mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 20:12:31 +01:00
7b988e5ceb
Added:
1) estimated_join_cardinality
2) best_chosen_access_method for a table
3) best_join_order
266 lines
8.7 KiB
Text
266 lines
8.7 KiB
Text
set @innodb_stats_persistent_save= @@innodb_stats_persistent;
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set @innodb_stats_persistent_sample_pages_save=
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@@innodb_stats_persistent_sample_pages;
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set global innodb_stats_persistent= 1;
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set global innodb_stats_persistent_sample_pages=100;
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create table t1
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(
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pk1 int not null,
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pk2 int not null,
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key1 int not null,
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key2 int not null,
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key (key1),
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key (key2),
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primary key (pk1, pk2)
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)engine=Innodb;
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analyze table t1;
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Table Op Msg_type Msg_text
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test.t1 analyze status Engine-independent statistics collected
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test.t1 analyze status OK
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set optimizer_trace="enabled=on";
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set @tmp_index_merge_ror_cpk=@@optimizer_switch;
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set optimizer_switch='extended_keys=off';
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explain select * from t1 where pk1 != 0 and key1 = 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref PRIMARY,key1 key1 4 const 1 Using index condition
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select * from information_schema.OPTIMIZER_TRACE;
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QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
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explain select * from t1 where pk1 != 0 and key1 = 1 {
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"steps": [
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{
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"join_preparation": {
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"select_id": 1,
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"steps": [
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{
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"expanded_query": "select t1.pk1 AS pk1,t1.pk2 AS pk2,t1.key1 AS key1,t1.key2 AS key2 from t1 where t1.pk1 <> 0 and t1.key1 = 1"
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}
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]
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}
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},
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{
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"join_optimization": {
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"select_id": 1,
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"steps": [
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{
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"condition_processing": {
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"condition": "WHERE",
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"original_condition": "t1.pk1 <> 0 and t1.key1 = 1",
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"steps": [
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{
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"transformation": "equality_propagation",
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"resulting_condition": "t1.pk1 <> 0 and multiple equal(1, t1.key1)"
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},
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{
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"transformation": "constant_propagation",
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"resulting_condition": "t1.pk1 <> 0 and multiple equal(1, t1.key1)"
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},
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{
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"transformation": "trivial_condition_removal",
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"resulting_condition": "t1.pk1 <> 0 and multiple equal(1, t1.key1)"
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}
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]
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}
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},
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{
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"table_dependencies": [
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{
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"table": "t1",
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"row_may_be_null": false,
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"map_bit": 0,
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"depends_on_map_bits": []
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}
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]
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},
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{
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"ref_optimizer_key_uses": [
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{
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"table": "t1",
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"field": "key1",
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"equals": "1",
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"null_rejecting": false
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}
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]
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},
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{
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"rows_estimation": [
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{
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"table": "t1",
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"range_analysis": {
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"table_scan": {
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"rows": 1000,
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"cost": 206.1
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},
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"potential_range_indexes": [
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{
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"index": "PRIMARY",
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"usable": true,
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"key_parts": ["pk1", "pk2"]
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},
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{
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"index": "key1",
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"usable": true,
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"key_parts": ["key1"]
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},
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{
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"index": "key2",
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"usable": false,
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"cause": "not applicable"
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}
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],
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"setup_range_conditions": [],
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"group_index_range": {
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"chosen": false,
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"cause": "no group by or distinct"
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},
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"analyzing_range_alternatives": {
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"range_scan_alternatives": [
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{
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"index": "PRIMARY",
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"ranges": ["(pk1) < (0)", "(0) < (pk1)"],
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"rowid_ordered": true,
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"using_mrr": false,
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"index_only": false,
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"rows": 1000,
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"cost": 206.39,
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"chosen": false,
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"cause": "cost"
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},
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{
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"index": "key1",
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"ranges": ["(1) <= (key1) <= (1)"],
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"rowid_ordered": true,
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"using_mrr": false,
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"index_only": false,
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"rows": 1,
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"cost": 2.3751,
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"chosen": true
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}
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],
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"analyzing_roworder_intersect": {
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"intersecting_indexes": [
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{
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"index": "key1",
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"index_scan_cost": 1.0001,
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"cumulated_index_scan_cost": 1.0001,
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"disk_sweep_cost": 1.0014,
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"cumulative_total_cost": 2.0015,
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"usable": true,
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"matching_rows_now": 1,
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"intersect_covering_with_this_index": false,
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"chosen": true
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}
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],
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"clustered_pk": {
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"clustered_pk_added_to_intersect": false,
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"cause": "cost"
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},
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"chosen": false,
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"cause": "too few indexes to merge"
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},
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"analyzing_index_merge_union": []
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},
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"chosen_range_access_summary": {
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"range_access_plan": {
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"type": "range_scan",
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"index": "key1",
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"rows": 1,
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"ranges": ["(1) <= (key1) <= (1)"]
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},
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"rows_for_plan": 1,
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"cost_for_plan": 2.3751,
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"chosen": true
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}
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}
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},
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{
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"selectivity_for_indexes": [
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{
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"index_name": "PRIMARY",
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"selectivity_from_index": 1
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},
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{
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"index_name": "key1",
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"selectivity_from_index": 0.001
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}
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],
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"selectivity_for_columns": [],
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"cond_selectivity": 0.001
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}
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]
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},
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{
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"considered_execution_plans": [
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{
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"plan_prefix": [],
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"table": "t1",
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"best_access_path": {
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"considered_access_paths": [
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{
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"access_type": "ref",
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"index": "key1",
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"used_range_estimates": true,
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"rows": 1,
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"cost": 2,
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"chosen": true
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},
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{
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"type": "scan",
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"chosen": false,
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"cause": "cost"
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}
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],
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"chosen_access_method": {
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"type": "ref",
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"records": 1,
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"cost": 2,
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"uses_join_buffering": false,
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"filter_used": false
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}
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},
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"rows_for_plan": 1,
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"cost_for_plan": 2.2,
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"estimated_join_cardinality": 1
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}
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]
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},
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{
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"best_join_order": ["t1"]
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},
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{
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"attaching_conditions_to_tables": {
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"original_condition": "t1.key1 = 1 and t1.pk1 <> 0",
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"attached_conditions_computation": [],
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"attached_conditions_summary": [
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{
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"table": "t1",
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"attached": "t1.pk1 <> 0"
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}
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]
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}
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}
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]
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}
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},
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{
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"join_execution": {
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"select_id": 1,
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"steps": []
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}
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}
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]
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} 0 0
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drop table t1;
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set @@optimizer_switch= @tmp_index_merge_ror_cpk;
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set global innodb_stats_persistent= @innodb_stats_persistent_save;
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set global innodb_stats_persistent_sample_pages=
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@innodb_stats_persistent_sample_pages_save;
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#
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# MDEV-18962: ASAN heap-buffer-overflow in Single_line_formatting_helper::on_add_str with optimizer trace
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#
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CREATE TABLE t1 (a date not null, b time, key(a), key(b)) ENGINE=InnoDB;
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INSERT INTO t1 VALUES ('1991-09-09','00:00:00'),('2032-08-24','02:22:24');
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SET SESSION optimizer_trace = 'enabled=on';
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SELECT * FROM t1 WHERE b IS NULL AND a = '2000-01-01';
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a b
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DROP TABLE t1;
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set optimizer_trace="enabled=off";
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