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polardbxengine/mysql-test/suite/opt_trace/r/general_no_prot_all.result

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set optimizer_switch='semijoin=on,materialization=on,firstmatch=on,loosescan=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=off';
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
set optimizer_trace_max_mem_size=1048576;
set @@session.optimizer_trace="enabled=on";
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
CREATE TABLE t5 (c int);
INSERT INTO t5 VALUES (NULL);
CREATE TABLE t6 (d int , KEY (d));
INSERT INTO t6 VALUES (NULL),(NULL);
SELECT (SELECT 1 FROM t6 WHERE d = c) AS RESULT FROM t5 ;
RESULT
NULL
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT (SELECT 1 FROM t6 WHERE d = c) AS RESULT FROM t5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = `t5`.`c`)"
}
]
}
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select 1 from `t6` where (`t6`.`d` = `t5`.`c`)) AS `RESULT` from `t5`"
}
]
}
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
]
}
]
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
]
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
],
"attached_conditions_summary": [
]
}
},
{
"refine_plan": [
]
}
]
}
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = NULL)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal(NULL, `t6`.`d`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal(NULL, `t6`.`d`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal(NULL, `t6`.`d`)"
}
]
}
},
{
"substitute_generated_columns": {
}
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
]
}
]
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "NULL",
"null_rejecting": true
}
]
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
},
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
]
}
],
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
},
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
}
}
],
"impossible_range": true
},
"rows": 0,
"cause": "impossible_where_condition"
}
]
}
],
"empty_result": {
"cause": "no matching row in const table"
}
}
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"select#": 2,
"steps": [
]
}
}
]
}
}
]
}
}
]
} 0 0
select (1-length(replace(TRACE, " ", ""))/length(TRACE))*100
from information_schema.OPTIMIZER_TRACE;
(1-length(replace(TRACE, " ", ""))/length(TRACE))*100
53.9648
set optimizer_trace="one_line=on";
SELECT (SELECT 1 FROM t6 WHERE d = c) AS RESULT FROM t5 ;
RESULT
NULL
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT (SELECT 1 FROM t6 WHERE d = c) AS RESULT FROM t5 {"steps": [{"join_preparation": {"select#": 1,"steps": [{"join_preparation": {"select#": 2,"steps": [{"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = `t5`.`c`)"}]}},{"expanded_query": "/* select#1 */ select (/* select#2 */ select 1 from `t6` where (`t6`.`d` = `t5`.`c`)) AS `RESULT` from `t5`"}]}},{"join_optimization": {"select#": 1,"steps": [{"table_dependencies": [{"table": "`t5`","row_may_be_null": false,"map_bit": 0,"depends_on_map_bits": []}]},{"rows_estimation": [{"table": "`t5`","rows": 1,"cost": 1,"table_type": "system","empty": false}]},{"attaching_conditions_to_tables": {"original_condition": null,"attached_conditions_computation": [],"attached_conditions_summary": []}},{"refine_plan": []}]}},{"join_optimization": {"select#": 2,"steps": [{"condition_processing": {"condition": "WHERE","original_condition": "(`t6`.`d` = NULL)","steps": [{"transformation": "equality_propagation","resulting_condition": "multiple equal(NULL, `t6`.`d`)"},{"transformation": "constant_propagation","resulting_condition": "multiple equal(NULL, `t6`.`d`)"},{"transformation": "trivial_condition_removal","resulting_condition": "multiple equal(NULL, `t6`.`d`)"}]}},{"substitute_generated_columns": {}},{"table_dependencies": [{"table": "`t6`","row_may_be_null": false,"map_bit": 0,"depends_on_map_bits": []}]},{"ref_optimizer_key_uses": [{"table": "`t6`","field": "d","equals": "NULL","null_rejecting": true}]},{"rows_estimation": [{"table": "`t6`","range_analysis": {"table_scan": {"rows": 2,"cost": 2.8009},"potential_range_indexes": [{"index": "d","usable": true,"key_parts": ["d"]}],"best_covering_index_scan": {"index": "d","cost": 0.4558,"chosen": true},"setup_range_conditions": [{"impossible_condition": {"cause": "comparison_with_null_always_false"}}],"impossible_range": true},"rows": 0,"cause": "impossible_where_condition"}]}],"empty_result": {"cause": "no matching row in const table"}}},{"join_execution": {"select#": 1,"steps": [{"subselect_execution": {"select#": 2,"steps": [{"join_execution": {"select#": 2,"steps": []}}]}}]}}]} 0 0
select (1-length(replace(TRACE, " ", ""))/length(TRACE))*100
from information_schema.OPTIMIZER_TRACE;
(1-length(replace(TRACE, " ", ""))/length(TRACE))*100
6.0048
set end_markers_in_json=on;
set optimizer_trace="one_line=off";
EXPLAIN SELECT (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 ;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t5 NULL system NULL NULL NULL NULL 1 100.00 NULL
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL NULL no matching row in const table
Warnings:
Note 1276 Field or reference 'test.t5.c' of SELECT #2 was resolved in SELECT #1
Note 1003 /* select#1 */ select (/* select#2 */ select 1 from `test`.`t6` where (`test`.`t6`.`d` = ifnull(NULL,NULL))) AS `RESULT` from dual
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
EXPLAIN SELECT (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))) AS `RESULT` from `t5`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = ifnull(NULL,NULL))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "ifnull(NULL,NULL)",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
} /* impossible_condition */
}
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
}
] /* rows_estimation */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
SELECT /* should be last */ (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 ;
RESULT
NULL
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT /* should be last */ (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))) AS `RESULT` from `t5`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = ifnull(NULL,NULL))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "ifnull(NULL,NULL)",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
} /* impossible_condition */
}
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
}
] /* rows_estimation */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set @@session.optimizer_trace="enabled=off";
SELECT /* bug if you see this*/ (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 ;
RESULT
NULL
select QUERY from information_schema.OPTIMIZER_TRACE;
QUERY
SELECT /* should be last */ (SELECT 1 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5
set @@session.optimizer_trace="enabled=on";
SELECT (SELECT 1 FROM t6 WHERE d = ifnull(c,null) UNION SELECT 2 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 ;
RESULT
NULL
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT (SELECT 1 FROM t6 WHERE d = ifnull(c,null) UNION SELECT 2 FROM t6 WHERE d = ifnull(c,null)) AS RESULT FROM t5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select 2 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
}
] /* steps */
} /* join_preparation */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"columns": 1,
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` from dual"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL)) union /* select#3 */ select 2 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))) AS `RESULT` from `t5`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = ifnull(NULL,NULL))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "ifnull(NULL,NULL)",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
} /* impossible_condition */
}
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
}
] /* rows_estimation */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 3,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = ifnull(NULL,NULL))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` = ifnull(NULL,NULL))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "ifnull(NULL,NULL)",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
} /* impossible_condition */
}
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
}
] /* rows_estimation */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_optimization": {
"select#": "fake",
"steps": [
{
"table_dependencies": [
{
"table": "``.``",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "``.``",
"table_scan": {
"rows": 0,
"cost": 2.5
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 0,
"access_type": "scan",
"resulting_rows": 0,
"cost": 2.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 0,
"cost_for_plan": 2.5,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "``.``",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "``.``"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"steps": [
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
SELECT * FROM t5 WHERE 5 IN (SELECT 1 FROM t6 WHERE d = ifnull(c,null) UNION SELECT 2 FROM t6 WHERE d = ifnull(c,null));
c
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT * FROM t5 WHERE 5 IN (SELECT 1 FROM t6 WHERE d = ifnull(c,null) UNION SELECT 2 FROM t6 WHERE d = ifnull(c,null)) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select 2 from `t6` where (`t6`.`d` = ifnull(`t5`.`c`,NULL))"
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"columns": 1,
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` from dual"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t5`.`c` AS `c` from `t5` where <in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 1)) union /* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 1)) union /* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 1)) union /* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 1)) union /* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 1)) union /* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t6`.`d` = ifnull(NULL,NULL)) and (<cache>(5) = 1))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` = ifnull(NULL,NULL)) and (<cache>(5) = 1))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` = NULL) and (<cache>(5) = 1))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE"
} /* empty_result */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 3,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t6`.`d` = ifnull(NULL,NULL)) and (<cache>(5) = 2))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` = ifnull(NULL,NULL)) and (<cache>(5) = 2))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` = NULL) and (<cache>(5) = 2))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE"
} /* empty_result */
} /* join_optimization */
},
{
"join_optimization": {
"select#": "fake",
"steps": [
{
"table_dependencies": [
{
"table": "``.``",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "``.``",
"table_scan": {
"rows": 0,
"cost": 2.5
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 0,
"access_type": "scan",
"resulting_rows": 0,
"cost": 2.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 0,
"cost_for_plan": 2.5,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": "fake",
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "``.``",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "``.``"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"steps": [
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
},
{
"condition_on_constant_tables": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where false union /* select#3 */ select 2 from `t6` where false))",
"condition_value": false
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE noticed after reading const tables"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
select (@query:=QUERY)+NULL, (@trace:=TRACE)+NULL from information_schema.OPTIMIZER_TRACE;
(@query:=QUERY)+NULL (@trace:=TRACE)+NULL
NULL NULL
Warnings:
Warning 1287 Setting user variables within expressions is deprecated and will be removed in a future release. Consider alternatives: 'SET variable=expression, ...', or 'SELECT expression(s) INTO variables(s)'.
Warning 1287 Setting user variables within expressions is deprecated and will be removed in a future release. Consider alternatives: 'SET variable=expression, ...', or 'SELECT expression(s) INTO variables(s)'.
select length(@trace);
length(@trace)
13882
set @max_mem_size=13807;
set optimizer_trace_max_mem_size=@max_mem_size;
select length(@query)+length(@trace) > @@optimizer_trace_max_mem_size;
length(@query)+length(@trace) > @@optimizer_trace_max_mem_size
1
SELECT * FROM t5 WHERE 5 IN (SELECT 1 FROM t6 WHERE d = ifnull(c,null) UNION SELECT 2 FROM t6 WHERE d = ifnull(c,null));
c
select (@missing_bytes:=missing_bytes_beyond_max_mem_size) from information_schema.OPTIMIZER_TRACE;
(@missing_bytes:=missing_bytes_beyond_max_mem_size)
202
Warnings:
Warning 1287 Setting user variables within expressions is deprecated and will be removed in a future release. Consider alternatives: 'SET variable=expression, ...', or 'SELECT expression(s) INTO variables(s)'.
select (@query2:=QUERY)+NULL,(@trace2:=TRACE)+NULL from information_schema.OPTIMIZER_TRACE;
(@query2:=QUERY)+NULL (@trace2:=TRACE)+NULL
NULL NULL
Warnings:
Warning 1287 Setting user variables within expressions is deprecated and will be removed in a future release. Consider alternatives: 'SET variable=expression, ...', or 'SELECT expression(s) INTO variables(s)'.
Warning 1287 Setting user variables within expressions is deprecated and will be removed in a future release. Consider alternatives: 'SET variable=expression, ...', or 'SELECT expression(s) INTO variables(s)'.
select length(@trace2),
(length(@trace2) + @missing_bytes) = length(@trace),
@query2 = @query;
length(@trace2) (length(@trace2) + @missing_bytes) = length(@trace) @query2 = @query
13680 1 1
select length(@query2) + length(@trace2)
between (@@optimizer_trace_max_mem_size-200) and (@@optimizer_trace_max_mem_size+200);
length(@query2) + length(@trace2)
between (@@optimizer_trace_max_mem_size-200) and (@@optimizer_trace_max_mem_size+200)
1
select instr(@trace, @trace2) = 1;
instr(@trace, @trace2) = 1
1
set optimizer_trace_max_mem_size=1;
select 1;
1
1
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select 1 521 0
set optimizer_trace_max_mem_size=0;
select 1;
1
1
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
529 0
set optimizer_trace_max_mem_size=1048576;
explain SELECT c FROM t5 where c+1 in (select d+1 from t6 where d is null);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t5 NULL system NULL NULL NULL NULL 1 100.00 NULL
1 SIMPLE t6 NULL ref d d 5 const 1 100.00 Using where; Using index; FirstMatch(t5)
Warnings:
Note 1003 /* select#1 */ select NULL AS `c` from <constant table> semi join (`test`.`t6`) where ((`test`.`t6`.`d` is null) and (<cache>((NULL + 1)) = (`test`.`t6`.`d` + 1)))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain SELECT c FROM t5 where c+1 in (select d+1 from t6 where d is null) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select (`t6`.`d` + 1) from `t6` where (`t6`.`d` is null)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t5`.`c` AS `c` from `t5` where (`t5`.`c` + 1) in (/* select#2 */ select (`t6`.`d` + 1) from `t6` where (`t6`.`d` is null))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "(`t5`.`c` + 1) in (/* select#2 */ select (`t6`.`d` + 1) from `t6` where (`t6`.`d` is null))",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))",
"decorrelated_predicates": [
{
"outer": "(`t5`.`c` + 1)",
"inner": "(`t6`.`d` + 1)"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t5`.`c` AS `c` from `t5` semi join (`t6`) where ((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t6`.`d` is null) and ((`t5`.`c` + 1) = (`t6`.`d` + 1)))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "NULL",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.4558,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "not_single_table"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"NULL <= d <= NULL"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": true,
"using_mrr": false,
"index_only": true,
"rows": 1,
"cost": 0.36,
"chosen": true
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 1,
"ranges": [
"NULL <= d <= NULL"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 1,
"cost_for_plan": 0.36,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* rows_estimation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "d",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "range",
"range_details": {
"used_index": "d"
} /* range_details */,
"chosen": false,
"cause": "heuristic_index_cheaper"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.35,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */
} /* execution_plan_for_potential_materialization */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t5`"
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "d",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "range",
"range_details": {
"used_index": "d"
} /* range_details */,
"chosen": false,
"cause": "heuristic_index_cheaper"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.35,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 0.35,
"rows": 1,
"chosen": true
},
{
"strategy": "MaterializeLookup",
"cost": 1.55,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 1.55,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t6`.`d` is null) and ((NULL + 1) = (`t6`.`d` + 1)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "((`t6`.`d` is null) and ((NULL + 1) = (`t6`.`d` + 1)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t6`",
"original_table_condition": "((`t6`.`d` is null) and ((NULL + 1) = (`t6`.`d` + 1)))",
"final_table_condition ": "((`t6`.`d` is null) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
set @old_opt_switch=@@optimizer_switch;
explain SELECT c FROM t5 where c+1 in (select d+1 from t6 where d is null);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL NULL NULL Not optimized, outer query is empty
Warnings:
Note 1003 /* select#1 */ select NULL AS `c` from dual where <in_optimizer>((NULL + 1),<exists>(/* select#2 */ select (`test`.`t6`.`d` + 1) from `test`.`t6` where ((`test`.`t6`.`d` is null) and (<cache>((NULL + 1)) = (`test`.`t6`.`d` + 1)))))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain SELECT c FROM t5 where c+1 in (select d+1 from t6 where d is null) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select (`t6`.`d` + 1) from `t6` where (`t6`.`d` is null)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t5`.`c` AS `c` from `t5` where <in_optimizer>((`t5`.`c` + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>((`t5`.`c` + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t5`.`c` + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t5`.`c` + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t5`.`c` + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"condition_on_constant_tables": "<in_optimizer>((NULL + 1),<exists>(/* select#2 */ select (`t6`.`d` + 1) from `t6` where ((`t6`.`d` is null) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))))",
"condition_value": false
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE noticed after reading const tables"
} /* empty_result */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
set optimizer_switch=@old_opt_switch;
CREATE TABLE t1 (s1 CHAR(5),
s2 CHAR(5)) CHARSET utf8mb4;
INSERT INTO t1 VALUES ('z','?'),('y','!');
explain select * from t1 where s1 > any (select s2 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where
2 SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`s1` AS `s1`,`test`.`t1`.`s2` AS `s2` from `test`.`t1` where <nop>((`test`.`t1`.`s1` > (/* select#2 */ select min(`test`.`t1`.`s2`) from `test`.`t1`)))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1 where s1 > any (select s2 from t1) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`s2` from `t1`"
},
{
"transformation": {
"select#": 2,
"from": "> ALL/ANY (SELECT)",
"to": "SELECT(MIN)",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`s1` AS `s1`,`t1`.`s2` AS `s2` from `t1` where <nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 50,
"rows_for_plan": 1,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))",
"final_table_condition ": "<nop>((`t1`.`s1` > (/* select#2 */ select min(`t1`.`s2`) from `t1`)))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain select * from t1 where s1 > any (select max(s2) from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where
2 SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`s1` AS `s1`,`test`.`t1`.`s2` AS `s2` from `test`.`t1` where <nop>((`test`.`t1`.`s1` > <min>(/* select#2 */ select max(`test`.`t1`.`s2`) from `test`.`t1`)))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1 where s1 > any (select max(s2) from t1) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select max(`t1`.`s2`) from `t1`"
},
{
"transformation": {
"select#": 2,
"from": "> ALL/ANY (SELECT)",
"to": "MIN (SELECT)",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`s1` AS `s1`,`t1`.`s2` AS `s2` from `t1` where <nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 50,
"rows_for_plan": 1,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))",
"final_table_condition ": "<nop>((`t1`.`s1` > <min>(/* select#2 */ select max(`t1`.`s2`) from `t1`)))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain select * from t1 where s1 in (select s2 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 2 100.00 Using where
2 DEPENDENT SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`s1` AS `s1`,`test`.`t1`.`s2` AS `s2` from `test`.`t1` where <in_optimizer>(`test`.`t1`.`s1`,<exists>(/* select#2 */ select 1 from `test`.`t1` where (<cache>(`test`.`t1`.`s1`) = `test`.`t1`.`s2`)))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1 where s1 in (select s2 from t1) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`s2` from `t1`"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`s1` AS `s1`,`t1`.`s2` AS `s2` from `t1` where <in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))",
"final_table_condition ": "<in_optimizer>(`t1`.`s1`,<exists>(/* select#2 */ select `t1`.`s2` from `t1` where (<cache>(`t1`.`s1`) = `t1`.`s2`)))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 50,
"rows_for_plan": 1,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(<cache>(`t1`.`s1`) = `t1`.`s2`)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(<cache>(`t1`.`s1`) = `t1`.`s2`)",
"final_table_condition ": "(<cache>(`t1`.`s1`) = `t1`.`s2`)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain select * from t1 where (s1,s2) in (select s2,s1 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 2 100.00 Using where
2 DEPENDENT SUBQUERY t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`s1` AS `s1`,`test`.`t1`.`s2` AS `s2` from `test`.`t1` where <in_optimizer>((`test`.`t1`.`s1`,`test`.`t1`.`s2`),<exists>(/* select#2 */ select 1,1 from `test`.`t1` where ((<cache>(`test`.`t1`.`s1`) = `test`.`t1`.`s2`) and (<cache>(`test`.`t1`.`s2`) = `test`.`t1`.`s1`))))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1 where (s1,s2) in (select s2,s1 from t1) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1`"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`s1` AS `s1`,`t1`.`s2` AS `s2` from `t1` where <in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))",
"final_table_condition ": "<in_optimizer>((`t1`.`s1`,`t1`.`s2`),<exists>(/* select#2 */ select `t1`.`s2`,`t1`.`s1` from `t1` where ((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.505
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.705,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 50,
"rows_for_plan": 1,
"cost_for_plan": 0.705,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))",
"final_table_condition ": "((<cache>(`t1`.`s1`) = `t1`.`s2`) and (<cache>(`t1`.`s2`) = `t1`.`s1`))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
set optimizer_switch=@old_opt_switch;
drop table t1;
create table t1(a int);
create table t2(a int);
insert into t1 values(1),(2),(3);
insert into t2 values(1),(2);
set @@session.optimizer_prune_level=0;
explain select * from t1,t2;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t2`
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1,t2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t2`.`a` AS `a` from `t1` join `t2`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7009,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7009,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 3,
"cost": 1.1013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 6,
"cost_for_plan": 1.8022,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 2,
"cost": 1.1009,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 6,
"cost_for_plan": 1.9022,
"pruned_by_cost": true
}
] /* rest_of_plan */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": null
},
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
},
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
select @@optimizer_trace_features;
@@optimizer_trace_features
greedy_search=on,range_optimizer=on,dynamic_range=on,repeated_subselect=on
set @@optimizer_trace_features="greedy_search=off";
explain select * from t1,t2;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 100.00 NULL
1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t2`
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from t1,t2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t2`.`a` AS `a` from `t1` join `t2`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": "..."
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": null
},
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
},
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
set @@optimizer_trace_features=default;
set @@session.optimizer_prune_level=default;
drop table t1, t2;
set @prefix_len = 6;
set @blob_len = 16;
set @suffix_len = @blob_len - @prefix_len;
create table t1_16 (a1 blob(16), a2 blob(16));
create table t2_16 (b1 blob(16), b2 blob(16));
create table t3_16 (c1 blob(16), c2 blob(16));
insert into t1_16 values
(concat('1 - 00', repeat('x', @suffix_len)), concat('2 - 00', repeat('x', @suffix_len)));
insert into t1_16 values
(concat('1 - 01', repeat('x', @suffix_len)), concat('2 - 01', repeat('x', @suffix_len)));
insert into t1_16 values
(concat('1 - 02', repeat('x', @suffix_len)), concat('2 - 02', repeat('x', @suffix_len)));
insert into t2_16 values
(concat('1 - 01', repeat('x', @suffix_len)), concat('2 - 01', repeat('x', @suffix_len)));
insert into t2_16 values
(concat('1 - 02', repeat('x', @suffix_len)), concat('2 - 02', repeat('x', @suffix_len)));
insert into t2_16 values
(concat('1 - 03', repeat('x', @suffix_len)), concat('2 - 03', repeat('x', @suffix_len)));
insert into t3_16 values
(concat('1 - 01', repeat('x', @suffix_len)), concat('2 - 01', repeat('x', @suffix_len)));
insert into t3_16 values
(concat('1 - 02', repeat('x', @suffix_len)), concat('2 - 02', repeat('x', @suffix_len)));
insert into t3_16 values
(concat('1 - 03', repeat('x', @suffix_len)), concat('2 - 03', repeat('x', @suffix_len)));
insert into t3_16 values
(concat('1 - 04', repeat('x', @suffix_len)), concat('2 - 04', repeat('x', @suffix_len)));
explain select left(a1,7), left(a2,7)
from t1_16
where a1 in (select b1 from t2_16 where b1 > '0');
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1_16 NULL ALL NULL NULL NULL NULL 3 100.00 Using where
2 DEPENDENT SUBQUERY t2_16 NULL ALL NULL NULL NULL NULL 3 33.33 Using where
Warnings:
Note 1003 /* select#1 */ select left(`test`.`t1_16`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_16`.`a2`,7) AS `left(a2,7)` from `test`.`t1_16` where <in_optimizer>(`test`.`t1_16`.`a1`,<exists>(/* select#2 */ select 1 from `test`.`t2_16` where ((`test`.`t2_16`.`b1` > '0') and (<cache>(`test`.`t1_16`.`a1`) = `test`.`t2_16`.`b1`))))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select left(a1,7), left(a2,7)
from t1_16
where a1 in (select b1 from t2_16 where b1 > '0') {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2_16`.`b1` from `t2_16` where (`t2_16`.`b1` > '0')"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select left(`t1_16`.`a1`,7) AS `left(a1,7)`,left(`t1_16`.`a2`,7) AS `left(a2,7)` from `t1_16` where <in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1_16`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1_16`",
"table_scan": {
"rows": 3,
"cost": 0.5073
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1_16`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8073,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8073,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1_16`",
"attached": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1_16`",
"original_table_condition": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))",
"final_table_condition ": "<in_optimizer>(`t1_16`.`a1`,<exists>(/* select#2 */ select `t2_16`.`b1` from `t2_16` where ((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1_16`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2_16`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2_16`",
"table_scan": {
"rows": 3,
"cost": 0.5073
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2_16`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8073,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8073,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "materialization",
"possible": false,
"cause": "inner blob"
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2_16`",
"attached": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2_16`",
"original_table_condition": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))",
"final_table_condition ": "((`t2_16`.`b1` > '0') and (<cache>(`t1_16`.`a1`) = `t2_16`.`b1`))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2_16`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
drop table t1_16,t2_16,t3_16;
set @@optimizer_switch=@old_opt_switch;
CREATE table t1 ( c1 integer );
INSERT INTO t1 VALUES ( 1 );
INSERT INTO t1 VALUES ( 2 );
INSERT INTO t1 VALUES ( 3 );
CREATE TABLE t2 ( c2 integer );
INSERT INTO t2 VALUES ( 1 );
INSERT INTO t2 VALUES ( 4 );
INSERT INTO t2 VALUES ( 5 );
SELECT * FROM t1 LEFT JOIN t2 ON c1 = c2
WHERE c2 IN ( SELECT c2 FROM t2 WHERE c2 IN ( 1 ) );
c1 c2
1 1
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT * FROM t1 LEFT JOIN t2 ON c1 = c2
WHERE c2 IN ( SELECT c2 FROM t2 WHERE c2 IN ( 1 ) ) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2`.`c2` from `t2` where (`t2`.`c2` = 1)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`c1` AS `c1`,`t2`.`c2` AS `c2` from (`t1` left join `t2` on((`t1`.`c1` = `t2`.`c2`))) where `t2`.`c2` in (/* select#2 */ select `t2`.`c2` from `t2` where (`t2`.`c2` = 1))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "`t2`.`c2` in (/* select#2 */ select `t2`.`c2` from `t2` where (`t2`.`c2` = 1))",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t2`.`c2` = 1) and (`t2`.`c2` = `t2`.`c2`))",
"decorrelated_predicates": [
{
"outer": "`t2`.`c2`",
"inner": "`t2`.`c2`"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin",
"outer_join_to_inner_join",
"JOIN_condition_to_WHERE",
"parenthesis_removal"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t1`.`c1` AS `c1`,`t2`.`c2` AS `c2` from `t1` join `t2` semi join (`t2`) where ((`t2`.`c2` = 1) and (`t2`.`c2` = `t2`.`c2`) and (`t1`.`c1` = `t2`.`c2`))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`c2` = 1) and (`t2`.`c2` = `t2`.`c2`) and (`t1`.`c1` = `t2`.`c2`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(multiple equal(1, `t2`.`c2`, `t2`.`c2`, `t1`.`c1`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(multiple equal(1, `t2`.`c2`, `t2`.`c2`, `t1`.`c1`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal(1, `t2`.`c2`, `t2`.`c2`, `t1`.`c1`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": true,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 2,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */
} /* execution_plan_for_potential_materialization */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8013,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.6026,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`",
"`t2`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 2.4039,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 2.4039,
"rows": 1,
"chosen": true
},
{
"strategy": "MaterializeLookup",
"cost": 3.6039,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 3.6039,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.6026,
"semijoin_strategy_choice": [
{
"strategy": "MaterializeScan",
"choice": "deferred"
}
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8013,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8013,
"semijoin_strategy_choice": [
{
"strategy": "MaterializeScan",
"choice": "deferred"
}
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t1`.`c1` = 1) and (`t2`.`c2` = 1) and (`t2`.`c2` = 1))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`c1` = 1)"
},
{
"table": "`t2`",
"attached": "(`t2`.`c2` = 1)"
},
{
"table": "`t2`",
"attached": "(`t2`.`c2` = 1)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(`t1`.`c1` = 1)",
"final_table_condition ": "(`t1`.`c1` = 1)"
},
{
"table": "`t2`",
"original_table_condition": "(`t2`.`c2` = 1)",
"final_table_condition ": "(`t2`.`c2` = 1)"
},
{
"table": "`t2`",
"original_table_condition": "(`t2`.`c2` = 1)",
"final_table_condition ": "(`t2`.`c2` = 1)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
},
{
"table": "`t2`",
"unknown_key_1": {
"constant_condition_in_bnl": "(`t2`.`c2` = 1)"
}
},
{
"table": "`t2`",
"unknown_key_2": {
"constant_condition_in_bnl": "(`t2`.`c2` = 1)"
}
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
SELECT * FROM t1 WHERE c1=5 UNION SELECT * FROM t2 WHERE c2=5;
c1
5
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT * FROM t1 WHERE c1=5 UNION SELECT * FROM t2 WHERE c2=5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`c1` AS `c1` from `t1` where (`t1`.`c1` = 5)"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2`.`c2` AS `c2` from `t2` where (`t2`.`c2` = 5)"
}
] /* steps */
} /* join_preparation */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"columns": 1,
"row_length": 5,
"key_length": 5,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `c1` AS `c1` from dual"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`c1` = 5)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal(5, `t1`.`c1`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal(5, `t1`.`c1`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal(5, `t1`.`c1`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t1`.`c1` = 5)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`c1` = 5)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(`t1`.`c1` = 5)",
"final_table_condition ": "(`t1`.`c1` = 5)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t2`.`c2` = 5)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal(5, `t2`.`c2`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal(5, `t2`.`c2`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal(5, `t2`.`c2`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t2`.`c2` = 5)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "(`t2`.`c2` = 5)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "(`t2`.`c2` = 5)",
"final_table_condition ": "(`t2`.`c2` = 5)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": "fake",
"steps": [
{
"table_dependencies": [
{
"table": "``.``",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "``.``",
"table_scan": {
"rows": 0,
"cost": 2.5
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 0,
"access_type": "scan",
"resulting_rows": 0,
"cost": 2.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 0,
"cost_for_plan": 2.5,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "``.``",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "``.``"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"steps": [
{
"materialize": {
"select#": 1,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
explain
select * from t1
where concat(c1,'x') IN
(select left(c2,8) from t2)
and
concat(c1,'y') IN
(select left(c2,9) from t2);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 NULL ALL NULL NULL NULL NULL 3 100.00 Using where
3 SUBQUERY t2 NULL ALL NULL NULL NULL NULL 3 100.00 NULL
2 SUBQUERY t2 NULL ALL NULL NULL NULL NULL 3 100.00 NULL
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`c1` AS `c1` from `test`.`t1` where (<in_optimizer>(concat(`test`.`t1`.`c1`,'x'),concat(`test`.`t1`.`c1`,'x') in ( <materialize> (/* select#2 */ select left(`test`.`t2`.`c2`,8) from `test`.`t2` where true ), <primary_index_lookup>(concat(`test`.`t1`.`c1`,'x') in <temporary table> on <auto_distinct_key> where ((concat(`test`.`t1`.`c1`,'x') = `materialized-subquery`.`left(c2,8)`))))) and <in_optimizer>(concat(`test`.`t1`.`c1`,'y'),concat(`test`.`t1`.`c1`,'y') in ( <materialize> (/* select#3 */ select left(`test`.`t2`.`c2`,9) from `test`.`t2` where true ), <primary_index_lookup>(concat(`test`.`t1`.`c1`,'y') in <temporary table> on <auto_distinct_key> where ((concat(`test`.`t1`.`c1`,'y') = `materialized-subquery`.`left(c2,9)`))))))
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain
select * from t1
where concat(c1,'x') IN
(select left(c2,8) from t2)
and
concat(c1,'y') IN
(select left(c2,9) from t2) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select left(`t2`.`c2`,8) from `t2`"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select left(`t2`.`c2`,9) from `t2`"
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`c1` AS `c1` from `t1` where (<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))",
"final_table_condition ": "(<in_optimizer>(concat(`t1`.`c1`,'x'),<exists>(/* select#2 */ select left(`t2`.`c2`,8) from `t2` where (<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8)))) and <in_optimizer>(concat(`t1`.`c1`,'y'),<exists>(/* select#3 */ select left(`t2`.`c2`,9) from `t2` where (<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9)))))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 3,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "materialization",
"has_nullable_expressions": true,
"treat_UNKNOWN_as_FALSE": true,
"possible": true
} /* transformation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */,
"subq_mat_decision": {
"parent_fanouts": [
{
"select#": 1,
"subq_attached_to_table": true,
"table": "`t1`",
"fanout": 3,
"cacheable": true
}
] /* parent_fanouts */,
"cost_to_create_and_fill_materialized_table": 2.1003,
"cost_of_one_EXISTS": 0.8003,
"number_of_subquery_evaluations": 3,
"cost_of_materialization": 2.4003,
"cost_of_EXISTS": 2.4008,
"chosen": true
} /* subq_mat_decision */
} /* execution_plan_for_potential_materialization */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "materialization",
"chosen": true,
"unknown_key_1": {
"creating_tmp_table": {
"tmp_table_info": {
"columns": 1,
"row_length": 38,
"key_length": 39,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
}
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 0.5013
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "materialization",
"has_nullable_expressions": true,
"treat_UNKNOWN_as_FALSE": true,
"possible": true
} /* transformation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8013,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8013,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */,
"subq_mat_decision": {
"parent_fanouts": [
{
"select#": 1,
"subq_attached_to_table": true,
"table": "`t1`",
"fanout": 3,
"cacheable": true
}
] /* parent_fanouts */,
"cost_to_create_and_fill_materialized_table": 2.1003,
"cost_of_one_EXISTS": 0.8003,
"number_of_subquery_evaluations": 3,
"cost_of_materialization": 2.4003,
"cost_of_EXISTS": 2.4008,
"chosen": true
} /* subq_mat_decision */
} /* execution_plan_for_potential_materialization */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "materialization",
"chosen": true,
"unknown_key_2": {
"creating_tmp_table": {
"tmp_table_info": {
"columns": 1,
"row_length": 34,
"key_length": 35,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
}
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"join_explain": {
"select#": 3,
"steps": [
] /* steps */
} /* join_explain */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
set optimizer_switch=@old_opt_switch;
DROP TABLE t1,t2;
create table t1 (a int);
insert into t1 values(1);
create table t2 (a int);
insert into t2 values(1);
select * from t1,t2;
a a
1 1
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select * from t1,t2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t2`.`a` AS `a` from `t1` join `t2`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
},
{
"table": "`t2`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
create table t3 (a int, b int);
create table t4 (a int primary key);
insert into t4 values(1),(2);
prepare stmt from 'select * from t3 where (a,a,b) in (select * from t1,t2,t4)';
select trace from information_schema.OPTIMIZER_TRACE;
trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4`"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` where (`t3`.`a`,`t3`.`a`,`t3`.`b`) in (/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4`)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "(`t3`.`a`,`t3`.`a`,`t3`.`b`) in (/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4`)",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))",
"decorrelated_predicates": [
{
"outer": "`t3`.`a`",
"inner": "`t1`.`a`"
},
{
"outer": "`t3`.`a`",
"inner": "`t2`.`a`"
},
{
"outer": "`t3`.`b`",
"inner": "`t4`.`a`"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` semi join (`t1` join `t2` join `t4`) where ((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
}
] /* steps */
}
execute stmt;
a b
select trace from information_schema.OPTIMIZER_TRACE;
trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` semi join (`t1` join `t2` join `t4`) where ((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t3`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 2,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t4`",
"row_may_be_null": false,
"map_bit": 3,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t4`",
"field": "a",
"equals": "`t3`.`b`",
"null_rejecting": true
}
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
{
"table": "`t4`",
"functionally_dependent": true
}
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t3`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": true
},
{
"table": "`t1`",
"table_scan": {
"rows": 1,
"cost": 0.5004
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 1,
"cost": 0.5004
} /* table_scan */
},
{
"table": "`t4`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
}
] /* rows_estimation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
] /* steps */
} /* execution_plan_for_potential_materialization */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.6004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.2009,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`",
"`t2`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`",
"`t1`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`",
"`t4`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"pruned_by_cost": true
}
] /* rest_of_plan */
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.6004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.1,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t4`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t4`",
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 1.3009,
"rows": 1,
"chosen": true
},
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`",
"`t4`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
}
] /* rest_of_plan */
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
}
execute stmt;
a b
select trace from information_schema.OPTIMIZER_TRACE;
trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t4` join `t3` semi join (`t1` join `t2`) where ((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t3`.`a` = `t1`.`a`) and (`t3`.`a` = `t2`.`a`) and (`t3`.`b` = `t4`.`a`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(multiple equal(`t3`.`a`, `t1`.`a`, `t2`.`a`) and multiple equal(`t3`.`b`, `t4`.`a`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t3`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 2,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t4`",
"row_may_be_null": false,
"map_bit": 3,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t4`",
"field": "a",
"equals": "`t3`.`b`",
"null_rejecting": true
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t3`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": true
},
{
"table": "`t1`",
"table_scan": {
"rows": 1,
"cost": 0.5004
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 1,
"cost": 0.5004
} /* table_scan */
},
{
"table": "`t4`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
}
] /* rows_estimation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
] /* steps */
} /* execution_plan_for_potential_materialization */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.6004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.2009,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`",
"`t2`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`",
"`t1`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t1`",
"`t4`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"pruned_by_cost": true
}
] /* rest_of_plan */
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.6004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"plan_prefix": [
"`t3`"
] /* plan_prefix */,
"table": "`t4`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "eq_ref",
"index": "PRIMARY",
"rows": 1,
"cost": 0.1,
"chosen": true
},
{
"access_type": "scan",
"cost": 0.7009,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.1,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t4`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t3`",
"`t4`",
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3009,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 1.3009,
"rows": 1,
"chosen": true
},
{
"strategy": "DuplicatesWeedout",
"cost": 2.5009,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t3`",
"`t4`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7004,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
}
] /* rest_of_plan */
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.6004,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
}
DROP TABLE t1,t2,t3,t4;
create table t1(a int);
insert into t1 values(1),(1);
create table t2(a int);
insert into t2 values(1),(1);
select * from t1 left join t2 on t2.a=500 where t2.a is NULL;
a a
1 NULL
1 NULL
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select * from t1 left join t2 on t2.a=500 where t2.a is NULL {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t2`.`a` AS `a` from (`t1` left join `t2` on((`t2`.`a` = 500))) where (`t2`.`a` is null)"
},
{
"transformations_to_nested_joins": {
"transformations": [
"parenthesis_removal"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t2`.`a` AS `a` from `t1` left join `t2` on((`t2`.`a` = 500)) where (`t2`.`a` is null)"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t2`.`a` is null)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t2`.`a` is null)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t2`.`a` is null)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t2`.`a` is null)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": true,
"map_bit": 1,
"depends_on_map_bits": [
0
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5009
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7009,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7009,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.5,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8009,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 1.5017,
"chosen": true
}
] /* rest_of_plan */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t2`.`a` is null)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
},
{
"table": "`t2`",
"attached": "(<if>(found_match(t2), (`t2`.`a` is null), true) and <if>(is_not_null_compl(t2), (`t2`.`a` = 500), true))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "(<if>(found_match(t2), (`t2`.`a` is null), true) and <if>(is_not_null_compl(t2), (`t2`.`a` = 500), true))",
"final_table_condition ": "(<if>(found_match(t2), (`t2`.`a` is null), true) and <if>(is_not_null_compl(t2), (`t2`.`a` = 500), true))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
},
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
drop table t1,t2;
create table t1(a int, b int);
insert into t1 values(1,NULL),(NULL,2);
create table t2(c int, d int);
insert into t2 values(1,1),(2,2);
select * from t1 where (t1.a,t1.b) not in (select c,d from t2 where c>0);
a b
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select * from t1 where (t1.a,t1.b) not in (select c,d from t2 where c>0) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where (`t2`.`c` > 0)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"chosen": true,
"evaluating_constant_where_conditions": [
] /* evaluating_constant_where_conditions */,
"evaluating_constant_having_conditions": [
] /* evaluating_constant_having_conditions */
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t1`.`b` AS `b` from `t1` where <in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7011,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7011,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)",
"final_table_condition ": "<in_optimizer>((`t1`.`a`,`t1`.`b`),<exists>(/* select#2 */ select `t2`.`c`,`t2`.`d` from `t2` where ((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true)) having (<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))) is false)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))"
}
] /* steps */
} /* condition_processing */
},
{
"condition_processing": {
"condition": "HAVING",
"original_condition": "(<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))",
"steps": [
{
"transformation": "constant_propagation",
"resulting_condition": "(<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(<if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`c`), true) and <if>(outer_field_is_not_null, <is_not_null_test>(`t2`.`d`), true))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.5,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.7011,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7011,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "materialization",
"has_nullable_expressions": true,
"treat_UNKNOWN_as_FALSE": false,
"possible": false,
"cause": "cannot_handle_partial_matches"
} /* transformation */
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))",
"final_table_condition ": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or (`t2`.`c` is null)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or (`t2`.`d` is null)), true))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
},
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
select t1.a,avg(t2.c) as moyenne from t1, t2 where t2.c>-1
group by t1.a having moyenne<>0;
a moyenne
1 1.5000
NULL 1.5000
select trace from information_schema.OPTIMIZER_TRACE;
trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,avg(`t2`.`c`) AS `moyenne` from `t1` join `t2` where (`t2`.`c` > -(1)) group by `t1`.`a` having (`moyenne` <> 0)"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t2`.`c` > -(1))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t2`.`c` > -(1))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t2`.`c` > -(1))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t2`.`c` > -(1))"
}
] /* steps */
} /* condition_processing */
},
{
"condition_processing": {
"condition": "HAVING",
"original_condition": "(`moyenne` <> 0)",
"steps": [
{
"transformation": "constant_propagation",
"resulting_condition": "(`moyenne` <> 0)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`moyenne` <> 0)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7011,
"chosen": true,
"use_tmp_table": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7011,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.5,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.8011,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 1.5022,
"sort_cost": 2,
"new_cost_for_plan": 3.5022,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.5,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.7011,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7011,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 2,
"cost": 0.7011,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 1.4022,
"sort_cost": 2,
"new_cost_for_plan": 3.4022,
"chosen": true
}
] /* rest_of_plan */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t2`.`c` > -(1))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "(`t2`.`c` > -(1))"
},
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
"simplifying_group_by": {
"original_clause": "`t1`.`a`",
"items": [
{
"item": "`t1`.`a`"
}
] /* items */,
"resulting_clause_is_simple": false,
"resulting_clause": "`t1`.`a`"
} /* simplifying_group_by */
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "(`t2`.`c` > -(1))",
"final_table_condition ": "(`t2`.`c` > <cache>(-(1)))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
},
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
{
"adding_tmp_table_in_plan_at_position": 2,
"write_method": "continuously_update_group_row"
}
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"temp_table_aggregate": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"in_plan_at_position": 2,
"columns": 2,
"row_length": 30,
"key_length": 5,
"unique_constraint": false,
"makes_grouped_rows": true,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
}
] /* steps */
} /* temp_table_aggregate */
}
] /* steps */
} /* join_execution */
}
] /* steps */
}
select t1.a,avg(t2.c) as moyenne from t1, t2 where t2.c>-1
group by t1.a having 4=5;
a moyenne
select trace from information_schema.OPTIMIZER_TRACE;
trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,avg(`t2`.`c`) AS `moyenne` from `t1` join `t2` where (`t2`.`c` > -(1)) group by `t1`.`a` having false"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t2`.`c` > -(1))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t2`.`c` > -(1))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t2`.`c` > -(1))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t2`.`c` > -(1))"
}
] /* steps */
} /* condition_processing */
},
{
"condition_processing": {
"condition": "HAVING",
"original_condition": "false",
"steps": [
{
"transformation": "constant_propagation",
"resulting_condition": "false"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */,
"empty_result": {
"cause": "Impossible HAVING"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
}
drop table t1,t2;
update t6 set d=5 where d is NULL;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
update t6 set d=5 where d is NULL {
"steps": [
{
"update_preparation": {
"select#": 1,
"steps": [
"update `t6` set `t6`.`d` = 5 where (`t6`.`d` is null)"
] /* steps */
} /* update_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` is null)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` is null)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` is null)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` is null)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "no_join"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "no_join"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"NULL <= d <= NULL"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": true,
"using_mrr": false,
"index_only": false,
"rows": 1,
"cost": 0.61,
"chosen": true
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 1,
"ranges": [
"NULL <= d <= NULL"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 1,
"cost_for_plan": 0.61,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* steps */
} 0 0
delete from t6 where d=5;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
delete from t6 where d=5 {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t6` where (`t6`.`d` = 5)"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = 5)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal(5, `t6`.`d`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal(5, `t6`.`d`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal(5, `t6`.`d`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8009
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "no_join"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "no_join"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"5 <= d <= 5"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": true,
"using_mrr": false,
"index_only": false,
"rows": 1,
"cost": 0.61,
"chosen": true
}
] /* range_scan_alternatives */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 1,
"ranges": [
"5 <= d <= 5"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 1,
"cost_for_plan": 0.61,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* steps */
} 0 0
insert into t6 values(6),(7),(8);
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
insert into t6 values(6),(7),(8) {
"steps": [
] /* steps */
} 0 0
insert into t6 select * from t6 where d>7;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
insert into t6 select * from t6 where d>7 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "insert into `t6` /* select#1 */ select sql_buffer_result `t6`.`d` AS `d` from `t6` where (`t6`.`d` > 7)"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` > 7)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` > 7)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` > 7)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` > 7)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9013
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.5616,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_group_by_or_distinct"
} /* group_index_range */,
"skip_scan_range": {
"potential_skip_scan_indexes": [
{
"index": "d",
"usable": false,
"cause": "prefix_not_const_equality"
}
] /* potential_skip_scan_indexes */
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"7 < d"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": true,
"rows": 2,
"cost": 0.4658,
"chosen": true
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 2,
"ranges": [
"7 < d"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 2,
"cost_for_plan": 0.4658,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "range",
"range_details": {
"used_index": "d"
} /* range_details */,
"resulting_rows": 2,
"cost": 0.6658,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.6658,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t6`.`d` > 7)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(`t6`.`d` > 7)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t6`",
"original_table_condition": "(`t6`.`d` > 7)",
"final_table_condition ": "(`t6`.`d` > 7)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
{
"adding_tmp_table_in_plan_at_position": 1,
"write_method": "write_all_rows"
}
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"in_plan_at_position": 1,
"columns": 1,
"row_length": 5,
"key_length": 0,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"materialize": {
"select#": 1,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
update t5, t6 set t6.d=t6.d+t5.c+4-t5.c-4 where d>7000;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
update t5, t6 set t6.d=t6.d+t5.c+4-t5.c-4 where d>7000 {
"steps": [
{
"update_preparation": {
"select#": 1,
"steps": [
"update `t5` join `t6` set `t6`.`d` = ((((`t6`.`d` + `t5`.`c`) + 4) - `t5`.`c`) - 4) where (`t6`.`d` > 7000)"
] /* steps */
} /* update_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` > 7000)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` > 7000)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` > 7000)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` > 7000)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 4,
"cost": 3.0017
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "not_single_table"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"7000 < d"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": false,
"rows": 1,
"cost": 0.61,
"chosen": true
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 1,
"ranges": [
"7000 < d"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 1,
"cost_for_plan": 0.61,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t5`"
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "range",
"range_details": {
"used_index": "d"
} /* range_details */,
"resulting_rows": 1,
"cost": 0.71,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.71,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t6`.`d` > 7000)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(`t6`.`d` > 7000)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"columns": 2,
"row_length": 12,
"key_length": 7,
"unique_constraint": false,
"makes_grouped_rows": true,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"finalizing_table_conditions": [
{
"table": "`t6`",
"original_table_condition": "(`t6`.`d` > 7000)",
"final_table_condition ": "(`t6`.`d` > 7000)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
delete t6 from t5, t6 where d>7000;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
delete t6 from t5, t6 where d>7000 {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete `t6` from `t5` join `t6` where (`t6`.`d` > 7000)"
] /* steps */
} /* delete_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` > 7000)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` > 7000)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` > 7000)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` > 7000)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t5`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 4,
"cost": 3.0017
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.6674,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "not_single_table"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"7000 < d"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": true,
"rows": 1,
"cost": 0.36,
"chosen": true
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */,
"chosen_range_access_summary": {
"range_access_plan": {
"type": "range_scan",
"index": "d",
"rows": 1,
"ranges": [
"7000 < d"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 1,
"cost_for_plan": 0.36,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t5`"
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 1,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "range",
"range_details": {
"used_index": "d"
} /* range_details */,
"resulting_rows": 1,
"cost": 0.46,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.46,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t6`.`d` > 7000)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(`t6`.`d` > 7000)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t6`",
"original_table_condition": "(`t6`.`d` > 7000)",
"final_table_condition ": "(`t6`.`d` > 7000)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set optimizer_trace_offset=2,optimizer_trace_limit=2;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select 1;
1
1
select 2;
2
2
select 3;
3
3
select 4;
4
4
select 5;
5
5
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select 3 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 3 AS `3`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
select 4 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 4 AS `4`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set optimizer_trace_offset=-2,optimizer_trace_limit=2;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select 1;
1
1
select 2;
2
2
select 3;
3
3
select 4;
4
4
select 5;
5
5
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select 4 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 4 AS `4`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
select 5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 5 AS `5`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set optimizer_trace_offset=default,optimizer_trace_limit=default;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
create table t1 (
id char(16) not null default '',
data int not null
) charset utf8mb4;
create table t2 (
s char(16),
i int,
d double
) charset utf8mb4;
insert into t1 values ("a", 1), ("b", 2) |
insert into t2 values ("a", 1, 1.0), ("b", 2, 2.0), ("c", 3, 3.0), ("d", 4, 4.0) |
create function f1() returns int
begin
declare ret int;
insert into t1 values("z",0);
delete from t1 where id="z";
select sum(data) into ret from t1;
return ret;
end|
select f1()|
f1()
3
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select s, f1() from t2 order by s desc|
s f1()
d 3
c 3
b 3
a 3
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select * from t6 where d in (select f1() from t2 where s="c")|
d
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set @old_opt_switch=@@optimizer_switch;
# Test was created when sj-mat-scan could not handle this query...
set optimizer_switch="materialization=off";
set optimizer_trace_offset=-60, optimizer_trace_limit=60|
select * from t6 where d in (select f1() from t2 where s="c")|
d
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select * from t6 where d in (select f1() from t2 where s="c") {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = 'c')"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` where `t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = 'c'))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "`t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = 'c'))",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))",
"decorrelated_predicates": [
{
"outer": "`t6`.`d`",
"inner": "`f1`()"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` semi join (`t2`) where ((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal('c', `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal('c', `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal('c', `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t6`",
"table_scan": {
"rows": 4,
"cost": 0.5017
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 4,
"cost": 0.5188
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 4,
"cost": 0.9017,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 25,
"rows_for_plan": 1,
"cost_for_plan": 0.9017,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t6`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.8205,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 1.8205,
"rows": 1,
"chosen": true
},
{
"strategy": "DuplicatesWeedout",
"cost": 3.0205,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.9188,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": null
},
{
"table": "`t2`",
"attached": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))",
"final_table_condition ": "((`t2`.`s` = 'c') and (`t6`.`d` = `f1`()))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
},
{
"table": "`t2`",
"unknown_key_1": {
"constant_condition_in_bnl": "(`t2`.`s` = 'c')"
}
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select count(*) from information_schema.OPTIMIZER_TRACE|
count(*)
21
set optimizer_trace_offset=3, optimizer_trace_limit=1|
select * from t6 where d in (select f1() from t2 where s="c")|
d
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
set @@optimizer_switch=@old_opt_switch;
# Stored procedures
create procedure p1(arg char(1) charset utf8mb4)
begin
declare res int;
select d into res from t6 where d in (select f1() from t2 where s=arg);
select d+1 into res from t6 where d=res+1;
end|
set @old_opt_switch=@@optimizer_switch;
# Test was created when sj-mat-scan could not handle this query...
set optimizer_switch="materialization=off";
set optimizer_trace_offset=0, optimizer_trace_limit=100;
call p1("c")|
Warnings:
Warning 1329 No data - zero rows fetched, selected, or processed
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
call p1("c") {
"steps": [
] /* steps */
} 0 0
set res@1 NULL {
"steps": [
] /* steps */
} 0 0
select d into res from t6 where d in (select f1() from t2 where s=arg) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` where `t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "`t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0))",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"decorrelated_predicates": [
{
"outer": "`t6`.`d`",
"inner": "`f1`()"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` semi join (`t2`) where ((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t6`",
"table_scan": {
"rows": 4,
"cost": 0.5017
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 4,
"cost": 0.5188
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 4,
"cost": 0.9017,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 25,
"rows_for_plan": 1,
"cost_for_plan": 0.9017,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t6`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.8205,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 1.8205,
"rows": 1,
"chosen": true
},
{
"strategy": "DuplicatesWeedout",
"cost": 3.0205,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.9188,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.25,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 0.9188,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": null
},
{
"table": "`t2`",
"attached": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"final_table_condition ": "((`t2`.`s` = <cache>(arg@0)) and (`t6`.`d` = `f1`()))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
},
{
"table": "`t2`",
"unknown_key_1": {
"constant_condition_in_bnl": "(`t2`.`s` = <cache>(arg@0))"
}
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select d+1 into res from t6 where d=res+1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select (`t6`.`d` + 1) AS `d+1` from `t6` where (`t6`.`d` = (res@1 + 1))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` = (res@1 + 1))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal((res@1 + 1), `t6`.`d`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal((res@1 + 1), `t6`.`d`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal((res@1 + 1), `t6`.`d`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t6`",
"field": "d",
"equals": "(res@1 + 1)",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 4,
"cost": 3.0017
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.6674,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
{
"impossible_condition": {
"cause": "comparison_with_null_always_false"
} /* impossible_condition */
}
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
}
] /* rows_estimation */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set @@optimizer_switch=@old_opt_switch;
# Triggers
create trigger trg1 before insert on t2 for each row
begin
set new.s=f1();
end|
set optimizer_trace_offset=0, optimizer_trace_limit=100|
insert into t2 select d,100,200 from t6 where d is not null|
select * from information_schema.OPTIMIZER_TRACE|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
insert into t2 select d,100,200 from t6 where d is not null {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "insert into `t2` /* select#1 */ select `t6`.`d` AS `d`,100 AS `100`,200 AS `200` from `t6` where (`t6`.`d` is not null)"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t6`.`d` is not null)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t6`.`d` is not null)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t6`.`d` is not null)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t6`.`d` is not null)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 4,
"cost": 3.0017
} /* table_scan */,
"potential_range_indexes": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indexes */,
"best_covering_index_scan": {
"index": "d",
"cost": 0.6674,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_group_by_or_distinct"
} /* group_index_range */,
"skip_scan_range": {
"potential_skip_scan_indexes": [
{
"index": "d",
"usable": false,
"cause": "prefix_not_const_equality"
}
] /* potential_skip_scan_indexes */
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "d",
"ranges": [
"NULL < d"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": true,
"rows": 4,
"cost": 0.6774,
"chosen": false,
"cause": "cost"
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */
} /* range_analysis */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"access_type": "scan",
"resulting_rows": 4,
"cost": 0.9017,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 4,
"cost_for_plan": 0.9017,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t6`.`d` is not null)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(`t6`.`d` is not null)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t6`",
"original_table_condition": "(`t6`.`d` is not null)",
"final_table_condition ": "(`t6`.`d` is not null)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set_trigger_field NEW.s:=`f1`() {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set_trigger_field NEW.s:=`f1`() {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set_trigger_field NEW.s:=`f1`() {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set_trigger_field NEW.s:=`f1`() {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select * from t2|
s i d
a 1 1
b 2 2
c 3 3
d 4 4
3 100 200
3 100 200
3 100 200
3 100 200
prepare stmt from 'select count(*) from t1 where t1.data=?';
set @param="c";
set optimizer_trace_offset=0, optimizer_trace_limit=100;
execute stmt using @param;
count(*)
0
Warnings:
Warning 1292 Truncated incorrect DOUBLE value: 'c'
select count(*) from information_schema.OPTIMIZER_TRACE;
count(*)
1
select TRACE into @trace from information_schema.OPTIMIZER_TRACE;
select @trace;
@trace
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select count(0) AS `count(*)` from `t1` where (`t1`.`data` = 'c')"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`data` = 'c')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t1`.`data` = 'c')"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t1`.`data` = 'c')"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t1`.`data` = 0)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t1`.`data` = 0)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`data` = 0)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(`t1`.`data` = 0)",
"final_table_condition ": "(`t1`.`data` = 0)"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
}
set optimizer_trace_offset=0, optimizer_trace_limit=100;
execute stmt using @param;
count(*)
0
Warnings:
Warning 1292 Truncated incorrect DOUBLE value: 'c'
select count(*) from information_schema.OPTIMIZER_TRACE;
count(*)
1
select TRACE into @trace2 from information_schema.OPTIMIZER_TRACE;
select @trace=@trace2;
@trace=@trace2
1
drop procedure p1;
create temporary table optt like information_schema.OPTIMIZER_TRACE;
create procedure p1(arg char(1) charset utf8mb4)
begin
declare res int;
set optimizer_trace="enabled=off";
# want to see all of SELECT below
set optimizer_trace_offset=0, optimizer_trace_limit=100;
set optimizer_trace="enabled=on";
select d into res from t6 where d in (select f1() from t2 where s=arg);
set optimizer_trace="enabled=off"; # and not more
insert into optt select * from information_schema.OPTIMIZER_TRACE;
set optimizer_trace_offset=default, optimizer_trace_limit=default;
select d+1 into res from t6 where d=res+1;
end|
call p1("c")|
Warnings:
Warning 1329 No data - zero rows fetched, selected, or processed
select * from optt|
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select d into res from t6 where d in (select f1() from t2 where s=arg) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0)"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` where `t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": true,
"transformation_to_semi_join": {
"subquery_predicate": "`t6`.`d` in (/* select#2 */ select `f1`() from `t2` where (`t2`.`s` = arg@0))",
"embedded in": "WHERE",
"evaluating_constant_semijoin_conditions": [
] /* evaluating_constant_semijoin_conditions */,
"semi-join condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"decorrelated_predicates": [
{
"outer": "`t6`.`d`",
"inner": "`f1`()"
}
] /* decorrelated_predicates */
} /* transformation_to_semi_join */
} /* transformation */
},
{
"transformations_to_nested_joins": {
"transformations": [
"semijoin"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` semi join (`t2`) where ((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t6`.`d` = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t6`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"pulled_out_semijoin_tables": [
] /* pulled_out_semijoin_tables */
},
{
"rows_estimation": [
{
"table": "`t6`",
"table_scan": {
"rows": 4,
"cost": 0.5017
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 8,
"cost": 0.5376
} /* table_scan */
}
] /* rows_estimation */
},
{
"execution_plan_for_potential_materialization": {
"steps": [
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 8,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.125,
"access_type": "scan",
"resulting_rows": 1,
"cost": 1.3376,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3376,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */
} /* execution_plan_for_potential_materialization */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 4,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 4,
"cost": 0.9017,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 25,
"rows_for_plan": 1,
"cost_for_plan": 0.9017,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t6`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 8,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.125,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 1.3376,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 2.2393,
"semijoin_strategy_choice": [
{
"strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 8,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.125,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 1.3376,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 2.2393,
"rows": 1,
"chosen": true
},
{
"strategy": "MaterializeLookup",
"cost": 3.4393,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 3.4393,
"rows": 1,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 8,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.125,
"access_type": "scan",
"resulting_rows": 1,
"cost": 1.3376,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 1.3376,
"semijoin_strategy_choice": [
{
"strategy": "MaterializeScan",
"choice": "deferred"
}
] /* semijoin_strategy_choice */,
"pruned_by_heuristic": true
},
{
"final_semijoin_strategy": "FirstMatch",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 8,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.125,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 1,
"cost": 1.3376,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": null
},
{
"table": "`t2`",
"attached": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t2`",
"original_table_condition": "((`t2`.`s` = arg@0) and (`t6`.`d` = `f1`()))",
"final_table_condition ": "((`t2`.`s` = <cache>(arg@0)) and (`t6`.`d` = `f1`()))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t6`"
},
{
"table": "`t2`",
"unknown_key_1": {
"constant_condition_in_bnl": "(`t2`.`s` = <cache>(arg@0))"
}
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
set ret@0 NULL {
"steps": [
] /* steps */
} 0 0
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
delete from t1 where id="z" {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
"delete from `t1` where (`t1`.`id` = 'z')"
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` = 'z')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('z', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
select sum(data) into ret from t1 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select sum(`t1`.`data`) AS `sum(data)` from `t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
freturn 3 ret@0 {
"steps": [
] /* steps */
} 0 0
select @@optimizer_trace|
@@optimizer_trace
enabled=off,one_line=off
set optimizer_trace="enabled=on";
drop temporary table optt;
drop function f1;
drop procedure p1;
drop trigger trg1;
create view v1 as select * from t1 where id < "c";
explain select * from v1 where id="b";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ALL NULL NULL NULL NULL 2 50.00 Using where
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`id` AS `id`,`test`.`t1`.`data` AS `data` from `test`.`t1` where (`test`.`t1`.`id` = 'b')
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from v1 where id="b" {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`id` AS `id`,`t1`.`data` AS `data` from `t1` where (`t1`.`id` < 'c')"
}
] /* steps */
} /* join_preparation */
},
{
"view": {
"table": "`v1`",
"select#": 2,
"merged": true
} /* view */
},
{
"expanded_query": "/* select#1 */ select `t1`.`id` AS `id`,`t1`.`data` AS `data` from <constant table> join (`t1`) on((`t1`.`id` < 'c')) where (`t1`.`id` = 'b')"
},
{
"transformations_to_nested_joins": {
"transformations": [
"JOIN_condition_to_WHERE",
"parenthesis_removal"
] /* transformations */,
"expanded_query": "/* select#1 */ select `t1`.`id` AS `id`,`t1`.`data` AS `data` from `t1` where ((`t1`.`id` = 'b') and (`t1`.`id` < 'c'))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t1`.`id` = 'b') and (`t1`.`id` < 'c'))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(('b' < 'c') and multiple equal('b', `t1`.`id`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(('b' < 'c') and multiple equal('b', `t1`.`id`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('b', `t1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 2,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.5,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.7126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t1`.`id` = 'b')",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`id` = 'b')"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(`t1`.`id` = 'b')",
"final_table_condition ": "(`t1`.`id` = 'b')"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
insert into v1 values("z", 100);
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
insert into v1 values("z", 100) {
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select straight_join `t1`.`id` AS `id`,`t1`.`data` AS `data` from `t1` where (`t1`.`id` < 'c')"
}
] /* steps */
} /* join_preparation */
},
{
"view": {
"table": "`v1`",
"select#": 2,
"merged": true
} /* view */
}
] /* steps */
} 0 0
delete from v1 where data=100;
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
delete from v1 where data=100 {
"steps": [
{
"delete_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select straight_join `t1`.`id` AS `id`,`t1`.`data` AS `data` from `t1` where (`t1`.`id` < 'c')"
}
] /* steps */
} /* join_preparation */
},
{
"view": {
"table": "`v1`",
"select#": 2,
"merged": true
} /* view */
},
"delete from (`t1`) on((`t1`.`id` < 'c')) where (`t1`.`data` = 100)",
{
"transformations_to_nested_joins": {
"transformations": [
"JOIN_condition_to_WHERE",
"parenthesis_removal"
] /* transformations */,
"expanded_query": "delete from (`t1`) where ((`t1`.`data` = 100) and (`t1`.`id` < 'c'))"
} /* transformations_to_nested_joins */
}
] /* steps */
} /* delete_preparation */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t1`.`data` = 100) and (`t1`.`id` < 'c'))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t1`.`id` < 'c') and multiple equal(100, `t1`.`data`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t1`.`id` < 'c') and multiple equal(100, `t1`.`data`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t1`.`id` < 'c') and multiple equal(100, `t1`.`data`))"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9126
} /* table_scan */
} /* range_analysis */
}
] /* steps */
} 0 0
drop view v1;
create view v1 as select * from t1 where id < "c" limit 2;
explain select * from v1 where id="b";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 PRIMARY <derived2> NULL ref <auto_key0> <auto_key0> 64 const 1 100.00 Using where
2 DERIVED t1 NULL ALL NULL NULL NULL NULL 3 33.33 Using where
Warnings:
Note 1003 /* select#1 */ select `v1`.`id` AS `id`,`v1`.`data` AS `data` from `test`.`v1` where (`v1`.`id` = 'b')
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from v1 where id="b" {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`id` AS `id`,`t1`.`data` AS `data` from `t1` where (`t1`.`id` < 'c') limit 2"
}
] /* steps */
} /* join_preparation */
},
{
"view": {
"table": "`v1`",
"select#": 2,
"materialized": true
} /* view */
},
{
"expanded_query": "/* select#1 */ select `v1`.`id` AS `id`,`v1`.`data` AS `data` from `v1` where (`v1`.`id` = 'b')"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`id` < 'c')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t1`.`id` < 'c')"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t1`.`id` < 'c')"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t1`.`id` < 'c')"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 0.5126
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.3333,
"access_type": "scan",
"resulting_rows": 1,
"cost": 0.8126,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.8126,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t1`.`id` < 'c')",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`id` < 'c')"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`t1`",
"original_table_condition": "(`t1`.`id` < 'c')",
"final_table_condition ": "(`t1`.`id` < 'c')"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`v1`.`id` = 'b')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "multiple equal('b', `v1`.`id`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "multiple equal('b', `v1`.`id`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "multiple equal('b', `v1`.`id`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`v1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`v1`",
"field": "id",
"equals": "'b'",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`v1`"
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`v1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "<auto_key0>",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "scan",
"cost": 2.725,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.35,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`v1`.`id` = 'b')",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`v1`",
"attached": "(`v1`.`id` = 'b')"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`v1`",
"original_table_condition": "(`v1`.`id` = 'b')",
"final_table_condition ": "(`v1`.`id` = 'b')"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`v1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "`v1`",
"in_plan_at_position": 0,
"columns": 2,
"row_length": 69,
"key_length": 64,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
drop view v1;
set end_markers_in_json=off;
select 1 union select 2;
1
1
2
select TRACE into dumpfile 'MYSQLTEST_VARDIR/tmp/optimizer_trace.txt' from information_schema.OPTIMIZER_TRACE;;
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 1 AS `1`"
}
]
}
},
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 2 AS `2`"
}
]
}
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"columns": 1,
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": true,
"location": "TempTable"
}
}
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` AS `1` from dual"
}
]
}
},
{
"join_optimization": {
"select#": 1,
"steps": [
]
}
},
{
"join_optimization": {
"select#": 2,
"steps": [
]
}
},
{
"join_optimization": {
"select#": "fake",
"steps": [
{
"table_dependencies": [
{
"table": "``.``",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
]
}
]
},
{
"rows_estimation": [
{
"table": "``.``",
"table_scan": {
"rows": 0,
"cost": 2.5
}
}
]
},
{
"considered_execution_plans": [
{
"plan_prefix": [
],
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 0,
"access_type": "scan",
"resulting_rows": 0,
"cost": 2.5,
"chosen": true
}
]
},
"condition_filtering_pct": 100,
"rows_for_plan": 0,
"cost_for_plan": 2.5,
"chosen": true
}
]
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
],
"attached_conditions_summary": [
{
"table": "``.``",
"attached": null
}
]
}
},
{
"finalizing_table_conditions": [
]
},
{
"refine_plan": [
{
"table": "``.``"
}
]
}
]
}
},
{
"join_execution": {
"steps": [
{
"materialize": {
"select#": 1,
"steps": [
]
}
},
{
"materialize": {
"select#": 2,
"steps": [
]
}
}
]
}
}
]
}set optimizer_switch='default,index_merge=on,index_merge=off,default';
ERROR 42000: Variable 'optimizer_switch' can't be set to the value of 'index_merge=off,default'
select @@optimizer_switch=@old_opt_switch;
@@optimizer_switch=@old_opt_switch
1
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select "abc1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111def" as col {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 'abc1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111def' AS `col`"
}
]
}
},
{
"join_optimization": {
"select#": 1,
"steps": [
]
}
},
{
"join_execution": {
"select#": 1,
"steps": [
]
}
}
]
} 0 0
drop table t1,t2;
DROP TABLE t5,t6;
set optimizer_trace=default;
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