diff options
| -rw-r--r-- | sql/sql_select.cc | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index a865c75184f..70c0a80ba2a 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -9780,6 +9780,23 @@ bool JOIN::get_best_combination() if (aggr_tables > 2) aggr_tables= 2; + +#ifndef DBUG_OFF + dbug_join_tab_array_size= top_join_tab_count + aggr_tables; +#endif + /* + NOTE: The above computation of aggr_tables can produce wrong result because some + of the variables it uses may change their values after we leave this function. + Known examples: + - Dangerous: using_outer_summary_function=false at this point. Added + DBUG_ASSERT below to demonstrate. Can this cause us to allocate less + space than we would need? + - Not dangerous: select_distinct can be true here but be assigned false + afterwards. + */ + aggr_tables= 2; + DBUG_ASSERT(!tmp_table_param.using_outer_summary_function); + if (!(join_tab= (JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)* (top_join_tab_count + aggr_tables)))) DBUG_RETURN(TRUE); @@ -9789,10 +9806,6 @@ bool JOIN::get_best_combination() fix_semijoin_strategies_for_picked_join_order(this); -#ifndef DBUG_OFF - dbug_join_tab_array_size= top_join_tab_count + aggr_tables; -#endif - if (inject_splitting_cond_for_all_tables_with_split_opt()) DBUG_RETURN(TRUE); |