||
       ((ha_rows)gpar->limit_params.select_limit->val_int()) < lim))
    return false;

  Query_arena *arena, backup;
  arena= thd->activate_stmt_arena_if_needed(&backup);

  gpar->limit_params.select_limit=
    new (thd->mem_root) Item_int(thd, lim, MAX_BIGINT_WIDTH);
  if (gpar->limit_params.select_limit == 0)
    return true; // EOM

  unit->set_limit(gpar);

  gpar->limit_params.explicit_limit= true; // to show in EXPLAIN

  if (arena)
    thd->restore_active_arena(arena, &backup);

  return false;
}


/**