mirror of
https://github.com/MariaDB/server.git
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d1e5fa8917
my_like_range*() can create longer keys than Field::char_length(). This caused warnings during print_range(). Fix: Suppressing warnings in print_range().
9312 lines
310 KiB
Text
9312 lines
310 KiB
Text
SELECT table_name, column_name FROM information_schema.columns where table_name="OPTIMIZER_TRACE";
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table_name column_name
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OPTIMIZER_TRACE QUERY
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OPTIMIZER_TRACE TRACE
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OPTIMIZER_TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE
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OPTIMIZER_TRACE INSUFFICIENT_PRIVILEGES
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set optimizer_trace="enabled=on";
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show variables like 'optimizer_trace';
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Variable_name Value
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optimizer_trace enabled=on
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set optimizer_trace="enabled=off";
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show variables like 'optimizer_trace';
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Variable_name Value
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optimizer_trace enabled=off
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create table t1 (a int, b int);
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insert into t1 values (1,2),(2,3);
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create table t2 (b int);
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insert into t2 values (1),(2);
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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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analyze table t2;
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Table Op Msg_type Msg_text
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test.t2 analyze status Engine-independent statistics collected
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test.t2 analyze status OK
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create function f1 (a int) returns INT
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return 1;
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create view v1 as select * from t1 where t1.a=1;
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create view v2 as select * from t1 where t1.a=1 group by t1.b;
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set optimizer_trace="enabled=on";
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# Mergeable views/derived tables
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select * from v1;
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a b
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1 2
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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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select * from v1 {
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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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"view": {
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"table": "v1",
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"select_id": 2,
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"algorithm": "merged"
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}
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},
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{
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"join_preparation": {
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"select_id": 2,
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"steps": [
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{
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"expanded_query": "/* select#2 */ select t1.a AS a,t1.b AS b from t1 where t1.a = 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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"expanded_query": "/* select#1 */ select t1.a AS a,t1.b AS b from v1"
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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.a = 1",
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"steps": [
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{
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"transformation": "equality_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "constant_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "trivial_condition_removal",
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"resulting_condition": "multiple equal(1, t1.a)"
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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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{
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"rows_estimation": [
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{
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"selectivity_for_indexes": [],
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"selectivity_for_columns": [
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{
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"column_name": "a",
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"ranges": ["1 <= a <= 1"],
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"selectivity_from_histogram": 0.5
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}
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],
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"cond_selectivity": 0.5
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},
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{
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"table": "t1",
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"table_scan": {
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"rows": 2,
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"cost": 2.004394531
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}
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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": "scan",
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"resulting_rows": 1,
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"cost": 2.204394531,
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"chosen": true
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}
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],
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"chosen_access_method": {
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"type": "scan",
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"records": 1,
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"cost": 2.204394531,
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"uses_join_buffering": false
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}
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},
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"rows_for_plan": 1,
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"cost_for_plan": 2.404394531,
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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.a = 1",
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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.a = 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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}
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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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select * from (select * from t1 where t1.a=1)q;
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a b
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1 2
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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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select * from (select * from t1 where t1.a=1)q {
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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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"derived": {
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"table": "q",
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"select_id": 2,
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"algorithm": "merged"
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}
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},
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{
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"join_preparation": {
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"select_id": 2,
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"steps": [
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{
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"expanded_query": "/* select#2 */ select t1.a AS a,t1.b AS b from t1 where t1.a = 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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"expanded_query": "/* select#1 */ select t1.a AS a,t1.b AS b from (/* select#2 */ select t1.a AS a,t1.b AS b from t1 where t1.a = 1) q"
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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.a = 1",
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"steps": [
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{
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"transformation": "equality_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "constant_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "trivial_condition_removal",
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"resulting_condition": "multiple equal(1, t1.a)"
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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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{
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"rows_estimation": [
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{
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"selectivity_for_indexes": [],
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"selectivity_for_columns": [
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{
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"column_name": "a",
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"ranges": ["1 <= a <= 1"],
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"selectivity_from_histogram": 0.5
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}
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],
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"cond_selectivity": 0.5
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},
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{
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"table": "t1",
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"table_scan": {
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"rows": 2,
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"cost": 2.004394531
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}
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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": "scan",
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"resulting_rows": 1,
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"cost": 2.204394531,
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"chosen": true
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}
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],
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"chosen_access_method": {
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"type": "scan",
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"records": 1,
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"cost": 2.204394531,
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"uses_join_buffering": false
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}
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},
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"rows_for_plan": 1,
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"cost_for_plan": 2.404394531,
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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.a = 1",
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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.a = 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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}
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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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# Non-Mergeable views
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select * from v2;
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a b
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1 2
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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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select * from v2 {
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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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"view": {
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"table": "v2",
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"select_id": 2,
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"algorithm": "materialized"
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}
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},
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{
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"join_preparation": {
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"select_id": 2,
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"steps": [
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{
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"expanded_query": "/* select#2 */ select t1.a AS a,t1.b AS b from t1 where t1.a = 1 group by t1.b"
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}
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]
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}
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},
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{
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"expanded_query": "/* select#1 */ select v2.a AS a,v2.b AS b from v2"
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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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"join_optimization": {
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"select_id": 2,
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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.a = 1",
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"steps": [
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{
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"transformation": "equality_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "constant_propagation",
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"resulting_condition": "multiple equal(1, t1.a)"
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},
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{
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"transformation": "trivial_condition_removal",
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"resulting_condition": "multiple equal(1, t1.a)"
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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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{
|
|
"rows_estimation": [
|
|
{
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"selectivity_for_indexes": [],
|
|
"selectivity_for_columns": [
|
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{
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"column_name": "a",
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"ranges": ["1 <= a <= 1"],
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"selectivity_from_histogram": 0.5
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}
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],
|
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"cond_selectivity": 0.5
|
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},
|
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{
|
|
"table": "t1",
|
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"table_scan": {
|
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"rows": 2,
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"cost": 2.004394531
|
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}
|
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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": {
|
|
"considered_access_paths": [
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{
|
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"access_type": "scan",
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"resulting_rows": 1,
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"cost": 2.204394531,
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"chosen": true,
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"use_tmp_table": true
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}
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],
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"chosen_access_method": {
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"type": "scan",
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"records": 1,
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"cost": 2.204394531,
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"uses_join_buffering": false
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}
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},
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"rows_for_plan": 1,
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"cost_for_plan": 2.404394531,
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"cost_for_sorting": 1,
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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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"check_split_materialized": {
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"not_applicable": "no candidate field can be accessed through ref"
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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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{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.a = 1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
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"attached": "t1.a = 1"
|
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}
|
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]
|
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}
|
|
},
|
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{
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"test_if_skip_sort_order": []
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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": "<derived2>",
|
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"row_may_be_null": false,
|
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"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "<derived2>",
|
|
"table_scan": {
|
|
"rows": 2,
|
|
"cost": 2
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "<derived2>",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 2,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 2,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 2,
|
|
"cost_for_plan": 2.4,
|
|
"estimated_join_cardinality": 2
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["<derived2>"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "<derived2>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_execution": {
|
|
"select_id": 2,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1,t2;
|
|
drop view v1,v2;
|
|
drop function f1;
|
|
create table t1(a int, b int);
|
|
insert into t1 values (0,0),(1,1),(2,1),(3,2),(4,3),
|
|
(5,3),(6,3),(7,3),(8,3),(9,3);
|
|
create table t2(a int, b int);
|
|
insert into t2 values (0,0),(1,1),(2,1),(3,2),(4,3),
|
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(5,3),(6,3),(7,3),(8,3),(9,3);
|
|
ANALYZE TABLE t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
ANALYZE TABLE t2;
|
|
Table Op Msg_type Msg_text
|
|
test.t2 analyze status Engine-independent statistics collected
|
|
test.t2 analyze status OK
|
|
create view v1 as select a from t1 group by b;
|
|
create view v2 as select a from t2;
|
|
# Mergeable view
|
|
explain select * from v2 ;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t2 ALL NULL NULL NULL NULL 10
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from v2 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"view": {
|
|
"table": "v2",
|
|
"select_id": 2,
|
|
"algorithm": "merged"
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#2 */ select t2.a AS a from t2"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select t2.a AS a from v2"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t2",
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 2.021972656
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.021972656,
|
|
"estimated_join_cardinality": 10
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t2"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t2",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
# Non-Mergeable view
|
|
explain select * from v1 ;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 10
|
|
2 DERIVED t1 ALL NULL NULL NULL NULL 10 Using temporary; Using filesort
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from v1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"view": {
|
|
"table": "v1",
|
|
"select_id": 2,
|
|
"algorithm": "materialized"
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#2 */ select t1.a AS a from t1 group by t1.b"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select v1.a AS a from v1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 2.021972656
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true,
|
|
"use_tmp_table": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.021972656,
|
|
"cost_for_sorting": 10,
|
|
"estimated_join_cardinality": 10
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"check_split_materialized": {
|
|
"not_applicable": "group list has no candidates"
|
|
}
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": []
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "<derived2>",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "<derived2>",
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 10
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "<derived2>",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 10,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 10,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 12,
|
|
"estimated_join_cardinality": 10
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["<derived2>"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "<derived2>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_execution": {
|
|
"select_id": 2,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1,t2;
|
|
drop view v1,v2;
|
|
#
|
|
# print ref-keyues array
|
|
#
|
|
create table t0 (a int);
|
|
INSERT INTO t0 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (a int, b int, c int, key(a));
|
|
insert into t1 select A.a*10 + B.a, A.a*10 + B.a, A.a*10 + B.a from t0 A, t0 B;
|
|
create table t2(a int, b int, c int , key(a));
|
|
insert into t2 select A.a*10 + B.a, A.a*10 + B.a, A.a*10 + B.a from t0 A, t0 B;
|
|
analyze table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status Table is already up to date
|
|
analyze table t2;
|
|
Table Op Msg_type Msg_text
|
|
test.t2 analyze status Engine-independent statistics collected
|
|
test.t2 analyze status Table is already up to date
|
|
explain select * from t1,t2 where t1.a=t2.b+2 and t2.a= t1.b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL a NULL NULL NULL 100 Using where
|
|
1 SIMPLE t2 ref a a 5 test.t1.b 1 Using where
|
|
select * from information_schema.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1,t2 where t1.a=t2.b+2 and t2.a= t1.b {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.a AS a,t1.b AS b,t1.c AS c,t2.a AS a,t2.b AS b,t2.c AS c from t1 join t2 where t1.a = t2.b + 2 and t2.a = t1.b"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.a = t2.b + 2 and t2.a = t1.b",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "t1.a = t2.b + 2 and multiple equal(t2.a, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "t1.a = t2.b + 2 and multiple equal(t2.a, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "t1.a = t2.b + 2 and multiple equal(t2.a, t1.b)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "t2.b + 2",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"field": "a",
|
|
"equals": "t1.b",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 100,
|
|
"cost": 2.317382812
|
|
}
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"table_scan": {
|
|
"rows": 100,
|
|
"cost": 2.317382812
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.317382812,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 100,
|
|
"cost": 2.317382812,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 100,
|
|
"cost_for_plan": 22.31738281,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not available",
|
|
"rows": 1,
|
|
"cost": 200.0585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.317382812,
|
|
"chosen": false
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 200.0585794,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 100,
|
|
"cost_for_plan": 242.3759623,
|
|
"estimated_join_cardinality": 100
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.317382812,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 100,
|
|
"cost": 2.317382812,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 100,
|
|
"cost_for_plan": 22.31738281,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t2"],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not available",
|
|
"rows": 1,
|
|
"cost": 200.0585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.317382812,
|
|
"chosen": false
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 200.0585794,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 100,
|
|
"cost_for_plan": 242.3759623,
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1", "t2"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t2.a = t1.b and t1.a = t2.b + 2",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": "t1.b is not null"
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"attached": "t1.a = t2.b + 2"
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1,t2,t0;
|
|
#
|
|
# group_by min max optimization
|
|
#
|
|
CREATE TABLE t1 (id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, a INT NOT NULL, KEY(a));
|
|
analyze table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
EXPLAIN SELECT DISTINCT a FROM t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL a 4 NULL 5 Using index for group-by
|
|
select * from information_schema.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
EXPLAIN SELECT DISTINCT a FROM t1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select distinct t1.a AS a from t1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 65536,
|
|
"cost": 13255.2
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "PRIMARY",
|
|
"usable": false,
|
|
"cause": "not applicable"
|
|
},
|
|
{
|
|
"index": "a",
|
|
"usable": true,
|
|
"key_parts": ["a"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "a",
|
|
"cost": 13377.39141,
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
},
|
|
"group_index_range": {
|
|
"distinct_query": true,
|
|
"potential_group_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"covering": true,
|
|
"rows": 5,
|
|
"cost": 6.25
|
|
}
|
|
]
|
|
},
|
|
"best_group_range_summary": {
|
|
"type": "index_group",
|
|
"index": "a",
|
|
"min_max_arg": null,
|
|
"min_aggregate": false,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 5,
|
|
"cost": 6.25,
|
|
"key_parts_used_for_access": ["a"],
|
|
"ranges": [],
|
|
"chosen": true
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "index_group",
|
|
"index": "a",
|
|
"min_max_arg": null,
|
|
"min_aggregate": false,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 5,
|
|
"cost": 6.25,
|
|
"key_parts_used_for_access": ["a"],
|
|
"ranges": []
|
|
},
|
|
"rows_for_plan": 5,
|
|
"cost_for_plan": 6.25,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "index_merge",
|
|
"resulting_rows": 5,
|
|
"cost": 6.25,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "index_merge",
|
|
"records": 5,
|
|
"cost": 6.25,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 5,
|
|
"cost_for_plan": 7.25,
|
|
"estimated_join_cardinality": 5
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": []
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1;
|
|
#
|
|
# With group by , where clause and MIN/MAX function
|
|
#
|
|
CREATE TABLE t1 (a INT, b INT, c int, d int, KEY(a,b,c,d));
|
|
INSERT INTO t1 VALUES (1,1,1,1), (2,2,2,2), (3,3,3,3), (4,4,4,4), (1,0,1,1), (3,2,3,3), (4,5,4,4);
|
|
ANALYZE TABLE t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
EXPLAIN SELECT MIN(d) FROM t1 where b=2 and c=3 group by a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL a 20 NULL 8 Using where; Using index for group-by
|
|
select * from information_schema.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
EXPLAIN SELECT MIN(d) FROM t1 where b=2 and c=3 group by a {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select min(t1.d) AS `MIN(d)` from t1 where t1.b = 2 and t1.c = 3 group by t1.a"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.b = 2 and t1.c = 3",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "multiple equal(2, t1.b) and multiple equal(3, t1.c)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "multiple equal(2, t1.b) and multiple equal(3, t1.c)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(2, t1.b) and multiple equal(3, t1.c)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 7,
|
|
"cost": 5.429052734
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"usable": true,
|
|
"key_parts": ["a", "b", "c", "d"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "a",
|
|
"cost": 2.409226263,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"potential_group_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"covering": true,
|
|
"ranges": ["(2,3) <= (b,c) <= (2,3)"],
|
|
"rows": 8,
|
|
"cost": 2.2
|
|
}
|
|
]
|
|
},
|
|
"best_group_range_summary": {
|
|
"type": "index_group",
|
|
"index": "a",
|
|
"min_max_arg": "d",
|
|
"min_aggregate": true,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 8,
|
|
"cost": 2.2,
|
|
"key_parts_used_for_access": ["a", "b", "c"],
|
|
"ranges": ["(2,3) <= (b,c) <= (2,3)"],
|
|
"chosen": true
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "index_group",
|
|
"index": "a",
|
|
"min_max_arg": "d",
|
|
"min_aggregate": true,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 8,
|
|
"cost": 2.2,
|
|
"key_parts_used_for_access": ["a", "b", "c"],
|
|
"ranges": ["(2,3) <= (b,c) <= (2,3)"]
|
|
},
|
|
"rows_for_plan": 8,
|
|
"cost_for_plan": 2.2,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "index_merge",
|
|
"resulting_rows": 8,
|
|
"cost": 2.2,
|
|
"chosen": true,
|
|
"use_tmp_table": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "index_merge",
|
|
"records": 8,
|
|
"cost": 2.2,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 8,
|
|
"cost_for_plan": 3.8,
|
|
"cost_for_sorting": 8,
|
|
"estimated_join_cardinality": 8
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.b = 2 and t1.c = 3",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": "t1.b = 2 and t1.c = 3"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": []
|
|
},
|
|
{
|
|
"prepare_sum_aggregators": {
|
|
"function": "min(t1.d)",
|
|
"aggregator_type": "simple"
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
DROP TABLE t1;
|
|
CREATE TABLE t1 (id INT NOT NULL, a DATE, KEY(id,a));
|
|
INSERT INTO t1 values (1,'2001-01-01'),(1,'2001-01-02'),
|
|
(1,'2001-01-03'),(1,'2001-01-04'),
|
|
(2,'2001-01-01'),(2,'2001-01-02'),
|
|
(2,'2001-01-03'),(2,'2001-01-04'),
|
|
(3,'2001-01-01'),(3,'2001-01-02'),
|
|
(3,'2001-01-03'),(3,'2001-01-04'),
|
|
(4,'2001-01-01'),(4,'2001-01-02'),
|
|
(4,'2001-01-03'),(4,'2001-01-04');
|
|
set optimizer_trace='enabled=on';
|
|
EXPLAIN SELECT id,MIN(a),MAX(a) FROM t1 WHERE a>=20010104e0 GROUP BY id;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL id 8 NULL 9 Using where; Using index for group-by
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
EXPLAIN SELECT id,MIN(a),MAX(a) FROM t1 WHERE a>=20010104e0 GROUP BY id {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.`id` AS `id`,min(t1.a) AS `MIN(a)`,max(t1.a) AS `MAX(a)` from t1 where t1.a >= 20010104e0 group by t1.`id`"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.a >= 20010104e0",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "t1.a >= 20010104e0"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "t1.a >= 20010104e0"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "t1.a >= 20010104e0"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 16,
|
|
"cost": 7.23125
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "id",
|
|
"usable": true,
|
|
"key_parts": ["id", "a"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "id",
|
|
"cost": 4.21171589,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"potential_group_range_indexes": [
|
|
{
|
|
"index": "id",
|
|
"covering": true,
|
|
"ranges": ["(2001-01-04) <= (a)"],
|
|
"rows": 9,
|
|
"cost": 2.35
|
|
}
|
|
]
|
|
},
|
|
"best_group_range_summary": {
|
|
"type": "index_group",
|
|
"index": "id",
|
|
"min_max_arg": "a",
|
|
"min_aggregate": true,
|
|
"max_aggregate": true,
|
|
"distinct_aggregate": false,
|
|
"rows": 9,
|
|
"cost": 2.35,
|
|
"key_parts_used_for_access": ["id"],
|
|
"ranges": ["(2001-01-04) <= (a)"],
|
|
"chosen": true
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "index_group",
|
|
"index": "id",
|
|
"min_max_arg": "a",
|
|
"min_aggregate": true,
|
|
"max_aggregate": true,
|
|
"distinct_aggregate": false,
|
|
"rows": 9,
|
|
"cost": 2.35,
|
|
"key_parts_used_for_access": ["id"],
|
|
"ranges": ["(2001-01-04) <= (a)"]
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 2.35,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "index_merge",
|
|
"resulting_rows": 9,
|
|
"cost": 2.35,
|
|
"chosen": true,
|
|
"use_tmp_table": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "index_merge",
|
|
"records": 9,
|
|
"cost": 2.35,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 4.15,
|
|
"cost_for_sorting": 9,
|
|
"estimated_join_cardinality": 9
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.a >= 20010104e0",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": "t1.a >= 20010104e0"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": []
|
|
},
|
|
{
|
|
"prepare_sum_aggregators": {
|
|
"function": "min(t1.a)",
|
|
"aggregator_type": "simple"
|
|
}
|
|
},
|
|
{
|
|
"prepare_sum_aggregators": {
|
|
"function": "max(t1.a)",
|
|
"aggregator_type": "simple"
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
EXPLAIN SELECT * FROM t1 WHERE a = 20010104e0 GROUP BY id;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range NULL id 8 NULL 9 Using where; Using index for group-by
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
EXPLAIN SELECT * FROM t1 WHERE a = 20010104e0 GROUP BY id {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.`id` AS `id`,t1.a AS a from t1 where t1.a = 20010104e0 group by t1.`id`"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.a = 20010104e0",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "t1.a = 20010104e0"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "t1.a = 20010104e0"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "t1.a = 20010104e0"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 16,
|
|
"cost": 7.23125
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "id",
|
|
"usable": true,
|
|
"key_parts": ["id", "a"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "id",
|
|
"cost": 4.21171589,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"potential_group_range_indexes": [
|
|
{
|
|
"index": "id",
|
|
"covering": true,
|
|
"ranges": ["(2001-01-04) <= (a) <= (2001-01-04)"],
|
|
"rows": 9,
|
|
"cost": 2.35
|
|
}
|
|
]
|
|
},
|
|
"best_group_range_summary": {
|
|
"type": "index_group",
|
|
"index": "id",
|
|
"min_max_arg": null,
|
|
"min_aggregate": false,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 9,
|
|
"cost": 2.35,
|
|
"key_parts_used_for_access": ["id", "a"],
|
|
"ranges": ["(2001-01-04) <= (a) <= (2001-01-04)"],
|
|
"chosen": true
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "index_group",
|
|
"index": "id",
|
|
"min_max_arg": null,
|
|
"min_aggregate": false,
|
|
"max_aggregate": false,
|
|
"distinct_aggregate": false,
|
|
"rows": 9,
|
|
"cost": 2.35,
|
|
"key_parts_used_for_access": ["id", "a"],
|
|
"ranges": ["(2001-01-04) <= (a) <= (2001-01-04)"]
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 2.35,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "index_merge",
|
|
"resulting_rows": 9,
|
|
"cost": 2.35,
|
|
"chosen": true,
|
|
"use_tmp_table": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "index_merge",
|
|
"records": 9,
|
|
"cost": 2.35,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 4.15,
|
|
"cost_for_sorting": 9,
|
|
"estimated_join_cardinality": 9
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.a = 20010104e0",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": "t1.a = 20010104e0"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": []
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1;
|
|
#
|
|
# Late ORDER BY optimization
|
|
#
|
|
create table ten(a int);
|
|
insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table one_k(a int primary key);
|
|
insert into one_k select A.a + B.a* 10 + C.a * 100 from ten A, ten B, ten C;
|
|
create table t1 (
|
|
pk int not null,
|
|
a int,
|
|
b int,
|
|
c int,
|
|
filler char(100),
|
|
KEY a_a(c),
|
|
KEY a_c(a,c),
|
|
KEY a_b(a,b)
|
|
);
|
|
insert into t1
|
|
select a, a,a,a, 'filler-dataaa' from test.one_k;
|
|
update t1 set a=1 where pk between 0 and 180;
|
|
update t1 set b=2 where pk between 0 and 20;
|
|
analyze table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
set optimizer_trace='enabled=on';
|
|
explain select * from t1 where a=1 and b=2 order by c limit 1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range a_c,a_b a_c 5 NULL 180 Using where
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 where a=1 and b=2 order by c limit 1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.pk AS pk,t1.a AS a,t1.b AS b,t1.c AS c,t1.filler AS filler from t1 where t1.a = 1 and t1.b = 2 order by t1.c limit 1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.a = 1 and t1.b = 2",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "multiple equal(1, t1.a) and multiple equal(2, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "multiple equal(1, t1.a) and multiple equal(2, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(1, t1.a) and multiple equal(2, t1.b)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "1",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "1",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "b",
|
|
"equals": "2",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 1000,
|
|
"cost": 232.5644531
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a_a",
|
|
"usable": false,
|
|
"cause": "not applicable"
|
|
},
|
|
{
|
|
"index": "a_c",
|
|
"usable": true,
|
|
"key_parts": ["a", "c"]
|
|
},
|
|
{
|
|
"index": "a_b",
|
|
"usable": true,
|
|
"key_parts": ["a", "b"]
|
|
}
|
|
],
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "a_c",
|
|
"ranges": ["(1) <= (a) <= (1)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 180,
|
|
"cost": 216.2943776,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"index": "a_b",
|
|
"ranges": ["(1,2) <= (a,b) <= (1,2)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 21,
|
|
"cost": 25.36242739,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "no group by or distinct"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "a_b",
|
|
"rows": 21,
|
|
"ranges": ["(1,2) <= (a,b) <= (1,2)"]
|
|
},
|
|
"rows_for_plan": 21,
|
|
"cost_for_plan": 25.36242739,
|
|
"chosen": true
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"rowid_filters": [
|
|
{
|
|
"key": "a_b",
|
|
"build_cost": 0.886777098,
|
|
"rows": 21
|
|
},
|
|
{
|
|
"key": "a_c",
|
|
"build_cost": 10.52169992,
|
|
"rows": 180
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"selectivity_for_indexes": [
|
|
{
|
|
"index_name": "a_b",
|
|
"selectivity_from_index": 0.021
|
|
}
|
|
],
|
|
"selectivity_for_columns": [
|
|
{
|
|
"column_name": "a",
|
|
"ranges": ["1 <= a <= 1"],
|
|
"selectivity_from_histogram": 0.1796875
|
|
},
|
|
{
|
|
"column_name": "b",
|
|
"ranges": ["2 <= b <= 2"],
|
|
"selectivity_from_histogram": 0.015625
|
|
}
|
|
],
|
|
"cond_selectivity": 0.021
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a_c",
|
|
"used_range_estimates": true,
|
|
"rowid_filter_skipped": "worst/max seeks clipping",
|
|
"rows": 180,
|
|
"cost": 180.2743776,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a_b",
|
|
"used_range_estimates": true,
|
|
"rows": 21,
|
|
"cost": 21.14242739,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"type": "scan",
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 21,
|
|
"cost": 21.14242739,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 21,
|
|
"cost_for_plan": 25.34242739,
|
|
"estimated_join_cardinality": 21
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.a = 1 and t1.b = 2",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"test_if_skip_sort_order": [
|
|
{
|
|
"reconsidering_access_paths_for_index_ordering": {
|
|
"clause": "ORDER BY",
|
|
"fanout": 1,
|
|
"read_time": 21.14342739,
|
|
"table": "t1",
|
|
"rows_estimation": 21,
|
|
"possible_keys": [
|
|
{
|
|
"index": "a_a",
|
|
"can_resolve_order": true,
|
|
"updated_limit": 47,
|
|
"index_scan_time": 47,
|
|
"usable": false,
|
|
"cause": "cost"
|
|
},
|
|
{
|
|
"index": "a_c",
|
|
"can_resolve_order": true,
|
|
"updated_limit": 47,
|
|
"range_scan_time": 4.331020747,
|
|
"index_scan_time": 4.331020747,
|
|
"records": 180,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"index": "a_b",
|
|
"can_resolve_order": false,
|
|
"cause": "not usable index for the query"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 1000,
|
|
"cost": 1.79769e308
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a_a",
|
|
"usable": false,
|
|
"cause": "not applicable"
|
|
},
|
|
{
|
|
"index": "a_c",
|
|
"usable": true,
|
|
"key_parts": ["a", "c"]
|
|
},
|
|
{
|
|
"index": "a_b",
|
|
"usable": false,
|
|
"cause": "not applicable"
|
|
}
|
|
],
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "a_c",
|
|
"ranges": ["(1) <= (a) <= (1)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 180,
|
|
"cost": 216.2943776,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "no group by or distinct"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "a_c",
|
|
"rows": 180,
|
|
"ranges": ["(1) <= (a) <= (1)"]
|
|
},
|
|
"rows_for_plan": 180,
|
|
"cost_for_plan": 216.2943776,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1,ten,one_k;
|
|
#
|
|
# TABLE ELIMINATION
|
|
#
|
|
create table t1 (a int);
|
|
insert into t1 values (0),(1),(2),(3);
|
|
create table t0 as select * from t1;
|
|
create table t2 (a int primary key, b int)
|
|
as select a, a as b from t1 where a in (1,2);
|
|
create table t3 (a int primary key, b int)
|
|
as select a, a as b from t1 where a in (1,3);
|
|
set optimizer_trace='enabled=on';
|
|
analyze table t1;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
analyze table t2;
|
|
Table Op Msg_type Msg_text
|
|
test.t2 analyze status Engine-independent statistics collected
|
|
test.t2 analyze status OK
|
|
analyze table t3;
|
|
Table Op Msg_type Msg_text
|
|
test.t3 analyze status Engine-independent statistics collected
|
|
test.t3 analyze status OK
|
|
# table t2 should be eliminated
|
|
explain
|
|
select t1.a from t1 left join t2 on t1.a=t2.a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain
|
|
select t1.a from t1 left join t2 on t1.a=t2.a {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.a AS a from (t1 left join t2 on(t1.a = t2.a))"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"row_may_be_null": true,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": ["0"]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t2",
|
|
"field": "a",
|
|
"equals": "t1.a",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"eliminated_tables": ["t2"]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 4,
|
|
"cost": 2.006835938
|
|
}
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"rows": 1,
|
|
"cost": 1,
|
|
"table_type": "const"
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": ["t2"],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 4,
|
|
"cost": 2.006835938,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 4,
|
|
"cost": 2.006835938,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 2.806835937,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t2", "t1"]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
# no tables should be eliminated
|
|
explain select * from t1 left join t2 on t2.a=t1.a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
|
|
1 SIMPLE t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using where
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 left join t2 on t2.a=t1.a {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.a AS a,t2.a AS a,t2.b AS b from (t1 left join t2 on(t2.a = t1.a))"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"row_may_be_null": true,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": ["0"]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t2",
|
|
"field": "a",
|
|
"equals": "t1.a",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"eliminated_tables": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 4,
|
|
"cost": 2.006835938
|
|
}
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"table_scan": {
|
|
"rows": 2,
|
|
"cost": 2.004394531
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 4,
|
|
"cost": 2.006835938,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 4,
|
|
"cost": 2.006835938,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 2.806835937,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "eq_ref",
|
|
"index": "PRIMARY",
|
|
"rows": 1,
|
|
"cost": 4,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 8.017578125,
|
|
"chosen": false
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "eq_ref",
|
|
"records": 1,
|
|
"cost": 4,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 7.606835937,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1", "t2"]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"attached": "trigcond(trigcond(t1.a is not null))"
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
# multiple tables are eliminated
|
|
explain select t1.a from t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 4
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select t1.a from t1 left join (t2 join t3 on t2.b=t3.b) on t2.a=t1.a and t3.a=t1.a {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.a AS a from (t1 left join (t2 join t3 on(t2.b = t3.b)) on(t2.a = t1.a and t3.a = t1.a))"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"row_may_be_null": true,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": ["0"]
|
|
},
|
|
{
|
|
"table": "t3",
|
|
"row_may_be_null": true,
|
|
"map_bit": 2,
|
|
"depends_on_map_bits": ["0"]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t2",
|
|
"field": "a",
|
|
"equals": "t1.a",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"field": "a",
|
|
"equals": "t3.a",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t3",
|
|
"field": "a",
|
|
"equals": "t2.a",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t3",
|
|
"field": "a",
|
|
"equals": "t1.a",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"eliminated_tables": ["t3", "t2"]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 4,
|
|
"cost": 2.006835938
|
|
}
|
|
},
|
|
{
|
|
"table": "t2",
|
|
"rows": 1,
|
|
"cost": 1,
|
|
"table_type": "const"
|
|
},
|
|
{
|
|
"table": "t3",
|
|
"rows": 1,
|
|
"cost": 1,
|
|
"table_type": "const"
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": ["t3", "t2"],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 4,
|
|
"cost": 2.006835938,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 4,
|
|
"cost": 2.006835938,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 2.806835937,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t3", "t2", "t1"]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t0, t1, t2, t3;
|
|
#
|
|
# IN subquery to sem-join is traced
|
|
#
|
|
create table t0 (a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1(a int, b int);
|
|
insert into t1 values (0,0),(1,1),(2,2);
|
|
create table t2 as select * from t1;
|
|
create table t11(a int, b int);
|
|
create table t10 (pk int, a int);
|
|
insert into t10 select a,a from t0;
|
|
create table t12 like t10;
|
|
insert into t12 select * from t10;
|
|
analyze table t1,t10;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
test.t10 analyze status Engine-independent statistics collected
|
|
test.t10 analyze status OK
|
|
set optimizer_trace='enabled=on';
|
|
explain extended select * from t1 where a in (select pk from t10);
|
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00
|
|
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1 100.00
|
|
2 MATERIALIZED t10 ALL NULL NULL NULL NULL 10 100.00
|
|
Warnings:
|
|
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` semi join (`test`.`t10`) where 1
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain extended select * from t1 where a in (select pk from t10) {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#2 */ select t10.pk from t10"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select t1.a AS a,t1.b AS b from t1 where t1.a in (/* select#2 */ select t10.pk from t10)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "1 and t1.a = t10.pk",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "1 and multiple equal(t1.a, t10.pk)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "1 and multiple equal(t1.a, t10.pk)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(t1.a, t10.pk)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t10",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.006591797
|
|
}
|
|
},
|
|
{
|
|
"table": "t10",
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 2.021972656
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"execution_plan_for_potential_materialization": {
|
|
"steps": [
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t10",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.021972656,
|
|
"estimated_join_cardinality": 10
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.006591797,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.006591797,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.606591797,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t10",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 30,
|
|
"cost_for_plan": 10.62856445,
|
|
"semijoin_strategy_choice": [
|
|
{
|
|
"strategy": "FirstMatch",
|
|
"records": 3,
|
|
"read_time": 10.62856445
|
|
},
|
|
{
|
|
"strategy": "SJ-Materialization",
|
|
"records": 3,
|
|
"read_time": 5.278564453
|
|
},
|
|
{
|
|
"strategy": "DuplicateWeedout",
|
|
"records": 3,
|
|
"read_time": 27.12856445
|
|
},
|
|
{
|
|
"chosen_strategy": "SJ-Materialization"
|
|
}
|
|
],
|
|
"estimated_join_cardinality": 3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t10",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.021972656,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"fix_semijoin_strategies_for_picked_join_order": [
|
|
{
|
|
"semi_join_strategy": "SJ-Materialization",
|
|
"join_order": [
|
|
{
|
|
"table": "t10"
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1", "<subquery2>"]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t10",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "<subquery2>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t0,t1,t11,t10,t12,t2;
|
|
#
|
|
# Selectivities for columns and indexes.
|
|
#
|
|
create table t0 (a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (
|
|
pk int,
|
|
a int,
|
|
b int,
|
|
key pk(pk),
|
|
key pk_a(pk,a),
|
|
key pk_a_b(pk,a,b));
|
|
insert into t1 select a,a,a from t0;
|
|
ANALYZE TABLE t1 PERSISTENT FOR COLUMNS (a,b) INDEXES ();
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status Table is already up to date
|
|
set @save_optimizer_use_condition_selectivity=@@optimizer_use_condition_selectivity;
|
|
set @save_use_stat_tables= @@use_stat_tables;
|
|
set @@optimizer_use_condition_selectivity=4;
|
|
set @@use_stat_tables= PREFERABLY;
|
|
set optimizer_trace='enabled=on';
|
|
explain select * from t1 where pk = 2 and a=5 and b=1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref pk,pk_a,pk_a_b pk_a_b 15 const,const,const 1 Using index
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 where pk = 2 and a=5 and b=1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select t1.pk AS pk,t1.a AS a,t1.b AS b from t1 where t1.pk = 2 and t1.a = 5 and t1.b = 1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t1.pk = 2 and t1.a = 5 and t1.b = 1",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "multiple equal(2, t1.pk) and multiple equal(5, t1.a) and multiple equal(1, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "multiple equal(2, t1.pk) and multiple equal(5, t1.a) and multiple equal(1, t1.b)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(2, t1.pk) and multiple equal(5, t1.a) and multiple equal(1, t1.b)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t1",
|
|
"field": "pk",
|
|
"equals": "2",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "pk",
|
|
"equals": "2",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "5",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "pk",
|
|
"equals": "2",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "5",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "b",
|
|
"equals": "1",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 6.031738281
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "pk",
|
|
"usable": true,
|
|
"key_parts": ["pk"]
|
|
},
|
|
{
|
|
"index": "pk_a",
|
|
"usable": true,
|
|
"key_parts": ["pk", "a"]
|
|
},
|
|
{
|
|
"index": "pk_a_b",
|
|
"usable": true,
|
|
"key_parts": ["pk", "a", "b"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "pk_a_b",
|
|
"cost": 3.010739566,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "pk",
|
|
"ranges": ["(2) <= (pk) <= (2)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"index": "pk_a",
|
|
"ranges": ["(2,5) <= (pk,a) <= (2,5)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345829876,
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
},
|
|
{
|
|
"index": "pk_a_b",
|
|
"ranges": ["(2,5,1) <= (pk,a,b) <= (2,5,1)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 1,
|
|
"cost": 0.346073957,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect": {
|
|
"intersecting_indexes": [
|
|
{
|
|
"index": "pk",
|
|
"index_scan_cost": 1.000585794,
|
|
"cumulated_index_scan_cost": 1.000585794,
|
|
"disk_sweep_cost": 0.90078125,
|
|
"cumulative_total_cost": 1.901367044,
|
|
"usable": true,
|
|
"matching_rows_now": 1,
|
|
"intersect_covering_with_this_index": false,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"index": "pk_a",
|
|
"usable": false,
|
|
"cause": "does not reduce cost of intersect"
|
|
},
|
|
{
|
|
"index": "pk_a_b",
|
|
"usable": false,
|
|
"cause": "does not reduce cost of intersect"
|
|
}
|
|
],
|
|
"clustered_pk": {
|
|
"clustered_pk_added_to_intersect": false,
|
|
"cause": "no clustered pk index"
|
|
},
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "no group by or distinct"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "pk_a_b",
|
|
"rows": 1,
|
|
"ranges": ["(2,5,1) <= (pk,a,b) <= (2,5,1)"]
|
|
},
|
|
"rows_for_plan": 1,
|
|
"cost_for_plan": 0.346073957,
|
|
"chosen": true
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"rowid_filters": [
|
|
{
|
|
"key": "pk",
|
|
"build_cost": 0.130585794,
|
|
"rows": 1
|
|
},
|
|
{
|
|
"key": "pk_a",
|
|
"build_cost": 0.130829876,
|
|
"rows": 1
|
|
},
|
|
{
|
|
"key": "pk_a_b",
|
|
"build_cost": 0.131073957,
|
|
"rows": 1
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"selectivity_for_indexes": [
|
|
{
|
|
"index_name": "pk_a_b",
|
|
"selectivity_from_index": 0.1
|
|
}
|
|
],
|
|
"selectivity_for_columns": [
|
|
{
|
|
"column_name": "a",
|
|
"ranges": ["5 <= a <= 5"],
|
|
"selectivity_from_histogram": 0.1
|
|
},
|
|
{
|
|
"column_name": "b",
|
|
"ranges": ["1 <= b <= 1"],
|
|
"selectivity_from_histogram": 0.1
|
|
}
|
|
],
|
|
"cond_selectivity": 0.1
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "pk",
|
|
"used_range_estimates": true,
|
|
"rows": 1,
|
|
"cost": 1.125585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "ref",
|
|
"index": "pk_a",
|
|
"used_range_estimates": true,
|
|
"rows": 1,
|
|
"cost": 1.125829876,
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
},
|
|
{
|
|
"access_type": "ref",
|
|
"index": "pk_a_b",
|
|
"used_range_estimates": true,
|
|
"rows": 1,
|
|
"cost": 0.126073957,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"type": "scan",
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 0.126073957,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 1,
|
|
"cost_for_plan": 0.326073957,
|
|
"estimated_join_cardinality": 1
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.pk = 2 and t1.a = 5 and t1.b = 1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
set @@optimizer_use_condition_selectivity=@save_optimizer_use_condition_selectivity;
|
|
set @@use_stat_tables= @save_use_stat_tables;
|
|
drop table t0,t1;
|
|
set optimizer_trace="enabled=off";
|
|
#
|
|
# Tests added to show that sub-statements are not traced
|
|
#
|
|
create table t1(a int);
|
|
insert into t1 values (1),(2),(3),(4);
|
|
create table t2(a int);
|
|
insert into t2 values (1),(2),(3),(4);
|
|
create function f1(a int) returns int
|
|
begin
|
|
declare a int default 0;
|
|
set a= a+ (select count(*) from t2);
|
|
return a;
|
|
end|
|
|
create function f2(a int) returns int
|
|
begin
|
|
declare a int default 0;
|
|
select count(*) from t2 into a;
|
|
return a;
|
|
end|
|
|
Warnings:
|
|
Warning 1287 '<select expression> INTO <destination>;' is deprecated and will be removed in a future release. Please use 'SELECT <select list> INTO <destination> FROM...' instead
|
|
set optimizer_trace='enabled=on';
|
|
select f1(a) from t1;
|
|
f1(a)
|
|
4
|
|
4
|
|
4
|
|
4
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
select f1(a) from t1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select f1(t1.a) AS `f1(a)` from t1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 4,
|
|
"cost": 2.006835938
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 4,
|
|
"cost": 2.006835938,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 4,
|
|
"cost": 2.006835938,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 2.806835937,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
select f2(a) from t1;
|
|
f2(a)
|
|
4
|
|
4
|
|
4
|
|
4
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
select f2(a) from t1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select f2(t1.a) AS `f2(a)` from t1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 4,
|
|
"cost": 2.006835938
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 4,
|
|
"cost": 2.006835938,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 4,
|
|
"cost": 2.006835938,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 2.806835937,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1,t2;
|
|
drop function f1;
|
|
drop function f2;
|
|
set optimizer_trace='enabled=off';
|
|
#
|
|
# MDEV-18489: Limit the memory used by the optimizer trace
|
|
#
|
|
create table t1 (a int);
|
|
insert into t1 values (1),(2);
|
|
set optimizer_trace='enabled=on';
|
|
set @save_optimizer_trace_max_mem_size= @@optimizer_trace_max_mem_size;
|
|
select * from t1;
|
|
a
|
|
1
|
|
2
|
|
select length(trace) from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
length(trace)
|
|
2183
|
|
set optimizer_trace_max_mem_size=100;
|
|
select * from t1;
|
|
a
|
|
1
|
|
2
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
select * from t1 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
2083 0
|
|
set optimizer_trace_max_mem_size=0;
|
|
select * from t1;
|
|
a
|
|
1
|
|
2
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
select * from t1 2183 0
|
|
drop table t1;
|
|
set optimizer_trace='enabled=off';
|
|
set @@optimizer_trace_max_mem_size= @save_optimizer_trace_max_mem_size;
|
|
#
|
|
# MDEV-18527: Optimizer trace for DELETE query shows table:null
|
|
#
|
|
create table ten(a int);
|
|
insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t0 (a int, b int);
|
|
insert into t0 select a,a from ten;
|
|
alter table t0 add key(a);
|
|
set optimizer_trace=1;
|
|
explain delete from t0 where t0.a<3;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t0 range a a 5 NULL 3 Using where
|
|
select * from information_schema.optimizer_trace;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain delete from t0 where t0.a<3 {
|
|
"steps": [
|
|
{
|
|
"table": "t0",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 6.021972656
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"usable": true,
|
|
"key_parts": ["a"]
|
|
}
|
|
],
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "a",
|
|
"ranges": ["(NULL) < (a) < (3)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 3,
|
|
"cost": 3.746757383,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "no join"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "a",
|
|
"rows": 3,
|
|
"ranges": ["(NULL) < (a) < (3)"]
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 3.746757383,
|
|
"chosen": true
|
|
}
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table ten,t0;
|
|
set optimizer_trace='enabled=off';
|
|
#
|
|
# MDEV-18528: Optimizer trace support for multi-table UPDATE and DELETE
|
|
#
|
|
set optimizer_trace=1;
|
|
create table ten(a int);
|
|
insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t0 (a int, b int);
|
|
insert into t0 select a,a from ten;
|
|
alter table t0 add key(a);
|
|
create table t1 like t0;
|
|
insert into t1 select * from t0;
|
|
explain delete t0,t1 from t0, t1 where t0.a=t1.a and t1.a<3;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t0 range a a 5 NULL 3 Using where
|
|
1 SIMPLE t1 ref a a 5 test.t0.a 1
|
|
select * from information_schema.optimizer_trace;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain delete t0,t1 from t0, t1 where t0.a=t1.a and t1.a<3 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "delete from t0,t1 using t0 join t1 where t0.a = t1.a and t1.a < 3"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "t0.a = t1.a and t1.a < 3",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "t1.a < 3 and multiple equal(t0.a, t1.a)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "t1.a < 3 and multiple equal(t0.a, t1.a)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "t1.a < 3 and multiple equal(t0.a, t1.a)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t0",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": [
|
|
{
|
|
"table": "t0",
|
|
"field": "a",
|
|
"equals": "t1.a",
|
|
"null_rejecting": true
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"field": "a",
|
|
"equals": "t0.a",
|
|
"null_rejecting": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t0",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 6.021972656
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"usable": true,
|
|
"key_parts": ["a"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "a",
|
|
"cost": 3.005857945,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "a",
|
|
"ranges": ["(NULL) < (a) < (3)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 3,
|
|
"cost": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "not single_table"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "a",
|
|
"rows": 3,
|
|
"ranges": ["(NULL) < (a) < (3)"]
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"selectivity_for_indexes": [
|
|
{
|
|
"index_name": "a",
|
|
"selectivity_from_index": 0.3
|
|
}
|
|
],
|
|
"selectivity_for_columns": [],
|
|
"cond_selectivity": 0.3
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"range_analysis": {
|
|
"table_scan": {
|
|
"rows": 10,
|
|
"cost": 6.021972656
|
|
},
|
|
"potential_range_indexes": [
|
|
{
|
|
"index": "a",
|
|
"usable": true,
|
|
"key_parts": ["a"]
|
|
}
|
|
],
|
|
"best_covering_index_scan": {
|
|
"index": "a",
|
|
"cost": 3.005857945,
|
|
"chosen": true
|
|
},
|
|
"setup_range_conditions": [],
|
|
"analyzing_range_alternatives": {
|
|
"range_scan_alternatives": [
|
|
{
|
|
"index": "a",
|
|
"ranges": ["(NULL) < (a) < (3)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 3,
|
|
"cost": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect": {
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union": []
|
|
},
|
|
"group_index_range": {
|
|
"chosen": false,
|
|
"cause": "not single_table"
|
|
},
|
|
"chosen_range_access_summary": {
|
|
"range_access_plan": {
|
|
"type": "range_scan",
|
|
"index": "a",
|
|
"rows": 3,
|
|
"ranges": ["(NULL) < (a) < (3)"]
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
}
|
|
},
|
|
{
|
|
"selectivity_for_indexes": [
|
|
{
|
|
"index_name": "a",
|
|
"selectivity_from_index": 0.3
|
|
}
|
|
],
|
|
"selectivity_for_columns": [],
|
|
"cond_selectivity": 0.3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t0",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "range",
|
|
"resulting_rows": 3,
|
|
"cost": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "range",
|
|
"records": 3,
|
|
"cost": 0.746757383,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 1.346757383,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t0"],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not better than ref estimates",
|
|
"rows": 1,
|
|
"cost": 3.001757383,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"type": "scan",
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 3.001757383,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 4.948514767,
|
|
"estimated_join_cardinality": 3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "range",
|
|
"resulting_rows": 3,
|
|
"cost": 0.746757383,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "range",
|
|
"records": 3,
|
|
"cost": 0.746757383,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 1.346757383,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t0",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not better than ref estimates",
|
|
"rowid_filter_skipped": "worst/max seeks clipping",
|
|
"rows": 2,
|
|
"cost": 3.003514767,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"type": "scan",
|
|
"chosen": false,
|
|
"cause": "cost"
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "ref",
|
|
"records": 2,
|
|
"cost": 3.003514767,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 6,
|
|
"cost_for_plan": 5.55027215,
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t0", "t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t1.a = t0.a and t0.a < 3",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t0",
|
|
"attached": "t0.a < 3 and t0.a is not null"
|
|
},
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table ten,t0,t1;
|
|
set optimizer_trace='enabled=off';
|
|
#
|
|
# Merged to Materialized for derived tables
|
|
#
|
|
set optimizer_trace=1;
|
|
create table t1 (a int);
|
|
insert into t1 values (1),(2),(3);
|
|
explain select * from (select rand() from t1)q;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
|
|
2 DERIVED t1 ALL NULL NULL NULL NULL 3
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from (select rand() from t1)q {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"derived": {
|
|
"table": "q",
|
|
"select_id": 2,
|
|
"algorithm": "materialized"
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#2 */ select rand() AS `rand()` from t1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select q.`rand()` AS `rand()` from (/* select#2 */ select rand() AS `rand()` from t1) q"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"estimated_join_cardinality": 3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "<derived2>",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "<derived2>",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 3
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "<derived2>",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 3,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 3,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 3.6,
|
|
"estimated_join_cardinality": 3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["<derived2>"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "<derived2>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_execution": {
|
|
"select_id": 2,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
drop table t1;
|
|
set optimizer_trace='enabled=off';
|
|
#
|
|
# Semi-join nest
|
|
#
|
|
set optimizer_trace=1;
|
|
create table t1 (a int);
|
|
insert into t1 values (1),(2),(3);
|
|
create table t2(a int);
|
|
insert into t2 values (1),(2),(3),(1),(2),(3),(1),(2),(3);
|
|
set @save_optimizer_switch= @@optimizer_switch;
|
|
explain select * from t1 where a in (select t_inner_1.a from t1 t_inner_1, t1 t_inner_2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3
|
|
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1
|
|
2 MATERIALIZED t_inner_1 ALL NULL NULL NULL NULL 3
|
|
2 MATERIALIZED t_inner_2 ALL NULL NULL NULL NULL 3 Using join buffer (flat, BNL join)
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 where a in (select t_inner_1.a from t1 t_inner_1, t1 t_inner_2) {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#2 */ select t_inner_1.a from t1 t_inner_1 join t1 t_inner_2"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select t1.a AS a from t1 where t1.a in (/* select#2 */ select t_inner_1.a from t1 t_inner_1 join t1 t_inner_2)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "1 and t1.a = t_inner_1.a",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "1 and multiple equal(t1.a, t_inner_1.a)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "1 and multiple equal(t1.a, t_inner_1.a)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(t1.a, t_inner_1.a)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 2,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"execution_plan_for_potential_materialization": {
|
|
"steps": [
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_inner_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"estimated_join_cardinality": 9
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t1", "t_inner_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 13.81538086,
|
|
"semijoin_strategy_choice": [
|
|
{
|
|
"strategy": "FirstMatch",
|
|
"records": 3,
|
|
"read_time": 33.86665039
|
|
},
|
|
{
|
|
"strategy": "SJ-Materialization",
|
|
"records": 3,
|
|
"read_time": 7.215380859
|
|
},
|
|
{
|
|
"strategy": "DuplicateWeedout",
|
|
"records": 3,
|
|
"read_time": 18.31538086
|
|
},
|
|
{
|
|
"chosen_strategy": "SJ-Materialization"
|
|
}
|
|
],
|
|
"estimated_join_cardinality": 3
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": ["t1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"fix_semijoin_strategies_for_picked_join_order": [
|
|
{
|
|
"semi_join_strategy": "SJ-Materialization",
|
|
"join_order": [
|
|
{
|
|
"table": "t_inner_1"
|
|
},
|
|
{
|
|
"table": "t_inner_2"
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t1", "<subquery2>"]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "<subquery2>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
# with Firstmatch, mostly for tracing fix_semijoin_strategies_for_picked_join_order
|
|
set optimizer_switch='materialization=off';
|
|
explain select * from t1 t_outer_1,t2 t_outer_2 where t_outer_1.a in (select t_inner_1.a from t2 t_inner_2, t1 t_inner_1) and
|
|
t_outer_2.a in (select t_inner_3.a from t2 t_inner_3, t1 t_inner_4);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t_outer_1 ALL NULL NULL NULL NULL 3
|
|
1 PRIMARY t_inner_1 ALL NULL NULL NULL NULL 3 Using where; Start temporary; Using join buffer (flat, BNL join)
|
|
1 PRIMARY t_inner_2 ALL NULL NULL NULL NULL 9 End temporary; Using join buffer (incremental, BNL join)
|
|
1 PRIMARY t_inner_4 ALL NULL NULL NULL NULL 3 Start temporary; Using join buffer (incremental, BNL join)
|
|
1 PRIMARY t_outer_2 ALL NULL NULL NULL NULL 9 Using join buffer (incremental, BNL join)
|
|
1 PRIMARY t_inner_3 ALL NULL NULL NULL NULL 9 Using where; End temporary; Using join buffer (incremental, BNL join)
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 t_outer_1,t2 t_outer_2 where t_outer_1.a in (select t_inner_1.a from t2 t_inner_2, t1 t_inner_1) and
|
|
t_outer_2.a in (select t_inner_3.a from t2 t_inner_3, t1 t_inner_4) {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#2 */ select t_inner_1.a from t2 t_inner_2 join t1 t_inner_1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 3,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#3 */ select t_inner_3.a from t2 t_inner_3 join t1 t_inner_4"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select t_outer_1.a AS a,t_outer_2.a AS a from t1 t_outer_1 join t2 t_outer_2 where t_outer_1.a in (/* select#2 */ select t_inner_1.a from t2 t_inner_2 join t1 t_inner_1) and t_outer_2.a in (/* select#3 */ select t_inner_3.a from t2 t_inner_3 join t1 t_inner_4)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "1 and 1 and t_outer_1.a = t_inner_1.a and t_outer_2.a = t_inner_3.a",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "1 and 1 and multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "1 and 1 and multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 2,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 3,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"row_may_be_null": false,
|
|
"map_bit": 4,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"row_may_be_null": false,
|
|
"map_bit": 5,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"execution_plan_for_potential_materialization": {
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_outer_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 24.62563477,
|
|
"semijoin_strategy_choice": [
|
|
{
|
|
"strategy": "FirstMatch",
|
|
"records": 3,
|
|
"read_time": 44.75893555
|
|
},
|
|
{
|
|
"strategy": "DuplicateWeedout",
|
|
"records": 3,
|
|
"read_time": 37.22563477
|
|
},
|
|
{
|
|
"chosen_strategy": "DuplicateWeedout"
|
|
}
|
|
],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1", "t_inner_2"],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 44.64101563,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_outer_2"
|
|
],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 62.84614258,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_outer_2",
|
|
"t_inner_4"
|
|
],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 729,
|
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"cost_for_plan": 210.6615234,
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"t_inner_3"
|
|
]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "t_inner_1.a = t_outer_1.a and t_inner_3.a = t_outer_2.a",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"attached": "t_inner_1.a = t_outer_1.a"
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"attached": "t_inner_3.a = t_outer_2.a"
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
set optimizer_switch='materialization=on';
|
|
explain select * from t1 t_outer_1,t2 t_outer_2 where t_outer_1.a in (select t_inner_1.a from t2 t_inner_2, t1 t_inner_1) and
|
|
t_outer_2.a in (select t_inner_3.a from t2 t_inner_3, t1 t_inner_4);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t_outer_1 ALL NULL NULL NULL NULL 3
|
|
1 PRIMARY <subquery2> eq_ref distinct_key distinct_key 4 func 1
|
|
1 PRIMARY t_outer_2 ALL NULL NULL NULL NULL 9 Using join buffer (flat, BNL join)
|
|
1 PRIMARY <subquery3> eq_ref distinct_key distinct_key 4 func 1
|
|
2 MATERIALIZED t_inner_1 ALL NULL NULL NULL NULL 3
|
|
2 MATERIALIZED t_inner_2 ALL NULL NULL NULL NULL 9 Using join buffer (flat, BNL join)
|
|
3 MATERIALIZED t_inner_4 ALL NULL NULL NULL NULL 3
|
|
3 MATERIALIZED t_inner_3 ALL NULL NULL NULL NULL 9 Using join buffer (flat, BNL join)
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
explain select * from t1 t_outer_1,t2 t_outer_2 where t_outer_1.a in (select t_inner_1.a from t2 t_inner_2, t1 t_inner_1) and
|
|
t_outer_2.a in (select t_inner_3.a from t2 t_inner_3, t1 t_inner_4) {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#2 */ select t_inner_1.a from t2 t_inner_2 join t1 t_inner_1"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 3,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#3 */ select t_inner_3.a from t2 t_inner_3 join t1 t_inner_4"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#1 */ select t_outer_1.a AS a,t_outer_2.a AS a from t1 t_outer_1 join t2 t_outer_2 where t_outer_1.a in (/* select#2 */ select t_inner_1.a from t2 t_inner_2 join t1 t_inner_1) and t_outer_2.a in (/* select#3 */ select t_inner_3.a from t2 t_inner_3 join t1 t_inner_4)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"transformation": {
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"transformation": {
|
|
"select_id": 3,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"converted_to_semi_join": true
|
|
}
|
|
},
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "1 and 1 and t_outer_1.a = t_inner_1.a and t_outer_2.a = t_inner_3.a",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "1 and 1 and multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "1 and 1 and multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "multiple equal(t_outer_1.a, t_inner_1.a) and multiple equal(t_outer_2.a, t_inner_3.a)"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"row_may_be_null": false,
|
|
"map_bit": 2,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"row_may_be_null": false,
|
|
"map_bit": 3,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"row_may_be_null": false,
|
|
"map_bit": 4,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"row_may_be_null": false,
|
|
"map_bit": 5,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"table_scan": {
|
|
"rows": 9,
|
|
"cost": 2.015380859
|
|
}
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"table_scan": {
|
|
"rows": 3,
|
|
"cost": 2.005126953
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"semijoin_table_pullout": {
|
|
"pulled_out_tables": []
|
|
}
|
|
},
|
|
{
|
|
"execution_plan_for_potential_materialization": {
|
|
"steps": [
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_inner_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 10.02050781,
|
|
"estimated_join_cardinality": 27
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 3.815380859,
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_inner_4"],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 10.02050781,
|
|
"estimated_join_cardinality": 27
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 3.815380859,
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_outer_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 24.62563477,
|
|
"semijoin_strategy_choice": [
|
|
{
|
|
"strategy": "FirstMatch",
|
|
"records": 3,
|
|
"read_time": 44.75893555
|
|
},
|
|
{
|
|
"strategy": "SJ-Materialization",
|
|
"records": 3,
|
|
"read_time": 8.125634766
|
|
},
|
|
{
|
|
"strategy": "DuplicateWeedout",
|
|
"records": 3,
|
|
"read_time": 37.22563477
|
|
},
|
|
{
|
|
"chosen_strategy": "SJ-Materialization"
|
|
}
|
|
],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1", "t_inner_2"],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 15.54101562,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_outer_2"
|
|
],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 33.74614258,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_outer_2",
|
|
"t_inner_4"
|
|
],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 729,
|
|
"cost_for_plan": 181.5615234,
|
|
"semijoin_strategy_choice": [
|
|
{
|
|
"strategy": "FirstMatch",
|
|
"records": 27,
|
|
"read_time": 394.925293
|
|
},
|
|
{
|
|
"strategy": "SJ-Materialization",
|
|
"records": 27,
|
|
"read_time": 22.26152344
|
|
},
|
|
{
|
|
"strategy": "DuplicateWeedout",
|
|
"records": 27,
|
|
"read_time": 294.9615234
|
|
},
|
|
{
|
|
"chosen_strategy": "SJ-Materialization"
|
|
}
|
|
],
|
|
"estimated_join_cardinality": 27
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_outer_2"
|
|
],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 243,
|
|
"cost_for_plan": 66.15639648,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1", "t_inner_2"],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 11.93076172,
|
|
"semijoin_strategy_choice": [],
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_inner_4"
|
|
],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 30.14614258,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_cost": true
|
|
},
|
|
{
|
|
"plan_prefix": [
|
|
"t_outer_1",
|
|
"t_inner_1",
|
|
"t_inner_2",
|
|
"t_inner_4"
|
|
],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 30.14614258,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1", "t_inner_2"],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 15.54101562,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1"],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 24.62563477,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_cost": true
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1"],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 13.81538086,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1", "t_inner_1"],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 81,
|
|
"cost_for_plan": 24.62563477,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 10.02050781,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 10.02050781,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 6.410253906,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": ["t_outer_1"],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 27,
|
|
"cost_for_plan": 10.02050781,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_1",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 3.815380859,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_outer_2",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 3.815380859,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_4",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 3,
|
|
"cost": 2.005126953,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 3,
|
|
"cost": 2.005126953,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 3,
|
|
"cost_for_plan": 2.605126953,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t_inner_3",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 9,
|
|
"cost": 2.015380859,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 9,
|
|
"cost": 2.015380859,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 9,
|
|
"cost_for_plan": 3.815380859,
|
|
"semijoin_strategy_choice": [],
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"fix_semijoin_strategies_for_picked_join_order": [
|
|
{
|
|
"semi_join_strategy": "SJ-Materialization",
|
|
"join_order": [
|
|
{
|
|
"table": "t_inner_4"
|
|
},
|
|
{
|
|
"table": "t_inner_3"
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"semi_join_strategy": "SJ-Materialization",
|
|
"join_order": [
|
|
{
|
|
"table": "t_inner_1"
|
|
},
|
|
{
|
|
"table": "t_inner_2"
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": [
|
|
"t_outer_1",
|
|
"<subquery2>",
|
|
"t_outer_2",
|
|
"<subquery3>"
|
|
]
|
|
},
|
|
{
|
|
"condition_on_constant_tables": "1",
|
|
"computing_condition": []
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "1",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t_outer_1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_1",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_2",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "<subquery2>",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_outer_2",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_4",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "t_inner_3",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "<subquery3>",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
set @@optimizer_switch= @save_optimizer_switch;
|
|
drop table t1,t2;
|
|
#
|
|
# MDEV-18942: Json_writer::add_bool: Conditional jump or move depends on uninitialised value upon
|
|
# fulltext search under optimizer trace
|
|
#
|
|
CREATE TABLE t1 (f VARCHAR(255), FULLTEXT(f));
|
|
CREATE VIEW v1 AS SELECT * FROM t1;
|
|
INSERT INTO t1 VALUES ('fooba'),('abcde'),('xyzab');
|
|
SET optimizer_trace = 'enabled=on';
|
|
SELECT COUNT(*) FROM v1 WHERE MATCH (f) AGAINST ('fooba');
|
|
COUNT(*)
|
|
1
|
|
DROP VIEW v1;
|
|
DROP TABLE t1;
|
|
#
|
|
# MDEV-18741: Optimizer trace: multi-part key ranges are printed incorrectly.
|
|
#
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table one_k (a int);
|
|
insert into one_k select A.a + B.a*10 + C.a*100 from t0 A, t0 B, t0 C;
|
|
create table t1 ( a int, b int, key a_b(a,b));
|
|
insert into t1 select a,a from one_k;
|
|
set optimizer_trace='enabled=on';
|
|
explain select * from t1 force index (a_b) where a=2 and b=4;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref a_b a_b 10 const,const 1 Using index
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "a_b",
|
|
"ranges":
|
|
["(2,4) <= (a,b) <= (2,4)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 1,
|
|
"cost": 0.345829876,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
explain select * from t1 where a >= 900 and b between 10 and 20;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range a_b a_b 10 NULL 107 Using where; Using index
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "a_b",
|
|
"ranges":
|
|
["(900,10) <= (a,b)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 107,
|
|
"cost": 21.63379668,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t0,t1;
|
|
create table t1 (start_date date, end_date date, filler char(100), key(start_date, end_date)) ;
|
|
insert into t1 select date_add(now(), interval a day), date_add(now(), interval (a+7) day), 'data' from one_k;
|
|
explain select * from t1 force index(start_date) where start_date >= '2019-02-10' and end_date <'2019-04-01';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range start_date start_date 8 NULL 1000 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "start_date",
|
|
"ranges":
|
|
["(2019-02-10,NULL) < (start_date,end_date)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1000,
|
|
"cost": 1203.877243,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1,one_k;
|
|
create table ten(a int);
|
|
insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (
|
|
a int not null,
|
|
b int not null,
|
|
c int not null,
|
|
d int not null,
|
|
key a_b_c(a,b,c)
|
|
);
|
|
insert into t1 select a,a, a,a from ten;
|
|
explain select * from t1 force index(a_b_c) where a between 1 and 4 and b < 50;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 range a_b_c a_b_c 8 NULL 4 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "a_b_c",
|
|
"ranges":
|
|
["(1) <= (a,b) < (4,50)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 4,
|
|
"cost": 4.948710032,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table ten,t1;
|
|
# Ported test from MYSQL for ranges involving Binary column
|
|
CREATE TABLE t1(i INT PRIMARY KEY, b BINARY(16), INDEX i_b(b));
|
|
INSERT INTO t1 VALUES (1, x'D95B94336A9946A39CF5B58CFE772D8C');
|
|
INSERT INTO t1 VALUES (2, NULL);
|
|
EXPLAIN SELECT * FROM t1 WHERE b IN (0xD95B94336A9946A39CF5B58CFE772D8C);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 17 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(\xD9[\x943j\x99F\xA3\x9C\xF5\xB5\x8C\xFEw-\x8C) <= (b) <= (\xD9[\x943j\x99F\xA3\x9C\xF5\xB5\x8C\xFEw-\x8C)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.346171589,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
EXPLAIN SELECT * FROM t1 WHERE b IS NULL;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 17 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(NULL) <= (b) <= (NULL)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.346171589,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1;
|
|
#
|
|
# MDEV-18880: Optimizer trace prints date in hexadecimal
|
|
#
|
|
CREATE TABLE t1(i INT PRIMARY KEY, b VARCHAR(10) CHARSET BINARY , INDEX i_b(b));
|
|
INSERT INTO t1 VALUES (1, 'ab\n');
|
|
INSERT INTO t1 VALUES (2, NULL);
|
|
set optimizer_trace=1;
|
|
EXPLAIN SELECT * FROM t1 WHERE b='ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 13 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\x0A) <= (b) <= (ab\x0A)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345927508,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
ALTER TABLE t1 modify column b BINARY(10) AFTER i;
|
|
EXPLAIN SELECT * FROM t1 WHERE b='ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 11 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\x0A\x00\x00\x00\x00\x00\x00\x00) <= (b) <= (ab\x0A\x00\x00\x00\x00\x00\x00\x00)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345878692,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
ALTER TABLE t1 modify column b VARBINARY(10) AFTER i;
|
|
EXPLAIN SELECT * FROM t1 WHERE b='ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 13 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\x0A) <= (b) <= (ab\x0A)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345927508,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1;
|
|
CREATE TABLE t1(i INT PRIMARY KEY, b CHAR(10), INDEX i_b(b));
|
|
INSERT INTO t1 VALUES (1, 'ab\n');
|
|
INSERT INTO t1 VALUES (2, NULL);
|
|
EXPLAIN SELECT * FROM t1 WHERE b='ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 11 const 1 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\n) <= (b) <= (ab\n)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.345878692,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1;
|
|
CREATE TABLE t1(i INT PRIMARY KEY, b blob , INDEX i_b(b));
|
|
Warnings:
|
|
Note 1071 Specified key was too long; max key length is 1000 bytes
|
|
INSERT INTO t1 VALUES (1, 'ab\n');
|
|
INSERT INTO t1 VALUES (2, NULL);
|
|
set optimizer_trace=1;
|
|
EXPLAIN SELECT * FROM t1 WHERE b= 'ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 1003 const 1 Using where
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\x0A) <= (b) <= (ab\x0A)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.394255553,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1;
|
|
CREATE TABLE t1(i INT PRIMARY KEY, b VARCHAR(10), INDEX i_b(b));
|
|
INSERT INTO t1 VALUES (1, 'ab\n');
|
|
INSERT INTO t1 VALUES (2, 'ab\n');
|
|
set optimizer_trace=1;
|
|
EXPLAIN SELECT * FROM t1 WHERE b='ab\n';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref i_b i_b 13 const 2 Using index condition
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "i_b",
|
|
"ranges":
|
|
["(ab\n) <= (b) <= (ab\n)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 2,
|
|
"cost": 2.546855016,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1;
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table one_k (a int);
|
|
insert into one_k select A.a + B.a*10 + C.a*100 from t0 A, t0 B, t0 C;
|
|
create table t1 (start_date date, end_date date, filler char(100), key(start_date, end_date)) ;
|
|
insert into t1 select date_add(now(), interval a day), date_add(now(), interval (a+7) day), 'data' from one_k;
|
|
explain format=json select * from t1 force index(start_date) where start_date >= '2019-02-10' and end_date <'2019-04-01';
|
|
EXPLAIN
|
|
{
|
|
"query_block": {
|
|
"select_id": 1,
|
|
"table": {
|
|
"table_name": "t1",
|
|
"access_type": "range",
|
|
"possible_keys": ["start_date"],
|
|
"key": "start_date",
|
|
"key_length": "8",
|
|
"used_key_parts": ["start_date", "end_date"],
|
|
"rows": 1000,
|
|
"filtered": 100,
|
|
"index_condition": "t1.start_date >= '2019-02-10' and t1.end_date < '2019-04-01'"
|
|
}
|
|
}
|
|
}
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "start_date",
|
|
"ranges":
|
|
["(2019-02-10,NULL) < (start_date,end_date)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1000,
|
|
"cost": 1203.877243,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
drop table t1, t0, one_k;
|
|
#
|
|
# MDEV-19776: Assertion `to_len >= 8' failed in convert_to_printable with optimizer trace enabled
|
|
#
|
|
CREATE TABLE t1 (f VARBINARY(16) NOT NULL, KEY(f));
|
|
INSERT INTO t1 VALUES ('a'),('b');
|
|
SET optimizer_trace = 'enabled=on';
|
|
DELETE FROM t1 WHERE f = 'x';
|
|
DROP TABLE t1;
|
|
#
|
|
# Print cost_for_plan and rows_for_plan for join prefix
|
|
#
|
|
create table t0(a int);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table one_k (a int, b int, key(b));
|
|
insert into one_k select A.a + B.a*10 + C.a*100, A.a + B.a*10 + C.a*100 from t0 A, t0 B, t0 C;
|
|
analyze table t0, one_k persistent for all;
|
|
Table Op Msg_type Msg_text
|
|
test.t0 analyze status Engine-independent statistics collected
|
|
test.t0 analyze status OK
|
|
test.one_k analyze status Engine-independent statistics collected
|
|
test.one_k analyze status Table is already up to date
|
|
set @tmp_jcl=@@join_cache_level;
|
|
set join_cache_level=0;
|
|
set optimizer_trace=1;
|
|
# Check cost/row numbers when multiple tables are joined
|
|
# (cost_for_plan is the same as best_access_path.cost for single-table SELECTs
|
|
# but for joins using condition selectivity it is not as trivial. So,
|
|
# now we are printing it)
|
|
explain select * from t0 A, one_k B where A.a<5 and B.a<800;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE A ALL NULL NULL NULL NULL 10 Using where
|
|
1 SIMPLE B ALL NULL NULL NULL NULL 1000 Using where
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.considered_execution_plans')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "A",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 5.9375,
|
|
"cost": 2.829589844,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 5.9375,
|
|
"cost": 2.829589844,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 5.9375,
|
|
"cost_for_plan": 4.017089844,
|
|
"rest_of_plan":
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
["A"],
|
|
"table": "B",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 804.6875,
|
|
"cost": 256.8548584,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 804.6875,
|
|
"cost": 256.8548584,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 4777.832031,
|
|
"cost_for_plan": 1216.438354,
|
|
"estimated_join_cardinality": 4777.832031
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "B",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 804.6875,
|
|
"cost": 43.25976562,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 804.6875,
|
|
"cost": 43.25976562,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 804.6875,
|
|
"cost_for_plan": 204.1972656,
|
|
"pruned_by_heuristic": true
|
|
}
|
|
]
|
|
]
|
|
set join_cache_level=@tmp_jcl;
|
|
# This shows post-join selectivity
|
|
explain select * from t0 A, one_k B where A.a=B.b and B.a<800;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE A ALL NULL NULL NULL NULL 10 Using where
|
|
1 SIMPLE B ref b b 5 test.A.a 1 Using where
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.considered_execution_plans')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "A",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.017089844,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.017089844,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.017089844,
|
|
"rest_of_plan":
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
["A"],
|
|
"table": "B",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "ref",
|
|
"index": "b",
|
|
"used_range_estimates": false,
|
|
"cause": "not available",
|
|
"rows": 1,
|
|
"cost": 20.00585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 804.6875,
|
|
"cost": 43.25976562,
|
|
"chosen": false
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 20.00585794,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 26.02294779,
|
|
"selectivity": 0.8046875,
|
|
"estimated_join_cardinality": 8.046875
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "B",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 804.6875,
|
|
"cost": 43.25976562,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 804.6875,
|
|
"cost": 43.25976562,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 804.6875,
|
|
"cost_for_plan": 204.1972656,
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
]
|
|
drop table t0, one_k;
|
|
#
|
|
# Assertion `to_len >= 8' failed in convert_to_printable
|
|
#
|
|
CREATE TABLE t1 ( a blob, KEY (a(255)));
|
|
insert into t1 values ('foo'), ('bar');
|
|
EXPLAIN SELECT * FROM t1 WHERE a= REPEAT('a', 0);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ref a a 258 const 1 Using where
|
|
SELECT * FROM t1 WHERE a= REPEAT('a', 0);
|
|
a
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.analyzing_range_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
{
|
|
"range_scan_alternatives":
|
|
[
|
|
{
|
|
"index": "a",
|
|
"ranges":
|
|
["() <= (a) <= ()"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 1,
|
|
"cost": 1.357887479,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"analyzing_roworder_intersect":
|
|
{
|
|
"cause": "too few roworder scans"
|
|
},
|
|
"analyzing_index_merge_union":
|
|
[]
|
|
}
|
|
]
|
|
DROP TABLE t1;
|
|
#
|
|
# Test for Semi-Join table pullout element
|
|
#
|
|
create table t1 (a int primary key, b int);
|
|
insert into t1 (a) values (1),(2),(3),(4),(5);
|
|
create table t2 (a int primary key, b int);
|
|
insert into t2 (a) values (1),(2),(3),(4),(5);
|
|
create table t3 (a int);
|
|
insert into t3 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
explain
|
|
select * from t3 where (a,a) in (select t1.a, t2.a from t1, t2 where t1.b=t2.b);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL PRIMARY NULL NULL NULL 5
|
|
1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 Using where
|
|
1 PRIMARY t3 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.semijoin_table_pullout')) from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JSON_DETAILED(JSON_EXTRACT(trace, '$**.semijoin_table_pullout'))
|
|
[
|
|
{
|
|
"pulled_out_tables":
|
|
[
|
|
"t2",
|
|
"t1"
|
|
]
|
|
}
|
|
]
|
|
drop table t1,t2,t3;
|
|
#
|
|
# MDEV-22401: Optimizer trace: multi-component range is not printed correctly
|
|
#
|
|
create table t1 (kp1 int, kp2 int, key(kp1, kp2));
|
|
insert into t1 values (1,1),(1,5),(5,1),(5,5);
|
|
set optimizer_trace=1;
|
|
select * from t1 force index(kp1) where (kp1=2 and kp2 >=4);
|
|
kp1 kp2
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.range_scan_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"index": "kp1",
|
|
"ranges":
|
|
["(2,4) <= (kp1,kp2) <= (2)"],
|
|
"rowid_ordered": false,
|
|
"using_mrr": false,
|
|
"index_only": true,
|
|
"rows": 1,
|
|
"cost": 0.345829876,
|
|
"chosen": true
|
|
}
|
|
]
|
|
]
|
|
drop table t1;
|
|
#
|
|
# MDEV-21626: Optimizer misses the details about the picked join order
|
|
#
|
|
CREATE TABLE t1(a INT, b INT, key(a));
|
|
INSERT INTO t1 SELECT seq, seq from seq_1_to_10;
|
|
CREATE TABLE t2(a INT, b INT, key(a));
|
|
INSERT INTO t2 SELECT seq, seq from seq_1_to_100;
|
|
SET OPTIMIZER_TRACE=1;
|
|
EXPLAIN SELECT * FROM t1, t2 WHERE t1.a=t2.a ORDER BY t2.b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 ALL a NULL NULL NULL 10 Using where; Using temporary; Using filesort
|
|
1 SIMPLE t2 ref a a 5 test.t1.a 1
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.considered_execution_plans')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "t1",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 4.021972656,
|
|
"rest_of_plan":
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
["t1"],
|
|
"table": "t2",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not available",
|
|
"rows": 1,
|
|
"cost": 20.00585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.219726562,
|
|
"chosen": false
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "ref",
|
|
"records": 1,
|
|
"cost": 20.00585794,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10,
|
|
"cost_for_plan": 26.0278306,
|
|
"cost_for_sorting": 10,
|
|
"estimated_join_cardinality": 10
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix":
|
|
[],
|
|
"table": "t2",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 100,
|
|
"cost": 2.219726562,
|
|
"chosen": true,
|
|
"use_tmp_table": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 100,
|
|
"cost": 2.219726562,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 100,
|
|
"cost_for_plan": 22.21972656,
|
|
"rest_of_plan":
|
|
[
|
|
{
|
|
"plan_prefix":
|
|
["t2"],
|
|
"table": "t1",
|
|
"best_access_path":
|
|
{
|
|
"considered_access_paths":
|
|
[
|
|
{
|
|
"access_type": "ref",
|
|
"index": "a",
|
|
"used_range_estimates": false,
|
|
"cause": "not available",
|
|
"rows": 1,
|
|
"cost": 200.0585794,
|
|
"chosen": true
|
|
},
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10,
|
|
"cost": 2.021972656,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method":
|
|
{
|
|
"type": "scan",
|
|
"records": 10,
|
|
"cost": 2.021972656,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 1000,
|
|
"cost_for_plan": 224.2416992,
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
]
|
|
DROP TABLE t1,t2;
|
|
#
|
|
# MDEV-22665: Print ranges in the optimizer trace created for non-indexed columns when
|
|
# optimizer_use_condition_selectivity >2
|
|
#
|
|
CREATE TABLE t1(a INT, b INT);
|
|
INSERT INTO t1 SELECT seq, seq from seq_1_to_100;
|
|
SET optimizer_trace=1;
|
|
ANALYZE TABLE t1 PERSISTENT FOR ALL;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
EXPLAIN EXTENDED SELECT * from t1 WHERE a between 1 and 5 and b <= 5;
|
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 0.22 Using where
|
|
Warnings:
|
|
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where `test`.`t1`.`a` between 1 and 5 and `test`.`t1`.`b` <= 5
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.selectivity_for_columns')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"column_name": "a",
|
|
"ranges":
|
|
["1 <= a <= 5"],
|
|
"selectivity_from_histogram": 0.046875
|
|
},
|
|
{
|
|
"column_name": "b",
|
|
"ranges":
|
|
["NULL < b <= 5"],
|
|
"selectivity_from_histogram": 0.046875
|
|
}
|
|
]
|
|
]
|
|
EXPLAIN EXTENDED SELECT * from t1 WHERE a != 5;
|
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 100.00 Using where
|
|
Warnings:
|
|
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where `test`.`t1`.`a` <> 5
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.selectivity_for_columns')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"column_name": "a",
|
|
"ranges":
|
|
[
|
|
"NULL < a < 5",
|
|
"5 < a"
|
|
],
|
|
"selectivity_from_histogram": 1
|
|
}
|
|
]
|
|
]
|
|
EXPLAIN EXTENDED SELECT * from t1 WHERE b >= 10 and b < 25;
|
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 15.62 Using where
|
|
Warnings:
|
|
Note 1003 select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where `test`.`t1`.`b` >= 10 and `test`.`t1`.`b` < 25
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.selectivity_for_columns')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"column_name": "b",
|
|
"ranges":
|
|
["10 <= b < 25"],
|
|
"selectivity_from_histogram": 0.15625
|
|
}
|
|
]
|
|
]
|
|
drop table t1;
|
|
#
|
|
# MDEV-22910:SIGSEGV in Opt_trace_context::is_started & SIGSEGV in Json_writer::add_table_name
|
|
# (on optimized builds)
|
|
#
|
|
CREATE TABLE t1( a INT, b INT, PRIMARY KEY( a ) );
|
|
SELECT sum(b), row_number() OVER (order by b) FROM t1 WHERE a = 101;
|
|
sum(b) row_number() OVER (order by b)
|
|
NULL 1
|
|
UPDATE t1 SET b=10 WHERE a=1;
|
|
SELECT JSON_DETAILED(JSON_EXTRACT(trace, '$**.range_scan_alternatives')) AS JS from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
JS
|
|
[
|
|
[
|
|
{
|
|
"index": "PRIMARY",
|
|
"ranges":
|
|
["(1) <= (a) <= (1)"],
|
|
"rowid_ordered": true,
|
|
"using_mrr": false,
|
|
"index_only": false,
|
|
"rows": 0,
|
|
"cost": 0.145,
|
|
"chosen": true
|
|
}
|
|
]
|
|
]
|
|
DROP TABLE t1;
|
|
set optimizer_trace='enabled=off';
|
|
#
|
|
# MDEV-24975 Server consumes extra 4G memory upon querying INFORMATION_SCHEMA.OPTIIMIZER_TRACE
|
|
#
|
|
set max_session_mem_used=1024*1024*1024;
|
|
select count(*) from information_schema.optimizer_trace;
|
|
select * from information_schema.optimizer_trace;
|
|
set max_session_mem_used=default;
|
|
#
|
|
# MDEV-22380 Assertion `name.length == strlen(name.str)' failed in Item::print_item_w_name on SELECT w/ optimizer_trace enabled
|
|
#
|
|
SET optimizer_trace="enabled=on";
|
|
SELECT 'a\0' LIMIT 0;
|
|
a\x00
|
|
SELECT query, trace FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
query trace
|
|
SELECT 'a\0' LIMIT 0 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select 'a\0' AS `a\x00` limit 0"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
}
|
|
SET optimizer_trace=DEFAULT;
|
|
#
|
|
# MDEV-27238: Assertion `got_name == named_item_expected()' failed in Json_writer::on_start_object
|
|
#
|
|
CREATE TABLE t1 (a INT KEY,b INT,KEY(b)) ENGINE=MEMORY;
|
|
SET optimizer_trace=1;
|
|
INSERT INTO t1 VALUES (0,0);
|
|
SELECT a FROM t1 WHERE (a,b) in (SELECT @c,@d);
|
|
a
|
|
DROP TABLE t1;
|
|
#
|
|
# MDEV-30964: MAX_SEL_ARG memory exhaustion is not visible in the optimizer trace
|
|
#
|
|
create table t1 (
|
|
c1 int,
|
|
c2 int,
|
|
c3 int,
|
|
c4 int,
|
|
c5 int,
|
|
c6 int,
|
|
c7 int,
|
|
c8 int,
|
|
key(c1,c2,c3,c4,c5,c6,c7,c8)
|
|
);
|
|
insert into t1 () values (),(),();
|
|
explain select *
|
|
from t1
|
|
where
|
|
(c1 in (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16) and c2=1) and
|
|
c3 in (1,2,3,4,5,6,7,8,9,10) and
|
|
c4 in (1,2,3,4,5,6,7,8,9,10) and
|
|
c5 in (1,2,3,4,5,6,7,8,9,10) and
|
|
c6 in (1,2,3,4);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t1 index c1 c1 40 NULL 3 Using where; Using index
|
|
select
|
|
json_detailed(json_extract(trace, '$**.setup_range_conditions'))
|
|
from
|
|
information_schema.optimizer_trace;
|
|
json_detailed(json_extract(trace, '$**.setup_range_conditions'))
|
|
[
|
|
[
|
|
{
|
|
"enforce_sel_arg_weight_limit":
|
|
{
|
|
"index": "c1",
|
|
"old_weight": 74806,
|
|
"new_weight": 1776
|
|
}
|
|
},
|
|
{
|
|
"sel_arg_alloc_limit_hit":
|
|
{
|
|
"alloced_sel_args": 16001
|
|
}
|
|
}
|
|
]
|
|
]
|
|
drop table t1;
|
|
#
|
|
# MDEV-31085: multi-update using view with optimizer trace enabled
|
|
#
|
|
SET SESSION optimizer_trace = 'enabled=on';
|
|
CREATE TABLE t (a int, b int);
|
|
CREATE VIEW v AS SELECT 1 AS c UNION SELECT 2 AS c;
|
|
INSERT INTO t VALUES (0,4),(5,6);
|
|
UPDATE t, v SET t.b = t.a, t.a = v.c WHERE v.c < t.a;
|
|
SELECT * FROM information_schema.optimizer_trace;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
UPDATE t, v SET t.b = t.a, t.a = v.c WHERE v.c < t.a {
|
|
"steps": [
|
|
{
|
|
"view": {
|
|
"table": "v",
|
|
"select_id": 2,
|
|
"algorithm": "materialized"
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 2,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#2 */ select 1 AS c"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 3,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#3 */ select 2 AS c"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "/* select#1 */ update t join v set t.b = t.a,t.a = v.c where v.c < t.a"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"condition_processing": {
|
|
"condition": "WHERE",
|
|
"original_condition": "v.c < t.a",
|
|
"steps": [
|
|
{
|
|
"transformation": "equality_propagation",
|
|
"resulting_condition": "v.c < t.a"
|
|
},
|
|
{
|
|
"transformation": "constant_propagation",
|
|
"resulting_condition": "v.c < t.a"
|
|
},
|
|
{
|
|
"transformation": "trivial_condition_removal",
|
|
"resulting_condition": "v.c < t.a"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 2,
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 3,
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "t",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
},
|
|
{
|
|
"table": "<derived2>",
|
|
"row_may_be_null": false,
|
|
"map_bit": 1,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"ref_optimizer_key_uses": []
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "t",
|
|
"table_scan": {
|
|
"rows": 2,
|
|
"cost": 2.004394531
|
|
}
|
|
},
|
|
{
|
|
"table": "<derived2>",
|
|
"table_scan": {
|
|
"rows": 2,
|
|
"cost": 2
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "t",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 2.004394531,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 2.004394531,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 2,
|
|
"cost_for_plan": 2.404394531,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["t"],
|
|
"table": "<derived2>",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 2,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 2,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 5.204394531,
|
|
"estimated_join_cardinality": 4
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "<derived2>",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 2,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 2,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 2,
|
|
"cost_for_plan": 2.4,
|
|
"rest_of_plan": [
|
|
{
|
|
"plan_prefix": ["<derived2>"],
|
|
"table": "t",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 2.004394531,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 2.004394531,
|
|
"uses_join_buffering": true
|
|
}
|
|
},
|
|
"rows_for_plan": 4,
|
|
"cost_for_plan": 5.204394531,
|
|
"pruned_by_cost": true
|
|
}
|
|
]
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["t", "<derived2>"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": "v.c < t.a",
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "t",
|
|
"attached": null
|
|
},
|
|
{
|
|
"table": "<derived2>",
|
|
"attached": "v.c < t.a"
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"join_execution": {
|
|
"select_id": 2,
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 3,
|
|
"steps": []
|
|
}
|
|
},
|
|
{
|
|
"join_preparation": {
|
|
"select_id": "fake",
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select c AS c from dual"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": "fake",
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "union",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "union",
|
|
"table_scan": {
|
|
"rows": 2,
|
|
"cost": 10.1
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "union",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 2,
|
|
"cost": 10.1,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 2,
|
|
"cost": 10.1,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 2,
|
|
"cost_for_plan": 10.5,
|
|
"estimated_join_cardinality": 2
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["union"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "union",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": "fake",
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
SELECT * FROM t;
|
|
a b
|
|
0 4
|
|
1 5
|
|
SET optimizer_trace=DEFAULT;
|
|
DROP VIEW v;
|
|
DROP TABLE t;
|
|
#
|
|
# MDEV-26301: Split optimization improvements: Optimizer Trace coverage
|
|
#
|
|
create table t1(a int, b int);
|
|
insert into t1 select seq,seq from seq_1_to_5;
|
|
create table t2(a int, b int, key(a));
|
|
insert into t2
|
|
select A.seq,B.seq from seq_1_to_25 A, seq_1_to_2 B;
|
|
create table t3(a int, b int, key(a));
|
|
insert into t3
|
|
select A.seq,B.seq from seq_1_to_5 A, seq_1_to_3 B;
|
|
analyze table t1,t2,t3 persistent for all;
|
|
Table Op Msg_type Msg_text
|
|
test.t1 analyze status Engine-independent statistics collected
|
|
test.t1 analyze status OK
|
|
test.t2 analyze status Engine-independent statistics collected
|
|
test.t2 analyze status Table is already up to date
|
|
test.t3 analyze status Engine-independent statistics collected
|
|
test.t3 analyze status Table is already up to date
|
|
create table t10 (
|
|
grp_id int,
|
|
col1 int,
|
|
key(grp_id)
|
|
);
|
|
insert into t10
|
|
select
|
|
A.seq,
|
|
B.seq
|
|
from
|
|
seq_1_to_100 A,
|
|
seq_1_to_100 B;
|
|
create table t11 (
|
|
col1 int,
|
|
col2 int
|
|
);
|
|
insert into t11
|
|
select A.seq, A.seq from seq_1_to_10 A;
|
|
analyze table t10,t11 persistent for all;
|
|
Table Op Msg_type Msg_text
|
|
test.t10 analyze status Engine-independent statistics collected
|
|
test.t10 analyze status Table is already up to date
|
|
test.t11 analyze status Engine-independent statistics collected
|
|
test.t11 analyze status OK
|
|
set optimizer_trace=1;
|
|
explain
|
|
select * from
|
|
(
|
|
(t1 left join t2 on t2.a=t1.b)
|
|
left join t3 on t3.a=t1.b
|
|
) left join (select grp_id, count(*)
|
|
from t10 left join t11 on t11.col1=t10.col1
|
|
group by grp_id) T on T.grp_id=t1.b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 5
|
|
1 PRIMARY t2 ref a a 5 test.t1.b 2 Using where
|
|
1 PRIMARY t3 ref a a 5 test.t1.b 3 Using where
|
|
1 PRIMARY <derived2> ref key0 key0 5 test.t1.b 10 Using where
|
|
2 LATERAL DERIVED t10 ref grp_id grp_id 5 test.t1.b 100
|
|
2 LATERAL DERIVED t11 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
|
|
select json_detailed(json_extract(trace, '$**.check_split_materialized')) as JS
|
|
from information_schema.optimizer_trace;
|
|
JS
|
|
[
|
|
{
|
|
"split_candidates":
|
|
["t10.grp_id"]
|
|
}
|
|
]
|
|
select
|
|
json_detailed(
|
|
json_remove(
|
|
json_extract(trace, '$**.choose_best_splitting')
|
|
, '$[0].split_plan_search[0]'
|
|
)
|
|
) as JS
|
|
from information_schema.optimizer_trace;
|
|
JS
|
|
[
|
|
{
|
|
"considered_keys":
|
|
[
|
|
{
|
|
"table_name": "t10",
|
|
"index": "grp_id",
|
|
"rec_per_key": 100,
|
|
"param_tables": 1
|
|
}
|
|
],
|
|
"refills": 5,
|
|
"spl_pd_boundary": 2,
|
|
"split_plan_search":
|
|
[],
|
|
"lead_table": "t10",
|
|
"index": "grp_id",
|
|
"parts": 1,
|
|
"split_sel": 0.001,
|
|
"cost": 2535.968504,
|
|
"records": 100,
|
|
"refills": 5,
|
|
"chosen": true
|
|
}
|
|
]
|
|
drop table t1,t2,t3,t10,t11;
|
|
set optimizer_trace=DEFAULT;
|
|
#
|
|
# MDEV-29179 Condition pushdown from HAVING into WHERE is not shown in optimizer trace
|
|
#
|
|
CREATE TABLE t1 (a INT, b VARCHAR(1), KEY (a), KEY(b,a)) ENGINE=MEMORY;
|
|
INSERT INTO t1 VALUES (4,'n'),(1,'h'),(NULL,'w');
|
|
SET optimizer_trace= 'enabled=on';
|
|
SELECT b, a FROM t1 WHERE b <> 'p' OR a = 4 GROUP BY b, a HAVING a <= 7;
|
|
b a
|
|
h 1
|
|
n 4
|
|
SELECT json_detailed(json_extract(trace, '$**.steps[*].join_optimization.steps[*].condition_pushdown_from_having') ) exp1, JSON_VALID(trace) exp2 FROM information_schema.optimizer_trace;
|
|
exp1 exp2
|
|
[
|
|
{
|
|
"conds": "(t1.b <> 'p' or multiple equal(4, t1.a)) and t1.a <= 7",
|
|
"having": null
|
|
}
|
|
] 1
|
|
DROP TABLE t1;
|
|
#
|
|
# End of 10.4 tests
|
|
#
|
|
set optimizer_trace='enabled=on';
|
|
#
|
|
# Test many rows to see output of big cost numbers
|
|
#
|
|
select count(*) from seq_1_to_10000000;
|
|
count(*)
|
|
10000000
|
|
select * from INFORMATION_SCHEMA.OPTIMIZER_TRACE;
|
|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
|
|
select count(*) from seq_1_to_10000000 {
|
|
"steps": [
|
|
{
|
|
"join_preparation": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"expanded_query": "select count(0) AS `count(*)` from seq_1_to_10000000"
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_optimization": {
|
|
"select_id": 1,
|
|
"steps": [
|
|
{
|
|
"table_dependencies": [
|
|
{
|
|
"table": "seq_1_to_10000000",
|
|
"row_may_be_null": false,
|
|
"map_bit": 0,
|
|
"depends_on_map_bits": []
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"rows_estimation": [
|
|
{
|
|
"table": "seq_1_to_10000000",
|
|
"table_scan": {
|
|
"rows": 10000000,
|
|
"cost": 10000000
|
|
}
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"considered_execution_plans": [
|
|
{
|
|
"plan_prefix": [],
|
|
"table": "seq_1_to_10000000",
|
|
"best_access_path": {
|
|
"considered_access_paths": [
|
|
{
|
|
"access_type": "scan",
|
|
"resulting_rows": 10000000,
|
|
"cost": 10000000,
|
|
"chosen": true
|
|
}
|
|
],
|
|
"chosen_access_method": {
|
|
"type": "scan",
|
|
"records": 10000000,
|
|
"cost": 10000000,
|
|
"uses_join_buffering": false
|
|
}
|
|
},
|
|
"rows_for_plan": 10000000,
|
|
"cost_for_plan": 12000000,
|
|
"estimated_join_cardinality": 10000000
|
|
}
|
|
]
|
|
},
|
|
{
|
|
"best_join_order": ["seq_1_to_10000000"]
|
|
},
|
|
{
|
|
"attaching_conditions_to_tables": {
|
|
"original_condition": null,
|
|
"attached_conditions_computation": [],
|
|
"attached_conditions_summary": [
|
|
{
|
|
"table": "seq_1_to_10000000",
|
|
"attached": null
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
},
|
|
{
|
|
"join_execution": {
|
|
"select_id": 1,
|
|
"steps": []
|
|
}
|
|
}
|
|
]
|
|
} 0 0
|
|
#
|
|
# MDEV-22891: Optimizer trace: const tables are not clearly visible
|
|
#
|
|
create table t0(a int primary key);
|
|
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
create table t1 (pk int primary key, a int);
|
|
insert into t1 select a,a from t0;
|
|
create table t2 (pk int primary key, a int);
|
|
insert into t2 select a,a from t0;
|
|
create table t3 (pk int primary key, a int);
|
|
insert into t3 select a,a from t0;
|
|
explain
|
|
select * from t1 left join (t2 join t3 on t3.pk=1000) on t2.a=t1.a and t2.pk is null;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t3 const PRIMARY NULL NULL NULL 1 Impossible ON condition
|
|
1 SIMPLE t2 const PRIMARY NULL NULL NULL 1 Impossible ON condition
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 10
|
|
select JSON_DETAILED(JSON_EXTRACT(trace, '$**.mark_join_nest_as_const')) as jd
|
|
from information_schema.optimizer_trace;
|
|
jd
|
|
[
|
|
{
|
|
"members":
|
|
[
|
|
"t3",
|
|
"t2"
|
|
]
|
|
}
|
|
]
|
|
drop table t0, t1, t2, t3;
|
|
#
|
|
# MDEV-23767: IN-to-subquery conversion is not visible in optimizer trace
|
|
#
|
|
create table t0 (a int);
|
|
INSERT INTO t0 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
|
|
set @tmp=@@in_predicate_conversion_threshold;
|
|
set in_predicate_conversion_threshold=3;
|
|
explain select * from t0 where a in (1,2,3,4,5,6);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t0 ALL NULL NULL NULL NULL 10 Using where
|
|
1 PRIMARY <derived3> ref key0 key0 4 test.t0.a 2 FirstMatch(t0)
|
|
3 DERIVED NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
select json_detailed(json_extract(trace, '$**.in_to_subquery_conversion')) as jd
|
|
from information_schema.optimizer_trace;
|
|
jd
|
|
[
|
|
{
|
|
"item": "t0.a in (1,2,3,4,5,6)",
|
|
"conversion":
|
|
[
|
|
{
|
|
"join_preparation":
|
|
{
|
|
"select_id": 2,
|
|
"steps":
|
|
[
|
|
{
|
|
"derived":
|
|
{
|
|
"table": "tvc_0",
|
|
"select_id": 3,
|
|
"algorithm": "materialized"
|
|
}
|
|
},
|
|
{
|
|
"transformation":
|
|
{
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "materialization",
|
|
"sjm_scan_allowed": true,
|
|
"possible": true
|
|
}
|
|
},
|
|
{
|
|
"transformation":
|
|
{
|
|
"select_id": 2,
|
|
"from": "IN (SELECT)",
|
|
"to": "semijoin",
|
|
"chosen": true
|
|
}
|
|
},
|
|
{
|
|
"expanded_query": "/* select#2 */ select tvc_0._col_1 from (values (1),(2),(3),(4),(5),(6)) tvc_0"
|
|
}
|
|
]
|
|
}
|
|
}
|
|
]
|
|
}
|
|
]
|
|
explain select * from t0 where a in (1,2,3,4,5,a+1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
|
|
select json_detailed(json_extract(trace, '$**.in_to_subquery_conversion')) as jd
|
|
from information_schema.optimizer_trace;
|
|
jd
|
|
[
|
|
{
|
|
"item": "t0.a in (1,2,3,4,5,t0.a + 1)",
|
|
"done": false,
|
|
"reason": "non-constant element in the IN-list"
|
|
}
|
|
]
|
|
explain select * from t0 where a in ('1','2','3','4','5','6');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
|
|
select json_detailed(json_extract(trace, '$**.in_to_subquery_conversion')) as jd
|
|
from information_schema.optimizer_trace;
|
|
jd
|
|
[
|
|
{
|
|
"item": "t0.a in ('1','2','3','4','5','6')",
|
|
"done": false,
|
|
"reason": "type mismatch"
|
|
}
|
|
]
|
|
set in_predicate_conversion_threshold=@tmp;
|
|
drop table t0;
|
|
#
|
|
# MDEV-29298: INSERT ... SELECT Does not produce an optimizer trace
|
|
#
|
|
create table t1 (a int, b int);
|
|
create table t2 (a int, b int);
|
|
insert into t1 values (1,1), (2,2), (3,3), (4,4), (5,5);
|
|
set optimizer_trace=1;
|
|
insert into t2 select * from t1 where a<= b and a>4;
|
|
select QUERY, LENGTH(trace)>1 from information_schema.optimizer_trace;
|
|
QUERY LENGTH(trace)>1
|
|
insert into t2 select * from t1 where a<= b and a>4 1
|
|
drop table t1, t2;
|
|
#
|
|
# MDEV-34305 Redundant truncation errors/warnings with optimizer_trace enabled
|
|
#
|
|
SET @@optimizer_trace='enabled=on';
|
|
CREATE TABLE t1 (
|
|
a CHAR(2) NOT NULL PRIMARY KEY,
|
|
b VARCHAR(20) NOT NULL,
|
|
KEY (b)
|
|
) CHARSET=utf8mb4;
|
|
CREATE TABLE t2 (
|
|
a CHAR(2) NOT NULL PRIMARY KEY,
|
|
b VARCHAR(20) NOT NULL,
|
|
KEY (b)
|
|
) CHARSET=utf8mb4;
|
|
INSERT INTO t1 VALUES
|
|
('AB','MySQLAB'),
|
|
('JA','Sun Microsystems'),
|
|
('MS','Microsoft'),
|
|
('IB','IBM- Inc.'),
|
|
('GO','Google Inc.');
|
|
INSERT IGNORE INTO t2 VALUES
|
|
('AB','Sweden'),
|
|
('JA','USA'),
|
|
('MS','United States'),
|
|
('IB','North America'),
|
|
('GO','South America');
|
|
UPDATE t1,t2 SET t1.b=UPPER(t1.b) WHERE t1.b LIKE 'Unknown%';
|
|
DROP TABLE t1, t2;
|
|
# End of 10.5 tests
|
|
set optimizer_trace='enabled=off';
|