diff options
Diffstat (limited to 'sql/opt_range.cc')
| -rw-r--r-- | sql/opt_range.cc | 48 |
1 files changed, 25 insertions, 23 deletions
diff --git a/sql/opt_range.cc b/sql/opt_range.cc index a3c5dbcb199..bf968878a72 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -356,9 +356,8 @@ QUICK_RANGE_SELECT *get_quick_select(PARAM *param,uint index, uint mrr_buf_size, MEM_ROOT *alloc); static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree, bool index_read_must_be_used, - bool update_tbl_stats, - double read_time, - bool ror_scans_required); + bool for_range_access, + double read_time); static TRP_INDEX_INTERSECT *get_best_index_intersect(PARAM *param, SEL_TREE *tree, double read_time); @@ -2907,7 +2906,6 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use, It is possible to use a range-based quick select (but it might be slower than 'all' table scan). */ - TRP_RANGE *range_trp; TRP_ROR_INTERSECT *rori_trp; TRP_INDEX_INTERSECT *intersect_trp; bool can_build_covering= FALSE; @@ -2916,9 +2914,9 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use, remove_nonrange_trees(¶m, tree); /* Get best 'range' plan and prepare data for making other plans */ - if ((range_trp= get_key_scans_params(¶m, tree, - only_single_index_range_scan, TRUE, - best_read_time, FALSE))) + if (auto range_trp= get_key_scans_params(¶m, tree, + only_single_index_range_scan, + true, best_read_time)) { best_trp= range_trp; best_read_time= best_trp->read_cost; @@ -5083,9 +5081,6 @@ TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge, n_child_scans))) DBUG_RETURN(NULL); - const bool only_ror_scans_required= !optimizer_flag(param->thd, - OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION); - Json_writer_object trace_best_disjunct(thd); Json_writer_array to_merge(thd, "indexes_to_merge"); /* @@ -5101,8 +5096,7 @@ TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge, "tree in SEL_IMERGE");); Json_writer_object trace_idx(thd); if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE, - read_time, - only_ror_scans_required))) + read_time))) { /* One of index scans in this index_merge is more expensive than entire @@ -5462,9 +5456,12 @@ TABLE_READ_PLAN *merge_same_index_scans(PARAM *param, SEL_IMERGE *imerge, a random order 2. the functions that estimate the cost of a range scan and an index merge retrievals are not well calibrated + + As the best range access has been already chosen it does not + make sense to evaluate the one obtained from a degenerated + index merge. */ - trp= get_key_scans_params(param, *imerge->trees, FALSE, TRUE, - read_time, FALSE); + trp= 0; } DBUG_RETURN(trp); @@ -7347,9 +7344,9 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param, tree make range select for this SEL_TREE index_read_must_be_used if TRUE, assume 'index only' option will be set (except for clustered PK indexes) + for_range_access if TRUE the function is called to get the best range + plan for range access, not for index merge access read_time don't create read plans with cost > read_time. - only_ror_scans_required set to TRUE when we are only interested - in ROR scan RETURN Best range read plan NULL if no plan found or error occurred @@ -7357,9 +7354,8 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param, static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree, bool index_read_must_be_used, - bool update_tbl_stats, - double read_time, - bool only_ror_scans_required) + bool for_range_access, + double read_time) { uint idx, UNINIT_VAR(best_idx); SEL_ARG *key_to_read= NULL; @@ -7387,7 +7383,8 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree, (INDEX_SCAN_INFO **) alloc_root(param->mem_root, sizeof(INDEX_SCAN_INFO *) * param->keys); } - tree->index_scans_end= tree->index_scans; + tree->index_scans_end= tree->index_scans; + for (idx= 0; idx < param->keys; idx++) { SEL_ARG *key= tree->keys[idx]; @@ -7411,10 +7408,15 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree, trace_idx.add("index", param->table->key_info[keynr].name); found_records= check_quick_select(param, idx, read_index_only, key, - update_tbl_stats, &mrr_flags, + for_range_access, &mrr_flags, &buf_size, &cost, &is_ror_scan); - if (only_ror_scans_required && !is_ror_scan) + + if (!for_range_access && !is_ror_scan && + !optimizer_flag(param->thd,OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION)) + { + /* The scan is not a ROR-scan, just skip it */ continue; + } if (found_records != HA_POS_ERROR && tree->index_scans && (index_scan= (INDEX_SCAN_INFO *)alloc_root(param->mem_root, @@ -7443,7 +7445,7 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree, .add("index_only", read_index_only) .add("rows", found_records) .add("cost", cost.total_cost()); - } + } if ((found_records != HA_POS_ERROR) && is_ror_scan) { tree->n_ror_scans++; |