diff options
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/opt_subselect.cc | 23 | ||||
| -rw-r--r-- | sql/sql_select.cc | 30 | ||||
| -rw-r--r-- | sql/sql_select.h | 5 |
3 files changed, 49 insertions, 9 deletions
diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc index 8cc11253f47..1bbdbf14ea4 100644 --- a/sql/opt_subselect.cc +++ b/sql/opt_subselect.cc @@ -353,7 +353,7 @@ int check_and_do_in_subquery_rewrites(JOIN *join) } else { - DBUG_PRINT("info", ("Subquery can't be converted to semi-join")); + DBUG_PRINT("info", ("Subquery can't be converted to merged semi-join")); /* Test if the user has set a legal combination of optimizer switches. */ if (!optimizer_flag(thd, OPTIMIZER_SWITCH_IN_TO_EXISTS) && !optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION)) @@ -395,7 +395,8 @@ int check_and_do_in_subquery_rewrites(JOIN *join) join->sj_subselects list to be populated for every EXECUTE. */ - if (!select_lex->is_part_of_union() && // 1 + if (optimizer_flag(thd, OPTIMIZER_SWITCH_MATERIALIZATION) && + !select_lex->is_part_of_union() && // 1 parent_unit->first_select()->leaf_tables && // 2 thd->lex->sql_command == SQLCOM_SELECT && // * select_lex->outer_select()->leaf_tables && // 2A @@ -888,8 +889,6 @@ void get_delayed_table_estimates(TABLE *table, double *startup_cost) { Item_in_subselect *item= table->pos_in_table_list->jtbm_subselect; - double rows; - double read_time; //psergey-merge: moving off here: item->optimize(&rows, &read_time); @@ -899,10 +898,11 @@ void get_delayed_table_estimates(TABLE *table, subselect_hash_sj_engine *hash_sj_engine= ((subselect_hash_sj_engine*)item->engine); - *out_rows= (ha_rows)rows; - *startup_cost= read_time; + *out_rows= (ha_rows)item->jtbm_record_count; + *startup_cost= item->jtbm_read_time; + /* Calculate cost of scanning the temptable */ - double data_size= rows * hash_sj_engine->tmp_table->s->reclength; + double data_size= (*out_rows) * hash_sj_engine->tmp_table->s->reclength; /* Do like in handler::read_time */ *scan_time= data_size/IO_SIZE + 2; } @@ -1326,6 +1326,9 @@ static bool convert_subq_to_jtbm(JOIN *parent_join, // DBUG_RETURN(TRUE); double rows; double read_time; + + // psergey-merge: disable IN->EXISTS for JTBM subqueries, for now. + subq_pred->in_strategy &= ~SUBS_IN_TO_EXISTS; subq_pred->optimize(&rows, &read_time); subq_pred->jtbm_read_time= read_time; @@ -1710,10 +1713,16 @@ bool optimize_semijoin_nests(JOIN *join, table_map all_table_map) sjm->tables= n_tables; sjm->is_used= FALSE; double subjoin_out_rows, subjoin_read_time; + + /* join->get_partial_cost_and_fanout(n_tables + join->const_tables, table_map(-1), &subjoin_read_time, &subjoin_out_rows); + */ + join->get_prefix_cost_and_fanout(n_tables, + &subjoin_read_time, + &subjoin_out_rows); sjm->materialization_cost.convert_from_cost(subjoin_read_time); sjm->rows= subjoin_out_rows; diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 261bdf0e91f..a07900d328b 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -5935,6 +5935,36 @@ void JOIN::get_partial_cost_and_fanout(uint end_tab_idx, } +/* + Get prefix cost and fanout. This function is different from + get_partial_cost_and_fanout: + - it operates on a JOIN that haven't yet finished its optimization phase (in + particular, fix_semijoin_strategies_for_picked_join_order() and + get_best_combination() haven't been called) + - it assumes the the join prefix doesn't have any semi-join plans + + These assumptions are met by the caller of the function. +*/ + +void JOIN::get_prefix_cost_and_fanout(uint n_tables, + double *read_time_arg, + double *record_count_arg) +{ + double record_count= 1; + double read_time= 0.0; + for (uint i= const_tables; i < n_tables + const_tables ; i++) + { + if (best_positions[i].records_read) + { + record_count *= best_positions[i].records_read; + read_time += best_positions[i].read_time; + } + } + *read_time_arg= read_time;// + record_count / TIME_FOR_COMPARE; + *record_count_arg= record_count; +} + + /** Find a good, possibly optimal, query execution plan (QEP) by a possibly exhaustive search. diff --git a/sql/sql_select.h b/sql/sql_select.h index 1ce2190497d..c19692a19a9 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -1138,12 +1138,13 @@ public: max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT; } bool choose_subquery_plan(table_map join_tables); - //void get_partial_join_cost(uint n_tables, - // double *read_time_arg, double *record_count_arg); void get_partial_cost_and_fanout(uint end_tab_idx, table_map filter_map, double *read_time_arg, double *record_count_arg); + void get_prefix_cost_and_fanout(uint n_tables, + double *read_time_arg, + double *record_count_arg); private: /** TRUE if the query contains an aggregate function but has no GROUP |