GIF89a;
Mini Shell
Mini Shell
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_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"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`)"
}
]
}
},
{
"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": 4.5034
},
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
]
}
],
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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#": 2,
"steps": [
]
}
}
]
}
}
]
}
}
]
} 0 0
select (1-length(replace(TRACE, " ", ""))/length(TRACE))*100
from information_schema.OPTIMIZER_TRACE;
(1-length(replace(TRACE, " ", ""))/length(TRACE))*100
62.7018
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_execution": {"select#": 1,"steps": [{"subselect_execution": {"select#": 2,"steps": [{"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`)"}]}},{"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": 4.5034},"potential_range_indices": [{"index": "d","usable": true,"key_parts": ["d"]}],"best_covering_index_scan": {"index": "d","cost": 1.4233,"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#": 2,"steps": []}}]}}]}}]} 0 0
select (1-length(replace(TRACE, " ", ""))/length(TRACE))*100
from information_schema.OPTIMIZER_TRACE;
(1-length(replace(TRACE, " ", ""))/length(TRACE))*100
6.0651
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 type possible_keys key key_len ref rows Extra
1 PRIMARY t5 system NULL NULL NULL NULL 1 NULL
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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_explain": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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 */
},
{
"condition_on_constant_tables": "0",
"condition_value": false
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE noticed after reading const tables"
} /* empty_result */
} /* join_optimization */
},
{
"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_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"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 */
},
{
"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": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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#": 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",
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 116508
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"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_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"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 */
},
{
"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": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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 */
},
{
"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": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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#": 2,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_execution": {
"select#": 3,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` from dual"
}
] /* steps */
} /* join_preparation */
},
{
"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": 10
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 0,
"cost": 10,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 10,
"rows_for_plan": 0,
"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 */
},
{
"refine_plan": [
{
"table": "``.``",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": "fake",
"steps": [
] /* 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)) and (<cache>(5) = 1))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select 2 from `t6` where ((`t6`.`d` = ifnull(`t5`.`c`,NULL)) and (<cache>(5) = 2))"
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 116508
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"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 */
},
{
"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_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_execution": {
"select#": 3,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` from dual"
},
{
"transformation": {
"select#": "fake",
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"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": 10
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 0,
"cost": 10,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 10,
"rows_for_plan": 0,
"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 */
},
{
"refine_plan": [
{
"table": "``.``",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": "fake",
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
},
{
"condition_on_constant_tables": "<in_optimizer>(5,<exists>(/* select#2 */ select 1 from `t6` where 0 union /* select#3 */ select 2 from `t6` where 0))",
"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
select length(@trace);
length(@trace)
12663
set @max_mem_size=13900;
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
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 (@missing_bytes:=missing_bytes_beyond_max_mem_size) from information_schema.OPTIMIZER_TRACE;
(@missing_bytes:=missing_bytes_beyond_max_mem_size)
0
select (@query2:=QUERY)+NULL,(@trace2:=TRACE)+NULL from information_schema.OPTIMIZER_TRACE;
(@query2:=QUERY)+NULL (@trace2:=TRACE)+NULL
NULL NULL
select length(@trace2),
(length(@trace2) + @missing_bytes) = length(@trace),
@query2 = @query;
length(@trace2) (length(@trace2) + @missing_bytes) = length(@trace) @query2 = @query
12663 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)
0
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 type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 DEPENDENT SUBQUERY t6 ref d d 5 const 1 Using where; Using index
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 isnull(`t6`.`d`)"
},
{
"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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
}
] /* steps */
} /* condition_processing */
},
{
"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 (isnull(`t6`.`d`) 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_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
}
] /* steps */
} /* condition_processing */
},
{
"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": "NULL",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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 */,
"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": 2.21,
"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": [
{
"access_type": "ref",
"index": "d",
"rows": 1,
"cost": 1.2,
"chosen": true
},
{
"access_type": "scan",
"cost": 2.4,
"rows": 2,
"cause": "cost",
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 1.2,
"rows_for_plan": 1,
"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": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* 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 type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 DEPENDENT SUBQUERY t6 ref d d 5 const 1 Using where; Using index
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 isnull(`t6`.`d`)"
},
{
"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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) 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 (isnull(`t6`.`d`) and (<cache>((`t5`.`c` + 1)) = (`t6`.`d` + 1)))))"
}
] /* steps */
} /* condition_processing */
},
{
"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 (isnull(`t6`.`d`) 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_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
}
] /* steps */
} /* condition_processing */
},
{
"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": "NULL",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.4233,
"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 */,
"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": 2.21,
"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": [
{
"access_type": "ref",
"index": "d",
"rows": 1,
"cost": 1.2,
"chosen": true
},
{
"access_type": "scan",
"cost": 2.4,
"rows": 2,
"cause": "cost",
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 1.2,
"rows_for_plan": 1,
"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": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "(isnull(`t6`.`d`) and (<cache>((NULL + 1)) = (`t6`.`d` + 1)))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t6`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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));
INSERT INTO t1 VALUES ('z','?'),('y','!');
explain extended select * from t1 where s1 > any (select s2 from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
2 SUBQUERY t1 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 extended 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain extended select * from t1 where s1 > any (select max(s2) from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
2 SUBQUERY t1 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 extended 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain extended select * from t1 where s1 in (select s2 from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 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 extended 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
explain extended select * from t1 where (s1,s2) in (select s2,s1 from t1);
id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 100.00 Using where
2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 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 extended 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4054,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4054,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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 type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using join buffer (Block Nested Loop)
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": 2
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4034,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4034,
"rows_for_plan": 2,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"using_join_cache": true,
"rows": 3,
"cost": 3.2052,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 5.6086,
"rows_for_plan": 6,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"using_join_cache": true,
"rows": 2,
"cost": 3.2035,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 5.8087,
"rows_for_plan": 6,
"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 */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
},
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* 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 type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 2 NULL
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using join buffer (Block Nested Loop)
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": 2
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 2
} /* 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 */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
},
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* 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 extended 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 type possible_keys key key_len ref rows filtered Extra
1 PRIMARY t1_16 ALL NULL NULL NULL NULL 3 100.00 Using where
2 DEPENDENT SUBQUERY t2_16 ALL NULL NULL NULL NULL 3 100.00 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 extended 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1_16`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6293,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6293,
"rows_for_plan": 3,
"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 */
},
{
"refine_plan": [
{
"table": "`t1_16`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2_16`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6293,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6293,
"rows_for_plan": 3,
"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": "((`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 */
},
{
"refine_plan": [
{
"table": "`t2_16`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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) and (<cache>(`t2`.`c2`) = `t2`.`c2`))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* 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 <in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"transformations_to_nested_joins": {
"transformations": [
"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` where (<in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))) and (`t1`.`c1` = `t2`.`c2`))"
} /* transformations_to_nested_joins */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))) and (`t1`.`c1` = `t2`.`c2`))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))) and multiple equal(`t1`.`c1`, `t2`.`c2`))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))) and multiple equal(`t1`.`c1`, `t2`.`c2`))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`t2`.`c2`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))) and multiple equal(`t1`.`c1`, `t2`.`c2`))"
}
] /* steps */
} /* condition_processing */
},
{
"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_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"table_scan": {
"rows": 3,
"cost": 2
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 3,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"using_join_cache": true,
"rows": 3,
"cost": 3.8052,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 6.4104,
"rows_for_plan": 9,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"pruned_by_heuristic": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`c2` = `t1`.`c1`) and <in_optimizer>(`t1`.`c1`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`)))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "<in_optimizer>(`t1`.`c1`,<exists>(/* select#2 */ select `t2`.`c2` from `t2` where ((`t2`.`c2` = 1) and (<cache>(`t2`.`c2`) = `t2`.`c2`))))"
},
{
"table": "`t2`",
"attached": "(`t2`.`c2` = `t1`.`c1`)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
},
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`c2` = 1) and (<cache>(`t1`.`c1`) = `t2`.`c2`))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((<cache>(`t1`.`c1`) = 1) and multiple equal(1, `t2`.`c2`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((<cache>(`t1`.`c1`) = 1) and multiple equal(1, `t2`.`c2`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((<cache>(`t1`.`c1`) = 1) and multiple equal(1, `t2`.`c2`))"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`c2` = 1) and (<cache>(`t1`.`c1`) = 1))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "((`t2`.`c2` = 1) and (<cache>(`t1`.`c1`) = 1))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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 */
},
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* 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",
"row_length": 5,
"key_length": 5,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 209715
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"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 */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `c1` AS `c1` from dual"
}
] /* steps */
} /* join_preparation */
},
{
"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": 1,
"cost": 10
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 1,
"cost": 10.25,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 10.25,
"rows_for_plan": 1,
"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 */
},
{
"refine_plan": [
{
"table": "``.``",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": "fake",
"steps": [
] /* 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 type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
3 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 3 Using where
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 3 Using where
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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"chosen": true
}
] /* considered_execution_plans */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "EXISTS (CORRELATED SELECT)",
"put_1_in_SELECT_list": true
} /* transformation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "(<cache>(concat(`t1`.`c1`,'y')) = left(`t2`.`c2`,9))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 3,
"steps": [
] /* steps */
} /* join_explain */
},
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 3,
"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>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "(<cache>(concat(`t1`.`c1`,'x')) = left(`t2`.`c2`,8))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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": 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 `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` where <in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
}
] /* steps */
} /* join_preparation */
}
] /* steps */
}
execute stmt;
a b
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` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` where <in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
}
] /* steps */
} /* condition_processing */
},
{
"table_dependencies": [
{
"table": "`t3`",
"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": "`t3`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": true
}
] /* 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 */
}
execute stmt;
a b
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` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t3`.`a` AS `a`,`t3`.`b` AS `b` from `t3` where <in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>((`t3`.`a`,`t3`.`a`,`t3`.`b`),<exists>(/* select#2 */ select `t1`.`a`,`t2`.`a`,`t4`.`a` from `t1` join `t2` join `t4` where ((<cache>(`t3`.`a`) = `t1`.`a`) and (<cache>(`t3`.`a`) = `t2`.`a`) and (<cache>(`t3`.`b`) = `t4`.`a`))))"
}
] /* steps */
} /* condition_processing */
},
{
"table_dependencies": [
{
"table": "`t3`",
"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": "`t3`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": true
}
] /* 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 */
}
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 isnull(`t2`.`a`)"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"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 isnull(`t2`.`a`)"
} /* transformations_to_nested_joins */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "isnull(`t2`.`a`)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "isnull(`t2`.`a`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "isnull(`t2`.`a`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "isnull(`t2`.`a`)"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4034,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4034,
"rows_for_plan": 2,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"using_join_cache": true,
"rows": 2,
"cost": 2.8035,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 5.2069,
"rows_for_plan": 4,
"chosen": true
}
] /* rest_of_plan */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "isnull(`t2`.`a`)",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
},
{
"table": "`t2`",
"attached": "(<if>(found_match(t2), isnull(`t2`.`a`), true) and <if>(is_not_null_compl(t2), (`t2`.`a` = 500), true))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
},
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* 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) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a`,`t1`.`b` AS `b` from `t1` where (not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4044,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4044,
"rows_for_plan": 2,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(not(<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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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))))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), true))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), true))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), true))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4044,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4044,
"rows_for_plan": 2,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`c` > 0) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`a`) = `t2`.`c`) or isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), 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 isnull(`t2`.`c`)), true) and <if>(outer_field_is_not_null, ((<cache>(`t1`.`b`) = `t2`.`d`) or isnull(`t2`.`d`)), true))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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
NULL 1.5000
1 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 */
},
{
"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": 2
} /* table_scan */
},
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4044,
"chosen": true,
"use_tmp_table": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4044,
"rows_for_plan": 2,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"using_join_cache": true,
"rows": 2,
"cost": 2.8045,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 5.2089,
"rows_for_plan": 4,
"sort_cost": 4,
"new_cost_for_plan": 9.2089,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4044,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4044,
"rows_for_plan": 2,
"pruned_by_heuristic": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t2`.`c` > -(1))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": null
},
{
"table": "`t2`",
"attached": "(`t2`.`c` > -(1))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"clause_processing": {
"clause": "GROUP BY",
"original_clause": "`t1`.`a`",
"items": [
{
"item": "`t1`.`a`"
}
] /* items */,
"resulting_clause_is_simple": true,
"resulting_clause": "`t1`.`a`"
} /* clause_processing */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
},
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"row_length": 30,
"key_length": 5,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 34952
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"filesort_information": [
{
"direction": "asc",
"table": "intermediate_tmp_table",
"field": "a"
}
] /* filesort_information */,
"filesort_priority_queue_optimization": {
"usable": false,
"cause": "not applicable (no LIMIT)"
} /* filesort_priority_queue_optimization */,
"filesort_execution": [
] /* filesort_execution */,
"filesort_summary": {
"rows": 2,
"examined_rows": 2,
"number_of_tmp_files": 0,
"sort_buffer_size": "NNN",
"sort_mode": "<sort_key, rowid>"
} /* filesort_summary */
}
] /* 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 (4 = 5)"
}
] /* 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": "(4 = 5)",
"steps": [
{
"transformation": "constant_propagation",
"resulting_condition": "(4 = 5)"
},
{
"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": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "isnull(`t6`.`d`)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "isnull(`t6`.`d`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "isnull(`t6`.`d`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "isnull(`t6`.`d`)"
}
] /* steps */
} /* condition_processing */
},
{
"table": "`t6`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "no_join"
} /* group_index_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": 2.21,
"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": 2.21,
"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": [
{
"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": 4.5034
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "no_join"
} /* group_index_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": 2.21,
"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": 2.21,
"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": "/* select#1 */ select `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 */
},
{
"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": 4.7051
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.6465,
"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 */,
"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": 3.41,
"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": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.6051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6051,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "index_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"row_length": 5,
"key_length": 0,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 209715
} /* tmp_table_info */
} /* creating_tmp_table */
}
] /* 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": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t5` join `t6` where (`t6`.`d` > 7000)"
}
] /* steps */
} /* join_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 */
},
{
"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": 4.9068
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_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": 2.21,
"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": 2.21,
"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": [
{
"access_type": "range",
"rows": 1,
"cost": 2.41,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.41,
"rows_for_plan": 1,
"chosen": true
}
] /* considered_execution_plans */
},
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "intermediate_tmp_table",
"row_length": 12,
"key_length": 7,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 87381
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"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 */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "range"
}
] /* 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": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select NULL AS `NULL` from `t5` join `t6` where (`t6`.`d` > 7000)"
}
] /* steps */
} /* join_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 */
},
{
"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": 4.9068
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.8698,
"chosen": true
} /* best_covering_index_scan */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_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": 2.21,
"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": [
"`t5`"
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 1,
"cost": 2.8068,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.8068,
"rows_for_plan": 1,
"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 */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "table_scan"
}
] /* 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 2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 2 AS `2`"
}
] /* steps */
} /* join_preparation */
}
] /* steps */
} 0 0
select 2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 2 AS `2`"
}
] /* 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 5 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select 5 AS `5`"
}
] /* steps */
} /* join_preparation */
}
] /* 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
);
create table t2 (
s char(16),
i int,
d double
);
insert into t1 values ("a", 1), ("b", 2) |
insert into t2 values ("a", 1, 1.0), ("b", 2, 2.0), ("c", 3, 3.0) |
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()
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": 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 `t6`.`d` AS `d` from `t6` where <in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* join_preparation */
}
] /* steps */
} 0 0
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') and (<cache>(`t6`.`d`) = `f1`()))"
},
{
"transformation": {
"select#": 2,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t6`.`d` AS `d` from `t6` where <in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* condition_processing */
},
{
"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`",
"table_scan": {
"rows": 4,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 4,
"cost": 2.8068,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.8068,
"rows_for_plan": 4,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "index_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal('c', `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal('c', `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal('c', `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6212,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6212,
"rows_for_plan": 3,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "((`t2`.`s` = 'c') and (<cache>(`t6`.`d`) = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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 */
},
{
"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
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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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(*)
22
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
insert into t1 values("z",0) {
"steps": [
] /* steps */
} 0 0
set @@optimizer_switch=@old_opt_switch;
# Stored procedures
create procedure p1(arg char(1))
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": 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 `t6`.`d` AS `d` from `t6` where <in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* condition_processing */
},
{
"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`",
"table_scan": {
"rows": 4,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 4,
"cost": 2.8068,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.8068,
"rows_for_plan": 4,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "index_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6212,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6212,
"rows_for_plan": 3,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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 */
},
{
"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
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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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 */
},
{
"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": 4.9068
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.8698,
"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": "/* select#1 */ select `t6`.`d` AS `d`,100 AS `100`,200 AS `200` from `t6` where (`t6`.`d` is not null)"
}
] /* steps */
} /* join_preparation */
}
] /* steps */
} 0 0
insert into t2 select d,100,200 from t6 where d is not null {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* 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 */
},
{
"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": 4.9068
} /* table_scan */,
"potential_range_indices": [
{
"index": "d",
"usable": true,
"key_parts": [
"d"
] /* key_parts */
}
] /* potential_range_indices */,
"best_covering_index_scan": {
"index": "d",
"cost": 1.8698,
"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 */,
"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": 1.8798,
"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": [
{
"access_type": "scan",
"rows": 4,
"cost": 2.8068,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.8068,
"rows_for_plan": 4,
"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 */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "index_scan"
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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
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
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` = 'c')"
}
] /* steps */
} /* condition_processing */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`t1`.`data` = 'c')",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1`",
"attached": "(`t1`.`data` = 'c')"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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
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))
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": 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 `t6`.`d` AS `d` from `t6` where <in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* steps */
} /* condition_processing */
},
{
"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`",
"table_scan": {
"rows": 4,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t6`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 4,
"cost": 2.8068,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.8068,
"rows_for_plan": 4,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t6`",
"attached": "<in_optimizer>(`t6`.`d`,<exists>(/* select#2 */ select `f1`() from `t2` where ((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t6`",
"access_type": "index_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "((<cache>(`t6`.`d`) = `f1`()) and multiple equal(arg@0, `t2`.`s`))"
}
] /* steps */
} /* condition_processing */
},
{
"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": 7,
"cost": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 7,
"cost": 3.4496,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 3.4496,
"rows_for_plan": 7,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t2`",
"attached": "((`t2`.`s` = arg@0) and (<cache>(`t6`.`d`) = `f1`()))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`t2`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"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 */
},
{
"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
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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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": [
{
"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": 4.7154
} /* 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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* 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 type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using where
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from v1 where id="b" {
"steps": [
{
"view": {
"database": "test",
"view": "v1",
"in_select#": 1,
"select#": 2,
"merged": true
} /* view */
},
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `t1`.`id` AS `id`,`t1`.`data` AS `data` from (`t1`) where ((`t1`.`id` = 'b') and (`t1`.`id` < 'c'))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"transformations_to_nested_joins": {
"transformations": [
"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 */
},
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 2.4154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.4154,
"rows_for_plan": 2,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* 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": [
] /* 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": [
{
"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": 4.7154
} /* 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 type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ref <auto_key0> <auto_key0> 16 const 0 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 3 Using where
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
explain select * from v1 where id="b" {
"steps": [
{
"view": {
"database": "test",
"view": "v1",
"in_select#": 1,
"select#": 2,
"materialized": true
} /* view */
},
{
"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 */
},
{
"join_preparation": {
"select#": 1,
"steps": [
{
"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 */
},
{
"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": 2
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 3,
"cost": 2.6154,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 2.6154,
"rows_for_plan": 3,
"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 */
},
{
"refine_plan": [
{
"table": "`t1`",
"access_type": "table_scan"
}
] /* 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 */
},
{
"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": 0.2,
"cost": 0.24,
"chosen": true
},
{
"access_type": "scan",
"cost": 10.4,
"rows": 2,
"cause": "cost",
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 0.24,
"rows_for_plan": 0.2,
"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 */
},
{
"refine_plan": [
{
"table": "`v1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_explain": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "`v1`",
"row_length": 21,
"key_length": 16,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 49932
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_explain": {
"select#": 2,
"steps": [
] /* steps */
} /* join_explain */
}
] /* steps */
} /* join_explain */
}
] /* steps */
} 0 0
drop view v1;
select * from information_schema.session_variables where
VARIABLE_NAME="optimizer_trace";
VARIABLE_NAME VARIABLE_VALUE
OPTIMIZER_TRACE enabled=on,one_line=off
select * from information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select * from information_schema.session_variables where
VARIABLE_NAME="optimizer_trace" {
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"row_length": 3268,
"key_length": 0,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 320
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"join_preparation": {
"select#": 1,
"steps": [
{
"expanded_query": "/* select#1 */ select `information_schema`.`session_variables`.`VARIABLE_NAME` AS `VARIABLE_NAME`,`information_schema`.`session_variables`.`VARIABLE_VALUE` AS `VARIABLE_VALUE` from `information_schema`.`session_variables` where (`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')"
}
] /* steps */
} /* condition_processing */
},
{
"table_dependencies": [
{
"table": "`information_schema`.`session_variables`",
"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": "`information_schema`.`session_variables`",
"table_scan": {
"rows": 2,
"cost": 10
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`information_schema`.`session_variables`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 10.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"cost_for_plan": 10.5,
"rows_for_plan": 2,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`information_schema`.`session_variables`",
"attached": "(`information_schema`.`session_variables`.`VARIABLE_NAME` = 'optimizer_trace')"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"refine_plan": [
{
"table": "`information_schema`.`session_variables`",
"access_type": "table_scan"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
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",
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"location": "memory (heap)",
"row_limit_estimate": 116508
}
}
},
{
"join_optimization": {
"select#": 1,
"steps": [
]
}
},
{
"join_optimization": {
"select#": 2,
"steps": [
]
}
},
{
"join_execution": {
"select#": 1,
"steps": [
]
}
},
{
"join_execution": {
"select#": 2,
"steps": [
]
}
},
{
"join_preparation": {
"select#": "fake",
"steps": [
{
"expanded_query": "/* select#fake */ select `1` AS `1` from dual"
}
]
}
},
{
"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": 2,
"cost": 10
}
}
]
},
{
"considered_execution_plans": [
{
"plan_prefix": [
],
"table": "``.``",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "scan",
"rows": 2,
"cost": 10.5,
"chosen": true
}
]
},
"cost_for_plan": 10.5,
"rows_for_plan": 2,
"chosen": true
}
]
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
],
"attached_conditions_summary": [
{
"table": "``.``",
"attached": null
}
]
}
},
{
"refine_plan": [
{
"table": "``.``",
"access_type": "table_scan"
}
]
}
]
}
},
{
"join_execution": {
"select#": "fake",
"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;
./BlackJoker Mini Shell 1.0