diff options
Diffstat (limited to 'sql/opt_split.cc')
| -rw-r--r-- | sql/opt_split.cc | 72 |
1 files changed, 60 insertions, 12 deletions
diff --git a/sql/opt_split.cc b/sql/opt_split.cc index 3a873e220b6..bb3aec9ee8d 100644 --- a/sql/opt_split.cc +++ b/sql/opt_split.cc @@ -228,6 +228,7 @@ #include "mariadb.h" #include "sql_select.h" +#include "opt_trace.h" /* Info on a splitting field */ struct SplM_field_info @@ -387,6 +388,9 @@ bool JOIN::check_for_splittable_materialized() if (!partition_list) return false; + Json_writer_object trace_wrapper(thd); + Json_writer_object trace_split(thd, "check_split_materialized"); + ORDER *ord; Dynamic_array<SplM_field_ext_info> candidates; @@ -432,7 +436,10 @@ bool JOIN::check_for_splittable_materialized() } } if (candidates.elements() == 0) // no candidates satisfying (8.1) && (8.2) + { + trace_split.add("not_applicable", "group list has no candidates"); return false; + } /* For each table from this join find the keys that can be used for ref access @@ -491,7 +498,11 @@ bool JOIN::check_for_splittable_materialized() } if (!spl_field_cnt) // No candidate field can be accessed by ref => !(9) + { + trace_split.add("not_applicable", + "no candidate field can be accessed through ref"); return false; + } /* Create a structure of the type SplM_opt_info and fill it with @@ -509,16 +520,22 @@ bool JOIN::check_for_splittable_materialized() spl_opt_info->tables_usable_for_splitting= 0; spl_opt_info->spl_field_cnt= spl_field_cnt; spl_opt_info->spl_fields= spl_field; - for (cand= cand_start; cand < cand_end; cand++) + { - if (!cand->is_usable_for_ref_access) - continue; - spl_field->producing_item= cand->producing_item; - spl_field->underlying_field= cand->underlying_field; - spl_field->mat_field= cand->mat_field; - spl_opt_info->tables_usable_for_splitting|= - cand->underlying_field->table->map; - spl_field++; + Json_writer_array trace_range(thd, "split_candidates"); + for (cand= cand_start; cand < cand_end; cand++) + { + if (!cand->is_usable_for_ref_access) + continue; + trace_range.add(cand->producing_item); + + spl_field->producing_item= cand->producing_item; + spl_field->underlying_field= cand->underlying_field; + spl_field->mat_field= cand->mat_field; + spl_opt_info->tables_usable_for_splitting|= + cand->underlying_field->table->map; + spl_field++; + } } /* Attach this info to the table T */ @@ -773,7 +790,7 @@ void JOIN::add_keyuses_for_splitting() bzero((char*) &keyuse_ext_end, sizeof(keyuse_ext_end)); if (ext_keyuses_for_splitting->push(keyuse_ext_end)) goto err; - + // psergey-todo: trace anything here? spl_opt_info->unsplit_card= join_record_count; rec_len= table->s->rec_buff_length; @@ -946,7 +963,8 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, uint best_key= 0; uint best_key_parts= 0; table_map best_param_tables; - + Json_writer_object trace_obj(thd, "choose_best_splitting"); + Json_writer_array trace_arr(thd, "considered_keys"); /* Check whether there are keys that can be used to join T employing splitting and if so, select the best out of such keys @@ -999,6 +1017,13 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, best_rec_per_key= rec_per_key; best_key_keyuse_ext_start= key_keyuse_ext_start; best_param_tables= needed_in_prefix; + // trace table, key_name, parts, needed_tables. + Json_writer_object cur_index(thd); + cur_index. + add("table_name", best_table->alias.ptr()). + add("index", best_table->key_info[best_key].name). + add("rec_per_key", best_rec_per_key). + add("param_tables", best_param_tables); } keyuse_ext++; } @@ -1006,6 +1031,8 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, } while (keyuse_ext->table == table); } + trace_arr.end(); + spl_opt_info->last_plan= 0; double refills= DBL_MAX; table_map excluded_tables= remaining_tables | this->join->sjm_lookup_tables; @@ -1031,6 +1058,10 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, break; } } + + trace_obj.add("refills", refills). + add("spl_pd_boundary", *spl_pd_boundary); + /* The key for splitting was chosen, look for the plan for this key in the cache @@ -1042,11 +1073,13 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, The plan for the chosen key has not been found in the cache. Build a new plan and save info on it in the cache */ + Json_writer_array wrapper(thd, "split_plan_search"); table_map all_table_map= (((table_map) 1) << join->table_count) - 1; reset_validity_vars_for_keyuses(best_key_keyuse_ext_start, best_table, best_key, excluded_tables, true); choose_plan(join, all_table_map & ~join->const_table_map); + wrapper.end(); /* Check that the chosen plan is really a splitting plan. If not or if there is not enough memory to save the plan in the cache @@ -1064,6 +1097,7 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, { reset_validity_vars_for_keyuses(best_key_keyuse_ext_start, best_table, best_key, excluded_tables, false); + trace_obj.add("split_plan_discarded", "constructed unapplicable query plan"); return 0; } @@ -1089,9 +1123,20 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, reset_validity_vars_for_keyuses(best_key_keyuse_ext_start, best_table, best_key, excluded_tables, false); } + else + trace_obj.add("cached_plan_found", 1); if (spl_plan) { + trace_obj. + add("lead_table", spl_plan->table->alias.ptr()). + add("index", spl_plan->table->key_info[spl_plan->key].name). + add("parts", spl_plan->parts). + add("split_sel", spl_plan->split_sel). + add("cost", spl_plan->cost). + add("records", (ha_rows) (records * spl_plan->split_sel)). + add("refills", refills); + if (refills * spl_plan->cost < spl_opt_info->unsplit_cost) { /* @@ -1100,7 +1145,10 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, */ spl_opt_info->last_plan= spl_plan; spl_opt_info->last_refills= refills; + trace_obj.add("chosen", true); } + else + trace_obj.add("chosen", false); } } @@ -1132,7 +1180,7 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(uint idx, @details This function injects equalities pushed into a derived table T for which the split optimization has been chosen by the optimizer. The function - is called by JOIN::inject_splitting_cond_for_all_tables_with_split_op(). + is called by JOIN::inject_splitting_cond_for_all_tables_with_split_opt(). All equalities usable for splitting T whose right parts do not depend on any of the 'excluded_tables' can be pushed into the where clause of the derived table T. |