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

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SET optimizer_trace_max_mem_size=1048576;
SET end_markers_in_json=on;
SET optimizer_trace="enabled=on,one_line=off";
CREATE TABLE t1 (a INT);
CREATE TABLE t2 (a INT, b INT);
INSERT INTO t1 VALUES (2);
INSERT INTO t2 VALUES (1,7),(2,7);
# Subselect execute is traced every time it is executed
SET @@optimizer_trace_features="greedy_search=off,repeated_subselect=on";
SELECT (SELECT a FROM t1 WHERE t1.a=t2.a), a FROM t2;
(SELECT a FROM t1 WHERE t1.a=t2.a) a
NULL 1
2 2
SELECT * FROM information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT (SELECT a FROM t1 WHERE t1.a=t2.a), a FROM t2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`a` from `t1` where (`t1`.`a` = `t2`.`a`)"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select `t1`.`a` from `t1` where (`t1`.`a` = `t2`.`a`)) AS `(SELECT a FROM t1 WHERE t1.a=t2.a)`,`t2`.`a` AS `a` from `t2`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* 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
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`a` = `t2`.`a`)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "('2' = `t2`.`a`)",
"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_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
# Subselect execute is traced only the first time it is executed
SET @@optimizer_trace_features="greedy_search=off,repeated_subselect=off";
SELECT (SELECT a FROM t1 WHERE t1.a=t2.a), a FROM t2;
(SELECT a FROM t1 WHERE t1.a=t2.a) a
NULL 1
2 2
SELECT * FROM information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT (SELECT a FROM t1 WHERE t1.a=t2.a), a FROM t2 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t1`.`a` from `t1` where (`t1`.`a` = `t2`.`a`)"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select `t1`.`a` from `t1` where (`t1`.`a` = `t2`.`a`)) AS `(SELECT a FROM t1 WHERE t1.a=t2.a)`,`t2`.`a` AS `a` from `t2`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t2`",
"table_scan": {
"rows": 2,
"cost": 0.5011
} /* 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
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t2`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(`t1`.`a` = `t2`.`a`)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(`t1`.`a` = `t2`.`a`)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"attaching_conditions_to_tables": {
"original_condition": "('2' = `t2`.`a`)",
"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_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
DROP TABLE t1,t2;
SET @@optimizer_trace_features="default";
CREATE TABLE t1 (a FLOAT(5,4) zerofill);
Warnings:
Warning 1681 The ZEROFILL attribute is deprecated and will be removed in a future release. Use the LPAD function to zero-pad numbers, or store the formatted numbers in a CHAR column.
Warning 1681 Specifying number of digits for floating point data types is deprecated and will be removed in a future release.
CREATE TABLE t2 (a FLOAT(5,4),b FLOAT(2,0));
Warnings:
Warning 1681 Specifying number of digits for floating point data types is deprecated and will be removed in a future release.
Warning 1681 Specifying number of digits for floating point data types is deprecated and will be removed in a future release.
SELECT t1.a
FROM t1
WHERE t1.a= (SELECT b FROM t2 LIMIT 1) AND NOT
t1.a= (SELECT a FROM t2 LIMIT 1) ;
a
SELECT * FROM information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT t1.a
FROM t1
WHERE t1.a= (SELECT b FROM t2 LIMIT 1) AND NOT
t1.a= (SELECT a FROM t2 LIMIT 1) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2`.`b` from `t2` limit 1"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select `t2`.`a` from `t2` limit 1"
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `t1`.`a` AS `a` from `t1` where ((`t1`.`a` = (/* select#2 */ select `t2`.`b` from `t2` limit 1)) and (`t1`.`a` <> (/* select#3 */ select `t2`.`a` from `t2` limit 1)))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t1`.`a` = (/* select#2 */ select `t2`.`b` from `t2` limit 1)) and (`t1`.`a` <> (/* select#3 */ select `t2`.`a` from `t2` limit 1)))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t2`",
"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#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* subselect_evaluation */,
"resulting_condition": "((NULL <> (/* select#3 */ select `t2`.`a` from `t2` limit 1)) and multiple equal((/* select#2 */ select NULL from `t2` limit 1), `t1`.`a`))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "((NULL <> (/* select#3 */ select `t2`.`a` from `t2` limit 1)) and multiple equal((/* select#2 */ select NULL from `t2` limit 1), `t1`.`a`))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */,
"empty_result": {
"cause": "Impossible WHERE"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
SELECT 1 FROM DUAL
WHERE NOT EXISTS
(SELECT * FROM t2 WHERE a = 50 AND b = 3);
1
1
SELECT * FROM information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT 1 FROM DUAL
WHERE NOT EXISTS
(SELECT * FROM t2 WHERE a = 50 AND b = 3) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 from `t2` where ((`t2`.`a` = 50) and (`t2`.`b` = 3))"
},
{
"transformation": {
"select#": 2,
"from": "EXISTS (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select 1 AS `1` from DUAL where exists(/* select#2 */ select 1 from `t2` where ((`t2`.`a` = 50) and (`t2`.`b` = 3))) is false"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "exists(/* select#2 */ select 1 from `t2` where ((`t2`.`a` = 50) and (`t2`.`b` = 3))) is false",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "exists(/* select#2 */ select 1 from `t2` where ((`t2`.`a` = 50) and (`t2`.`b` = 3))) is false"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "exists(/* select#2 */ select 1 from `t2` where ((`t2`.`a` = 50) and (`t2`.`b` = 3))) is false"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`t2`.`a` = 50) and (`t2`.`b` = 3))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "((`t2`.`a` = 50) and (`t2`.`b` = 3))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "((`t2`.`a` = 50) and (`t2`.`b` = 3))"
},
{
"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 */
}
] /* steps */
} /* subselect_execution */
}
] /* subselect_evaluation */,
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
SELECT 1 FROM DUAL WHERE NOT EXISTS (SELECT DISTINCT(a) FROM t2 GROUP BY a ORDER BY b);
1
1
SELECT * FROM information_schema.OPTIMIZER_TRACE;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
SELECT 1 FROM DUAL WHERE NOT EXISTS (SELECT DISTINCT(a) FROM t2 GROUP BY a ORDER BY b) {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select `t2`.`a` from `t2`"
},
{
"transformation": {
"select#": 2,
"from": "EXISTS (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select 1 AS `1` from DUAL where exists(/* select#2 */ select `t2`.`a` from `t2`) is false"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "exists(/* select#2 */ select `t2`.`a` from `t2`) is false",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "exists(/* select#2 */ select `t2`.`a` from `t2`) is false"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "exists(/* select#2 */ select `t2`.`a` from `t2`) is false"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t2`",
"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#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* subselect_evaluation */,
"resulting_condition": null
}
] /* steps */
} /* condition_processing */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
DROP TABLE t1,t2;
#
# BUG#12905521 - ASSERT IN OPT_TRACE_STMT::SYNTAX_ERROR ON SELECT
# DISTINCT/MIN/JOIN/SUBQ QUERY
#
CREATE TABLE t1 (
pk INTEGER,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM;
CREATE TABLE t2 (
pk INTEGER,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM;
CREATE TABLE t3 (
pk INTEGER,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_time_key TIME,
col_datetime_nokey DATETIME,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_time_key),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM;
CREATE TABLE t4 (
pk INTEGER,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_date_key DATE,
col_date_nokey DATE,
col_time_key TIME,
col_time_nokey TIME,
col_datetime_key DATETIME,
col_datetime_nokey DATETIME,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM;
INSERT IGNORE INTO t4 (
col_int_key,col_int_nokey,
col_date_key,col_date_nokey,
col_time_key,col_time_nokey,
col_datetime_key,col_datetime_nokey,
col_varchar_key,col_varchar_nokey
) VALUES
(8,7,'2008-10-02','2008-10-02','04:07:22.028954','04:07:22.028954','2001-10-08 00:00:00','2001-10-08 00:00:00','g','g');
Warnings:
Warning 1364 Field 'pk' doesn't have a default value
CREATE TABLE t5 (
pk INTEGER AUTO_INCREMENT,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_date_key DATE,
col_date_nokey DATE,
col_time_key TIME,
col_time_nokey TIME,
col_datetime_key DATETIME,
col_datetime_nokey DATETIME,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_int_key),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM;
INSERT INTO t5 (
col_int_key,col_int_nokey,
col_date_key,col_date_nokey,
col_time_key,col_time_nokey,
col_datetime_key,col_datetime_nokey,
col_varchar_key,col_varchar_nokey
) VALUES
(8,NULL,'2000-12-03','2000-12-03','22:55:23.019225','22:55:23.019225','2005-07-20 00:00:00','2005-07-20 00:00:00','x','x'),
(7,8,'2008-05-03','2008-05-03','10:19:31.050677','10:19:31.050677','2007-10-06 17:56:40.056051','2007-10-06 17:56:40.056051','d','d'),
(8,6,'2000-09-20','2000-09-20','14:11:27.044095','14:11:27.044095','2003-06-13 23:19:49.018300','2003-06-13 23:19:49.018300','c','c');
set @old_opt_switch=@@optimizer_switch;
select distinct
alias1.`col_varchar_key` as field1 ,alias1.`col_date_key` as
field2 ,( select min( sq1_alias1.`col_varchar_nokey` ) as sq1_field1 from ( t1
as sq1_alias1 inner join ( t5 as sq1_alias2 left join t5 as sq1_alias3 on
(sq1_alias3.`col_varchar_nokey` = sq1_alias2.`col_varchar_key` ) ) on
(sq1_alias3.`col_varchar_nokey` = sq1_alias2.`col_varchar_key` ) ) where
exists ( select distinct c_sq1_alias2.`col_int_nokey` as c_sq1_field1 from (
t3 as c_sq1_alias1 right join t4 as c_sq1_alias2 on (c_sq1_alias2.`col_int_nokey` = c_sq1_alias1.`pk` ) ) where
c_sq1_alias2.`col_varchar_key` = sq1_alias2.`col_varchar_nokey` ) ) as field3
,( select max( sq2_alias1.`pk` ) as sq2_field1 from t5 as sq2_alias1 ) as
field4 ,alias2.`col_varchar_nokey` as field5 ,alias2.`col_varchar_nokey` as
field6 from ( t5 as alias1 right outer join ( ( ( select sq3_alias2.* from ( t5 as sq3_alias1 ,t4 as sq3_alias2 ) ) as alias2 right join t4
as alias3 on (alias3.`col_varchar_key` = alias2.`col_varchar_key` ) ) ) on
(alias3.`col_int_key` = alias2.`pk` ) ) where ( alias1.`col_varchar_nokey` in
( select sq4_alias1.`col_varchar_key` as sq4_field1 from ( t3 as sq4_alias1
inner join ( t2 as sq4_alias2 right outer join t3 as sq4_alias3 on
(sq4_alias3.`pk` = sq4_alias2.`col_int_key` ) ) on
(sq4_alias3.`col_varchar_nokey` = sq4_alias2.`col_varchar_key` ) ) where
sq4_alias2.`col_int_key` < alias1.`col_int_nokey` and
sq4_alias3.`col_varchar_nokey` <> alias1.`col_varchar_key` ) ) and
alias1.`col_int_key` not in (214) group by field1,field2,field3,
field4,field5,field6;
field1 field2 field3 field4 field5 field6
select * from information_schema.optimizer_trace;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select distinct
alias1.`col_varchar_key` as field1 ,alias1.`col_date_key` as
field2 ,( select min( sq1_alias1.`col_varchar_nokey` ) as sq1_field1 from ( t1
as sq1_alias1 inner join ( t5 as sq1_alias2 left join t5 as sq1_alias3 on
(sq1_alias3.`col_varchar_nokey` = sq1_alias2.`col_varchar_key` ) ) on
(sq1_alias3.`col_varchar_nokey` = sq1_alias2.`col_varchar_key` ) ) where
exists ( select distinct c_sq1_alias2.`col_int_nokey` as c_sq1_field1 from (
t3 as c_sq1_alias1 right join t4 as c_sq1_alias2 on (c_sq1_alias2.`col_int_nokey` = c_sq1_alias1.`pk` ) ) where
c_sq1_alias2.`col_varchar_key` = sq1_alias2.`col_varchar_nokey` ) ) as field3
,( select max( sq2_alias1.`pk` ) as sq2_field1 from t5 as sq2_alias1 ) as
field4 ,alias2.`col_varchar_nokey` as field5 ,alias2.`col_varchar_nokey` as
field6 from ( t5 as alias1 right outer join ( ( ( select sq3_alias2.* from ( t5 as sq3_alias1 ,t4 as sq3_alias2 ) ) as alias2 right join t4
as alias3 on (alias3.`col_varchar_key` = alias2.`col_varchar_key` ) ) ) on
(alias3.`col_int_key` = alias2.`pk` ) ) where ( alias1.`col_varchar_nokey` in
( select sq4_alias1.`col_varchar_key` as sq4_field1 from ( t3 as sq4_alias1
inner join ( t2 as sq4_alias2 right outer join t3 as sq4_alias3 on
(sq4_alias3.`pk` = sq4_alias2.`col_int_key` ) ) on
(sq4_alias3.`col_varchar_nokey` = sq4_alias2.`col_varchar_key` ) ) where
sq4_alias2.`col_int_key` < alias1.`col_int_nokey` and
sq4_alias3.`col_varchar_nokey` <> alias1.`col_varchar_key` ) ) and
alias1.`col_int_key` not in (214) group by field1,field2,field3,
field4,field5,field6 {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select `c_sq1_alias2`.`col_int_nokey` AS `c_sq1_field1` from `t4` `c_sq1_alias2` left join `t3` `c_sq1_alias1` on((`c_sq1_alias2`.`col_int_nokey` = `c_sq1_alias1`.`pk`)) where (`c_sq1_alias2`.`col_varchar_key` = `sq1_alias2`.`col_varchar_nokey`)"
},
{
"transformation": {
"select#": 3,
"from": "EXISTS (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#2 */ select min(`sq1_alias1`.`col_varchar_nokey`) AS `sq1_field1` from `t1` `sq1_alias1` join `t5` `sq1_alias2` join `t5` `sq1_alias3` where (exists(/* select#3 */ select `c_sq1_alias2`.`col_int_nokey` AS `c_sq1_field1` from `t4` `c_sq1_alias2` left join `t3` `c_sq1_alias1` on((`c_sq1_alias2`.`col_int_nokey` = `c_sq1_alias1`.`pk`)) where (`c_sq1_alias2`.`col_varchar_key` = `sq1_alias2`.`col_varchar_nokey`)) and (`sq1_alias3`.`col_varchar_nokey` = `sq1_alias2`.`col_varchar_key`) and (`sq1_alias3`.`col_varchar_nokey` = `sq1_alias2`.`col_varchar_key`))"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 4,
"steps": [
{
"expanded_query": "/* select#4 */ select max(`sq2_alias1`.`pk`) AS `sq2_field1` from `t5` `sq2_alias1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 6,
"steps": [
{
"expanded_query": "/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`))"
},
{
"transformation": {
"select#": 6,
"from": "IN (SELECT)",
"to": "semijoin",
"chosen": false
} /* transformation */
}
] /* steps */
} /* join_preparation */
},
{
"expanded_query": "/* select#1 */ select `alias1`.`col_varchar_key` AS `field1`,`alias1`.`col_date_key` AS `field2`,(/* select#2 */ select min(`sq1_alias1`.`col_varchar_nokey`) AS `sq1_field1` from `t1` `sq1_alias1` join `t5` `sq1_alias2` join `t5` `sq1_alias3` where (exists(/* select#3 */ select `c_sq1_alias2`.`col_int_nokey` AS `c_sq1_field1` from `t4` `c_sq1_alias2` left join `t3` `c_sq1_alias1` on((`c_sq1_alias2`.`col_int_nokey` = `c_sq1_alias1`.`pk`)) where (`c_sq1_alias2`.`col_varchar_key` = `sq1_alias2`.`col_varchar_nokey`)) and (`sq1_alias3`.`col_varchar_nokey` = `sq1_alias2`.`col_varchar_key`) and (`sq1_alias3`.`col_varchar_nokey` = `sq1_alias2`.`col_varchar_key`))) AS `field3`,(/* select#4 */ select max(`sq2_alias1`.`pk`) AS `sq2_field1` from `t5` `sq2_alias1`) AS `field4`,`sq3_alias2`.`col_varchar_nokey` AS `field5`,`sq3_alias2`.`col_varchar_nokey` AS `field6` from `t4` `alias3` join `t5` `sq3_alias1` join `t4` `sq3_alias2` join `t5` `alias1` where (<in_optimizer>(`alias1`.`col_varchar_nokey`,<exists>(/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`)))) and (`alias1`.`col_int_key` <> 214) and (`alias3`.`col_int_key` = `sq3_alias2`.`pk`) and (`alias3`.`col_varchar_key` = `sq3_alias2`.`col_varchar_key`)) group by `field1`,`field2`,`field3`,`field4`,`field5`,`field6`"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<in_optimizer>(`alias1`.`col_varchar_nokey`,<exists>(/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`)))) and (`alias1`.`col_int_key` <> 214) and (`alias3`.`col_int_key` = `sq3_alias2`.`pk`) and (`alias3`.`col_varchar_key` = `sq3_alias2`.`col_varchar_key`))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`alias1`.`col_varchar_nokey`,<exists>(/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`)))) and (`alias1`.`col_int_key` <> 214) and multiple equal(`alias3`.`col_int_key`, `sq3_alias2`.`pk`) and multiple equal(`alias3`.`col_varchar_key`, `sq3_alias2`.`col_varchar_key`))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`alias1`.`col_varchar_nokey`,<exists>(/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`)))) and (`alias1`.`col_int_key` <> 214) and multiple equal(`alias3`.`col_int_key`, `sq3_alias2`.`pk`) and multiple equal(`alias3`.`col_varchar_key`, `sq3_alias2`.`col_varchar_key`))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<in_optimizer>(`alias1`.`col_varchar_nokey`,<exists>(/* select#6 */ select `sq4_alias1`.`col_varchar_key` AS `sq4_field1` from `t3` `sq4_alias1` join `t3` `sq4_alias3` join `t2` `sq4_alias2` where ((`sq4_alias2`.`col_int_key` < `alias1`.`col_int_nokey`) and (`sq4_alias3`.`col_varchar_nokey` <> `alias1`.`col_varchar_key`) and (<cache>(`alias1`.`col_varchar_nokey`) = `sq4_alias1`.`col_varchar_key`) and (`sq4_alias3`.`col_varchar_nokey` = `sq4_alias2`.`col_varchar_key`) and (`sq4_alias3`.`pk` = `sq4_alias2`.`col_int_key`)))) and (`alias1`.`col_int_key` <> 214) and multiple equal(`alias3`.`col_int_key`, `sq3_alias2`.`pk`) and multiple equal(`alias3`.`col_varchar_key`, `sq3_alias2`.`col_varchar_key`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t5` `alias1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t5` `sq3_alias1`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t4` `sq3_alias2`",
"row_may_be_null": false,
"map_bit": 2,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t4` `alias3`",
"row_may_be_null": false,
"map_bit": 3,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t4` `sq3_alias2`",
"field": "pk",
"equals": "`alias3`.`col_int_key`",
"null_rejecting": true
},
{
"table": "`t4` `sq3_alias2`",
"field": "col_varchar_key",
"equals": "`alias3`.`col_varchar_key`",
"null_rejecting": true
},
{
"table": "`t4` `alias3`",
"field": "col_varchar_key",
"equals": "`sq3_alias2`.`col_varchar_key`",
"null_rejecting": true
},
{
"table": "`t4` `alias3`",
"field": "col_int_key",
"equals": "`sq3_alias2`.`pk`",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t5` `alias1`",
"range_analysis": {
"table_scan": {
"rows": 3,
"cost": 2.9085
} /* table_scan */,
"potential_range_indexes": [
{
"index": "PRIMARY",
"usable": false,
"cause": "not_applicable"
},
{
"index": "col_int_key",
"usable": true,
"key_parts": [
"col_int_key"
] /* key_parts */
},
{
"index": "col_varchar_key",
"usable": false,
"cause": "not_applicable"
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"impossible_range": true
} /* range_analysis */,
"rows": 0,
"cause": "impossible_where_condition"
},
{
"table": "`t5` `sq3_alias1`",
"table_scan": {
"rows": 3,
"cost": 0.5085
} /* table_scan */
},
{
"table": "`t4` `sq3_alias2`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
},
{
"table": "`t4` `alias3`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": false
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
"`t4` `sq3_alias2`",
"`t4` `alias3`",
"`t5` `alias1`"
] /* plan_prefix */,
"table": "`t5` `sq3_alias1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 3,
"access_type": "scan",
"resulting_rows": 3,
"cost": 0.8085,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 3,
"cost_for_plan": 0.8085,
"chosen": true
}
] /* considered_execution_plans */
}
] /* steps */,
"empty_result": {
"cause": "no matching row in const table"
} /* empty_result */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} 0 0
set optimizer_switch=@old_opt_switch;
drop table t1,t2,t3,t4,t5;
#
# BUG#12905758 - ASSERT IN OPT_TRACE_STMT::SYNTAX_ERROR ON
# SELECT/SUBQ/SUM QUERY
#
CREATE TABLE t1 (
pk INTEGER AUTO_INCREMENT,
col_int_nokey INTEGER,
col_int_key INTEGER,
col_date_key DATE,
col_date_nokey DATE,
col_time_key TIME,
col_time_nokey TIME,
col_datetime_key DATETIME,
col_datetime_nokey DATETIME,
col_varchar_key VARCHAR(1),
col_varchar_nokey VARCHAR(1),
PRIMARY KEY (pk),
KEY (col_varchar_key,col_int_key)
) ENGINE=MYISAM, CHARSET utf8mb4;
INSERT INTO t1 (
col_int_key,col_int_nokey,
col_date_key,col_date_nokey,
col_time_key,col_time_nokey,
col_datetime_key,col_datetime_nokey,
col_varchar_key,col_varchar_nokey
) VALUES
(8,NULL,'2000-12-03','2000-12-03','22:55:23.019225','22:55:23.019225','2005-07-20 00:00:00','2005-07-20 00:00:00','x','x'),
(8,6,'2000-09-20','2000-09-20','14:11:27.044095','14:11:27.044095','2003-06-13 23:19:49.018300','2003-06-13 23:19:49.018300','c','c');
CREATE TABLE t2 (I INTEGER);
select ( select sum( subquery1_t1.`col_int_nokey` ) as subquery1_field1 from
t1 as subquery1_t1 ) as field1 from ( t1 as table1 straight_join t1 as table2
on (table2.`col_varchar_key` = table1.`col_varchar_key` ) ) where (
table2.`col_int_nokey` <> any ( select 5 from t2 ) ) and table1.`pk` in
(192,18) order by field1 desc;
field1
select * from information_schema.optimizer_trace;
QUERY TRACE MISSING_BYTES_BEYOND_MAX_MEM_SIZE INSUFFICIENT_PRIVILEGES
select ( select sum( subquery1_t1.`col_int_nokey` ) as subquery1_field1 from
t1 as subquery1_t1 ) as field1 from ( t1 as table1 straight_join t1 as table2
on (table2.`col_varchar_key` = table1.`col_varchar_key` ) ) where (
table2.`col_int_nokey` <> any ( select 5 from t2 ) ) and table1.`pk` in
(192,18) order by field1 desc {
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select sum(`subquery1_t1`.`col_int_nokey`) AS `subquery1_field1` from `t1` `subquery1_t1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)"
}
] /* steps */
} /* join_preparation */
},
{
"IN_uses_bisection": true
},
{
"expanded_query": "/* select#1 */ select (/* select#2 */ select sum(`subquery1_t1`.`col_int_nokey`) AS `subquery1_field1` from `t1` `subquery1_t1`) AS `field1` from `t1` `table1` straight_join `t1` `table2` where (<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)) and (`table2`.`col_varchar_key` = `table1`.`col_varchar_key`)) order by `field1` desc"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "(<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)) and (`table2`.`col_varchar_key` = `table1`.`col_varchar_key`))",
"steps": [
{
"transformation": "equality_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)) and multiple equal(`table2`.`col_varchar_key`, `table1`.`col_varchar_key`))"
},
{
"transformation": "constant_propagation",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)) and multiple equal(`table2`.`col_varchar_key`, `table1`.`col_varchar_key`))"
},
{
"transformation": "trivial_condition_removal",
"subselect_evaluation": [
] /* subselect_evaluation */,
"resulting_condition": "(<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)) and multiple equal(`table2`.`col_varchar_key`, `table1`.`col_varchar_key`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t1` `table1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`t1` `table2`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
0
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`t1` `table1`",
"field": "col_varchar_key",
"equals": "`table2`.`col_varchar_key`",
"null_rejecting": true
},
{
"table": "`t1` `table2`",
"field": "col_varchar_key",
"equals": "`table1`.`col_varchar_key`",
"null_rejecting": true
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t1` `table1`",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8056
} /* table_scan */,
"potential_range_indexes": [
{
"index": "PRIMARY",
"usable": true,
"key_parts": [
"pk"
] /* key_parts */
},
{
"index": "col_varchar_key",
"usable": false,
"cause": "not_applicable"
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "not_single_table"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "PRIMARY",
"ranges": [
"18 <= pk <= 18",
"192 <= pk <= 192"
] /* ranges */,
"index_dives_for_eq_ranges": true,
"rowid_ordered": false,
"using_mrr": false,
"index_only": false,
"rows": 2,
"cost": 1.21,
"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": "PRIMARY",
"rows": 2,
"ranges": [
"18 <= pk <= 18",
"192 <= pk <= 192"
] /* ranges */
} /* range_access_plan */,
"rows_for_plan": 2,
"cost_for_plan": 1.21,
"chosen": true
} /* chosen_range_access_summary */
} /* range_analysis */
},
{
"table": "`t1` `table2`",
"table_scan": {
"rows": 2,
"cost": 0.5056
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1` `table1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "col_varchar_key",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "range",
"range_details": {
"used_index": "PRIMARY"
} /* range_details */,
"resulting_rows": 2,
"cost": 1.41,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 1.41,
"rest_of_plan": [
{
"plan_prefix": [
"`t1` `table1`"
] /* plan_prefix */,
"table": "`t1` `table2`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "col_varchar_key",
"rows": 2,
"cost": 1.4,
"chosen": true
},
{
"rows_to_scan": 2,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 2,
"cost": 0.9057,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 4,
"cost_for_plan": 2.3157,
"chosen": true
}
] /* rest_of_plan */
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`table2`.`col_varchar_key` = `table1`.`col_varchar_key`) and <nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))) and (`table1`.`pk` in (192,18)))",
"attached_conditions_computation": [
{
"table": "`t1` `table2`",
"rechecking_index_usage": {
"recheck_reason": "not_first_table",
"range_analysis": {
"table_scan": {
"rows": 2,
"cost": 2.8056
} /* table_scan */,
"potential_range_indexes": [
{
"index": "PRIMARY",
"usable": false,
"cause": "not_applicable"
},
{
"index": "col_varchar_key",
"usable": true,
"key_parts": [
"col_varchar_key",
"col_int_key"
] /* key_parts */
}
] /* potential_range_indexes */,
"setup_range_conditions": [
] /* setup_range_conditions */,
"group_index_range": {
"chosen": false,
"cause": "not_single_table"
} /* group_index_range */,
"skip_scan_range": {
"chosen": false,
"cause": "not_single_table"
} /* skip_scan_range */,
"analyzing_range_alternatives": {
"range_scan_alternatives": [
{
"index": "col_varchar_key",
"chosen": false,
"cause": "depends_on_unread_values"
}
] /* range_scan_alternatives */,
"analyzing_roworder_intersect": {
"usable": false,
"cause": "too_few_roworder_scans"
} /* analyzing_roworder_intersect */
} /* analyzing_range_alternatives */
} /* range_analysis */
} /* rechecking_index_usage */
}
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1` `table1`",
"attached": "(`table1`.`pk` in (192,18))"
},
{
"table": "`t1` `table2`",
"attached": "((`table2`.`col_varchar_key` = `table1`.`col_varchar_key`) and <nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))))"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
"simplifying_order_by": {
"original_clause": "`field1` desc",
"items": [
{
"item": "(/* select#2 */ select sum(`subquery1_t1`.`col_int_nokey`) AS `subquery1_field1` from `t1` `subquery1_t1`)",
"subselect_evaluation": [
{
"subselect_execution": {
"select#": 2,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
{
"table_dependencies": [
{
"table": "`t1` `subquery1_t1`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"rows_estimation": [
{
"table": "`t1` `subquery1_t1`",
"table_scan": {
"rows": 2,
"cost": 0.5056
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1` `subquery1_t1`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 2,
"access_type": "scan",
"resulting_rows": 2,
"cost": 0.7056,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 2,
"cost_for_plan": 0.7056,
"chosen": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": null,
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`t1` `subquery1_t1`",
"attached": null
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"optimizing_distinct_group_by_order_by": {
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1` `subquery1_t1`"
}
] /* refine_plan */
},
{
"considering_tmp_tables": [
] /* considering_tmp_tables */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 2,
"steps": [
] /* steps */
} /* join_execution */
}
] /* steps */
} /* subselect_execution */
}
] /* subselect_evaluation */,
"uses_only_constant_tables": true
}
] /* items */,
"resulting_clause_is_simple": true,
"resulting_clause": ""
} /* simplifying_order_by */
} /* optimizing_distinct_group_by_order_by */
},
{
"finalizing_table_conditions": [
{
"table": "`t1` `table1`",
"original_table_condition": "(`table1`.`pk` in (192,18))",
"final_table_condition ": "(`table1`.`pk` in (192,18))"
},
{
"table": "`t1` `table2`",
"original_table_condition": "((`table2`.`col_varchar_key` = `table1`.`col_varchar_key`) and <nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))))",
"final_table_condition ": "((`table2`.`col_varchar_key` = `table1`.`col_varchar_key`) and <nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)))))"
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`t1` `table1`",
"pushed_index_condition": "(`table1`.`pk` in (192,18))",
"table_condition_attached": null
},
{
"table": "`t1` `table2`",
"unknown_key_1": {
"constant_condition_in_bnl": "<nop>(<in_optimizer>(`table2`.`col_int_nokey`,<exists>(/* select#3 */ select 5 from `t2` where <if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true))))"
}
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 3,
"steps": [
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "<if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "<if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)"
},
{
"transformation": "constant_propagation",
"resulting_condition": "<if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "<if>(outer_field_is_not_null, (<cache>(`table2`.`col_int_nokey`) <> 5), true)"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`t2`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`t2`",
"rows": 1,
"cost": 1,
"table_type": "system",
"empty": true
}
] /* rows_estimation */
},
{
"transformation": {
"select#": 3,
"from": "IN (SELECT)",
"to": "materialization",
"possible": false,
"cause": "not an IN predicate"
} /* transformation */
}
] /* 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
drop table t1,t2;
#
# Tracing of semijoin loosescan
#
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int, b int, filler char(100), key(a,b)) charset utf8mb4;
insert into t1 select A.a, B.a, 'filler' from t0 A, t0 B;
create table t2 as select * from t1;
set @old_opt_switch=@@optimizer_switch;
set optimizer_switch="firstmatch=off,materialization=off,duplicateweedout=off";
set @old_opt_prune_level=@@optimizer_prune_level;
set optimizer_prune_level=0;
explain select * from t2 where a in (select b from t1 where a=3);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ref a a 5 const 8 100.00 Using index; LooseScan
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 10.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = 3))
# Equality-propagation involving inner field => 1st sj equality is bound
explain select * from t2 where (b+0,a+0) in (select a,b from t1 where a=3);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ref a a 5 const 8 100.00 Using index; LooseScan
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 100.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = 3) and ((`test`.`t2`.`b` + 0) = 3) and ((`test`.`t2`.`a` + 0) = `test`.`t1`.`b`))
# Equality-propagation involving outer field => 3rd sj equality is bound.
explain select * from t2 where (b,a,filler) in (select a,b,a*3 from t1) and filler='abc';
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL index a a 10 NULL 100 100.00 Using index; LooseScan
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 1.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t1`.`a`) and (`test`.`t2`.`filler` = 'abc') and (`test`.`t2`.`filler` = (`test`.`t1`.`a` * 3)))
SELECT show_json_object('"recalculate_access_paths_and_cost": {', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"recalculate_access_paths_and_cost": {', TRACE)
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_1": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"covering_scan": {
"cost": 1.0484,
"chosen": true
} /* covering_scan */
}
] /* indexes */
} /* searching_loose_scan_index */
}
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 0.1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 10,
"cost": 112.04,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
}
# Remove the condition on 'filler' => 3rd sj equality is not bound.
explain select * from t2 where (b,a,filler) in (select a,b,a*3 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 100.00 Using where
1 SIMPLE t1 NULL ref a a 10 test.t2.b,test.t2.a 1 100.00 Using index; Start temporary; End temporary
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`b` = `test`.`t2`.`a`) and (`test`.`t1`.`a` = `test`.`t2`.`b`) and (`test`.`t2`.`filler` = (`test`.`t2`.`b` * 3)))
SELECT show_json_object('"searching_loose_scan_index": {', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"searching_loose_scan_index": {', TRACE)
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"index_handles_needed_semijoin_equalities": false
}
] /* indexes */
}
# Equality-propagation involving outer field => 3rd sj equality is bound.
explain select * from t2 as t3, t2
where t2.filler=t3.filler and
(t2.b,t2.a,t2.filler) in (select a,b,a*3 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t3 NULL ALL NULL NULL NULL NULL 100 100.00 NULL
1 SIMPLE t1 NULL index a a 10 NULL 100 100.00 Using where; Using index; LooseScan
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 1.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t3`.`filler` AS `filler`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` `t3` join `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t1`.`a`) and (`test`.`t2`.`filler` = `test`.`t3`.`filler`) and (`test`.`t3`.`filler` = (`test`.`t1`.`a` * 3)))
SELECT show_json_object('"recalculate_access_paths_and_cost": {', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"recalculate_access_paths_and_cost": {', TRACE)
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 1299.6,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_1": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"covering_scan": {
"cost": 1.0484,
"chosen": true
} /* covering_scan */
}
] /* indexes */
} /* searching_loose_scan_index */
}
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 16,
"resulting_rows": 100,
"cost": 100051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
}
# In plan t3-t1-t2, 3rd outer expression is dependent only on
# previous tables => 3rd sj equality is bound.
# If t1 is before t3, 3rd sj equality is not bound.
explain select * from t2 as t3 left join t2 on t2.filler+10=t3.filler+20
where (t2.b,t2.a,t3.filler+2) in (select a,b,a*3 from t1);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t3 NULL ALL NULL NULL NULL NULL 100 100.00 NULL
1 SIMPLE t1 NULL index a a 10 NULL 100 100.00 Using where; Using index; LooseScan
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 100 1.00 Using where; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t3`.`filler` AS `filler`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`filler` AS `filler` from `test`.`t2` `t3` join `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t1`.`a`) and ((`test`.`t3`.`filler` + 2) = (`test`.`t1`.`a` * 3)) and ((`test`.`t2`.`filler` + 10) = (`test`.`t3`.`filler` + 20)))
SELECT show_json_object('"considered_execution_plans": [', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"considered_execution_plans": [', TRACE)
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2` `t3`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 100,
"cost_for_plan": 12.996,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2` `t3`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 1016.5,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2` `t3`",
"`t2`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"rows": 1,
"cost": 3500,
"chosen": true
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 32,
"resulting_rows": 100,
"cost": 100097,
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 4516.5,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 6517.5,
"rows": 10000,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t2` `t3`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 1016.5,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2` `t3`",
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 16,
"resulting_rows": 100,
"cost": 100051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 1,
"rows_for_plan": 10000,
"cost_for_plan": 101067,
"semijoin_strategy_choice": [
{
"strategy": "LooseScan",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 1299.6,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_1": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"covering_scan": {
"cost": 1.0484,
"chosen": true
} /* covering_scan */
}
] /* indexes */
} /* searching_loose_scan_index */
}
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 16,
"resulting_rows": 100,
"cost": 100051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"cost": 101065,
"rows": 100,
"chosen": true
},
{
"strategy": "DuplicatesWeedout",
"cost": 102078,
"rows": 100,
"duplicate_tables_left": false,
"chosen": false
}
] /* semijoin_strategy_choice */,
"chosen": true,
"cause": "previous_plan_used_disabled_strategy"
}
] /* rest_of_plan */
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 100,
"cost_for_plan": 12.996,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`"
] /* plan_prefix */,
"table": "`t2` `t3`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 1016.5,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`",
"`t2` `t3`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"rows": 1,
"cost": 3500,
"chosen": true
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 32,
"resulting_rows": 100,
"cost": 100097,
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 4516.5,
"semijoin_strategy_choice": [
{
"strategy": "DuplicatesWeedout",
"cost": 6517.5,
"rows": 10000,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": false,
"cause": "plan_uses_disabled_strategy"
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t2`"
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"rows": 1,
"cost": 35,
"chosen": true
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 100,
"cost_for_plan": 47.996,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t2`",
"`t1`"
] /* plan_prefix */,
"table": "`t2` `t3`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 1051.5,
"semijoin_strategy_choice": [
{
"strategy": "LooseScan",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"rows": 1,
"cost": 35,
"chosen": true
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 1299.6,
"chosen": false
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_2": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"index_handles_needed_semijoin_equalities": false
}
] /* indexes */
} /* searching_loose_scan_index */
}
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 3052.5,
"rows": 10000,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": false,
"cause": "plan_uses_disabled_strategy"
}
] /* rest_of_plan */
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 100,
"cost_for_plan": 12.996,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2` `t3`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 1016,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`",
"`t2` `t3`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 16,
"resulting_rows": 100,
"cost": 100051,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 1,
"rows_for_plan": 10000,
"cost_for_plan": 101067,
"semijoin_strategy_choice": [
{
"strategy": "LooseScan",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_3": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"index_handles_needed_semijoin_equalities": false
}
] /* indexes */
} /* searching_loose_scan_index */
}
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 102078,
"rows": 100,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"pruned_by_cost": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
"`t1`"
] /* plan_prefix */,
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 1,
"rows_for_plan": 100,
"cost_for_plan": 1016,
"semijoin_strategy_choice": [
] /* semijoin_strategy_choice */,
"rest_of_plan": [
{
"plan_prefix": [
"`t1`",
"`t2`"
] /* plan_prefix */,
"table": "`t2` `t3`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 1,
"resulting_rows": 100,
"cost": 1003.5,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 10000,
"cost_for_plan": 2019.5,
"semijoin_strategy_choice": [
{
"strategy": "LooseScan",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 12.996,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_4": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"index_handles_needed_semijoin_equalities": false
}
] /* indexes */
} /* searching_loose_scan_index */
}
}
] /* tables */
} /* recalculate_access_paths_and_cost */,
"chosen": false
},
{
"strategy": "DuplicatesWeedout",
"cost": 3030.5,
"rows": 100,
"duplicate_tables_left": true,
"chosen": true
}
] /* semijoin_strategy_choice */,
"chosen": false,
"cause": "plan_uses_disabled_strategy"
}
] /* rest_of_plan */
}
] /* rest_of_plan */
},
{
"final_semijoin_strategy": "LooseScan",
"recalculate_access_paths_and_cost": {
"tables": [
{
"table": "`t1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "a",
"usable": false,
"chosen": false
},
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"resulting_rows": 100,
"cost": 1299.6,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */,
"unknown_key_5": {
"searching_loose_scan_index": {
"indexes": [
{
"index": "a",
"covering_scan": {
"cost": 1.0484,
"chosen": true
} /* covering_scan */
}
] /* indexes */
} /* searching_loose_scan_index */
}
},
{
"table": "`t2`",
"best_access_path": {
"considered_access_paths": [
{
"rows_to_scan": 100,
"filtering_effect": [
] /* filtering_effect */,
"final_filtering_effect": 1,
"access_type": "scan",
"using_join_cache": true,
"buffers_needed": 32,
"resulting_rows": 100,
"cost": 100097,
"chosen": true
}
] /* considered_access_paths */
} /* best_access_path */
}
] /* tables */
} /* recalculate_access_paths_and_cost */
}
]
drop table t0,t1,t2;
#
# Discover bound equality thanks to equality propagation
# specific of ON clause.
#
CREATE TABLE t1 (
a int(11) DEFAULT NULL,
b varchar(100) DEFAULT NULL,
c int(11) DEFAULT NULL,
KEY b_c_a (b,c,a)
) ENGINE=InnoDB, CHARSET utf8mb4;
Warnings:
Warning 1681 Integer display width is deprecated and will be removed in a future release.
Warning 1681 Integer display width is deprecated and will be removed in a future release.
explain select *
from t1 left join t1 as t2
on (t2.a= t1.a and (t2.a,t2.b) in (select a,b from t1 as t3))
where t1.a < 5;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL index NULL b_c_a 413 NULL 1 100.00 Using where; Using index
1 SIMPLE t3 NULL index b_c_a b_c_a 413 NULL 1 100.00 Using where; Using index; LooseScan
1 SIMPLE t2 NULL ref b_c_a b_c_a 403 test.t3.b 1 100.00 Using where; Using index
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`c` AS `c` from `test`.`t1` left join (`test`.`t1` `t2` semi join (`test`.`t1` `t3`)) on(((`test`.`t2`.`b` = `test`.`t3`.`b`) and (`test`.`t3`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`a` = `test`.`t1`.`a`))) where (`test`.`t1`.`a` < 5)
drop table t1;
#
# Show that loosescan planning is not dependent on order of
# creation of indexes anymore.
#
create table it(a int, b int, index a_b (a,b), index a (a))
engine=InnoDB;
insert into it values(1,1),(2,3),(4,3);
select * from it as ot
where (ot.a,ot.b) in (select it.a,it.b from it where it.b=3);
a b
2 3
4 3
select TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
from information_schema.optimizer_trace;
TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
0
drop table it;
create table it(a int, b int, index a (a),index a_b (a,b))
engine=InnoDB;
insert into it values(1,1),(2,3),(4,3);
select * from it as ot
where (ot.a,ot.b) in (select it.a,it.b from it where it.b=3);
a b
2 3
4 3
select TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
from information_schema.optimizer_trace;
TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
0
drop table it;
#
# Show that we reject LooseScan if no handled key parts
#
CREATE TABLE t1 (a INT, b INT, KEY (a)) ENGINE=INNODB;
CREATE TABLE t2 (a INT, b INT) ENGINE=INNODB;
EXPLAIN SELECT * FROM t2 AS t3, t2
WHERE t2.b=t3.b AND
(t2.b) IN (SELECT b*3 FROM t1 WHERE a=10);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t3 NULL ALL NULL NULL NULL NULL 1 100.00 NULL
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 1 100.00 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE t1 NULL ref a a 5 const 1 100.00 Using where; Start temporary; End temporary
Warnings:
Note 1003 /* select#1 */ select `test`.`t3`.`a` AS `a`,`test`.`t3`.`b` AS `b`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` `t3` join `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = 10) and (`test`.`t2`.`b` = `test`.`t3`.`b`) and (`test`.`t3`.`b` = (`test`.`t1`.`b` * 3)))
SELECT TRACE LIKE '%"some_index_part_used": false%'
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
TRACE LIKE '%"some_index_part_used": false%'
1
DROP TABLE t1,t2;
#
# Show that we detect a hole in sequence of key parts
#
CREATE TABLE ot1 (a INTEGER);
INSERT INTO ot1 VALUES (0),(1),(3),(7);
CREATE TABLE it1 (a VARCHAR(1), b INTEGER, KEY (a,b)) CHARSET utf8mb4;
INSERT INTO it1 VALUES ('a',7), ('b',7);
CREATE TABLE it2 (a VARCHAR(1), b INTEGER, KEY (a,b)) CHARSET utf8mb4;
INSERT INTO it2 VALUES ('a',7), ('b',7);
explain SELECT * FROM ot1
WHERE a IN (
SELECT it1.b
FROM it1 JOIN it2
ON it1.a = it2.a
);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE it1 NULL index a a 12 NULL 2 100.00 Using index; Start temporary
1 SIMPLE ot1 NULL ALL NULL NULL NULL NULL 4 25.00 Using where; Using join buffer (Block Nested Loop)
1 SIMPLE it2 NULL index a a 12 NULL 2 50.00 Using where; Using index; End temporary; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`ot1`.`a` AS `a` from `test`.`ot1` semi join (`test`.`it1` join `test`.`it2`) where ((`test`.`it2`.`a` = `test`.`it1`.`a`) and (`test`.`ot1`.`a` = `test`.`it1`.`b`))
SELECT TRACE LIKE '%"index_can_remove_duplicates": false%'
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
TRACE LIKE '%"index_can_remove_duplicates": false%'
1
DROP TABLE ot1, it1, it2;
#
# Show that handled keyparts cannot be on prefix
#
create table t1 (a int, b varchar(100), key a_b (a,b)) charset utf8mb4;
insert into t1 values(25,'111111'),(25,'1111112');
explain select * from t1 as t2 where t2.b in (select b from t1 where a=25);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ref a_b a_b 5 const 1 100.00 Using index; LooseScan
1 SIMPLE t2 NULL index NULL a_b 408 NULL 2 50.00 Using where; Using index; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` `t2` semi join (`test`.`t1`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = 25))
select * from t1 as t2 where t2.b in (select b from t1 where a=25);
a b
25 111111
25 1111112
alter table t1 drop key a_b, add key a_b_prefix (a,b(2));
explain select * from t1 as t2 where t2.b in (select b from t1 where a=25);
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t1 NULL ref a_b_prefix a_b_prefix 5 const 1 100.00 Start temporary
1 SIMPLE t2 NULL ALL NULL NULL NULL NULL 2 50.00 Using where; End temporary; Using join buffer (Block Nested Loop)
Warnings:
Note 1003 /* select#1 */ select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t1` `t2` semi join (`test`.`t1`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = 25))
select * from t1 as t2 where t2.b in (select b from t1 where a=25);
a b
25 111111
25 1111112
select TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
from information_schema.optimizer_trace;
TRACE LIKE '%"index_handles_needed_semijoin_equalities": false%'
1
drop table t1;
set optimizer_switch=@old_opt_switch;
set optimizer_prune_level=@old_opt_prune_level;
# Tracing of CTEs using the same tmp table: observe
# "reusing_tmp_table" and only one "creating_tmp_table".
with q(a) as (select 1 union all select 2)
select * from q, q q1 where q.a=1 and q1.a=2;
a a
1 2
select TRACE from information_schema.optimizer_trace;
TRACE
{
"steps": [
{
"join_preparation": {
"select#": 1,
"steps": [
{
"join_preparation": {
"select#": 2,
"steps": [
{
"expanded_query": "/* select#2 */ select 1 AS `1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 3,
"steps": [
{
"expanded_query": "/* select#3 */ select 2 AS `2`"
}
] /* steps */
} /* join_preparation */
},
{
"derived": {
"table": "`q`",
"select#": 2,
"materialized": true
} /* derived */
},
{
"join_preparation": {
"select#": 4,
"steps": [
{
"expanded_query": "/* select#4 */ select 1 AS `1`"
}
] /* steps */
} /* join_preparation */
},
{
"join_preparation": {
"select#": 5,
"steps": [
{
"expanded_query": "/* select#5 */ select 2 AS `2`"
}
] /* steps */
} /* join_preparation */
},
{
"derived": {
"table": "`q` `q1`",
"select#": 4,
"materialized": true,
"reusing_tmp_table": true
} /* derived */
},
{
"expanded_query": "/* select#1 */ select `q`.`a` AS `a`,`q1`.`a` AS `a` from `q` join `q` `q1` where ((`q`.`a` = 1) and (`q1`.`a` = 2))"
}
] /* steps */
} /* join_preparation */
},
{
"join_optimization": {
"select#": 1,
"steps": [
{
"join_optimization": {
"select#": 2,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 3,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 4,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"join_optimization": {
"select#": 5,
"steps": [
] /* steps */
} /* join_optimization */
},
{
"condition_processing": {
"condition": "WHERE",
"original_condition": "((`q`.`a` = 1) and (`q1`.`a` = 2))",
"steps": [
{
"transformation": "equality_propagation",
"resulting_condition": "(multiple equal(1, `q`.`a`) and multiple equal(2, `q1`.`a`))"
},
{
"transformation": "constant_propagation",
"resulting_condition": "(multiple equal(1, `q`.`a`) and multiple equal(2, `q1`.`a`))"
},
{
"transformation": "trivial_condition_removal",
"resulting_condition": "(multiple equal(1, `q`.`a`) and multiple equal(2, `q1`.`a`))"
}
] /* steps */
} /* condition_processing */
},
{
"substitute_generated_columns": {
} /* substitute_generated_columns */
},
{
"table_dependencies": [
{
"table": "`q`",
"row_may_be_null": false,
"map_bit": 0,
"depends_on_map_bits": [
] /* depends_on_map_bits */
},
{
"table": "`q` `q1`",
"row_may_be_null": false,
"map_bit": 1,
"depends_on_map_bits": [
] /* depends_on_map_bits */
}
] /* table_dependencies */
},
{
"ref_optimizer_key_uses": [
{
"table": "`q`",
"field": "a",
"equals": "1",
"null_rejecting": false
},
{
"table": "`q`",
"field": "a",
"equals": "1",
"null_rejecting": false
},
{
"table": "`q` `q1`",
"field": "a",
"equals": "2",
"null_rejecting": false
},
{
"table": "`q` `q1`",
"field": "a",
"equals": "2",
"null_rejecting": false
}
] /* ref_optimizer_key_uses */
},
{
"rows_estimation": [
{
"table": "`q`",
"table_scan": {
"rows": 2,
"cost": 2.525
} /* table_scan */
},
{
"table": "`q` `q1`",
"table_scan": {
"rows": 2,
"cost": 2.525
} /* table_scan */
}
] /* rows_estimation */
},
{
"considered_execution_plans": [
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`q`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "<auto_key0>",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "ref",
"index": "<auto_key1>",
"rows": 1,
"cost": 0.35,
"chosen": false
},
{
"access_type": "scan",
"cost": 2.725,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.35,
"rest_of_plan": [
{
"plan_prefix": [
"`q`"
] /* plan_prefix */,
"table": "`q` `q1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "<auto_key0>",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "ref",
"index": "<auto_key1>",
"rows": 1,
"cost": 0.35,
"chosen": false
},
{
"access_type": "scan",
"cost": 2.725,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.7,
"chosen": true
}
] /* rest_of_plan */
},
{
"plan_prefix": [
] /* plan_prefix */,
"table": "`q` `q1`",
"best_access_path": {
"considered_access_paths": [
{
"access_type": "ref",
"index": "<auto_key0>",
"rows": 1,
"cost": 0.35,
"chosen": true
},
{
"access_type": "ref",
"index": "<auto_key1>",
"rows": 1,
"cost": 0.35,
"chosen": false
},
{
"access_type": "scan",
"cost": 2.725,
"rows": 2,
"chosen": false,
"cause": "cost"
}
] /* considered_access_paths */
} /* best_access_path */,
"condition_filtering_pct": 100,
"rows_for_plan": 1,
"cost_for_plan": 0.35,
"pruned_by_heuristic": true
}
] /* considered_execution_plans */
},
{
"attaching_conditions_to_tables": {
"original_condition": "((`q1`.`a` = 2) and (`q`.`a` = 1))",
"attached_conditions_computation": [
] /* attached_conditions_computation */,
"attached_conditions_summary": [
{
"table": "`q`",
"attached": "(`q`.`a` = 1)"
},
{
"table": "`q` `q1`",
"attached": "(`q1`.`a` = 2)"
}
] /* attached_conditions_summary */
} /* attaching_conditions_to_tables */
},
{
"finalizing_table_conditions": [
{
"table": "`q`",
"original_table_condition": "(`q`.`a` = 1)",
"final_table_condition ": null
},
{
"table": "`q` `q1`",
"original_table_condition": "(`q1`.`a` = 2)",
"final_table_condition ": null
}
] /* finalizing_table_conditions */
},
{
"refine_plan": [
{
"table": "`q`"
},
{
"table": "`q` `q1`"
}
] /* refine_plan */
}
] /* steps */
} /* join_optimization */
},
{
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "`q`",
"in_plan_at_position": 0,
"columns": 1,
"row_length": 9,
"key_length": 8,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
} /* join_execution */
}
] /* steps */
}
# Tracing of repetitions of the recursive member
# can be silenced with repeated_subselect=off
with recursive qn(n) as
(select 1 union all select n+1 from qn where n<4)
select count(*) from qn;
count(*)
4
SELECT show_json_object('"join_execution": {', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"join_execution": {', TRACE)
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "`qn`",
"in_plan_at_position": 0,
"columns": 1,
"row_length": 9,
"key_length": 0,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
}
SET @@optimizer_trace_features="repeated_subselect=off";
with recursive qn(n) as
(select 1 union all select n+1 from qn where n<4)
select count(*) from qn;
count(*)
4
SELECT show_json_object('"join_execution": {', TRACE)
FROM INFORMATION_SCHEMA.OPTIMIZER_TRACE;
show_json_object('"join_execution": {', TRACE)
"join_execution": {
"select#": 1,
"steps": [
{
"creating_tmp_table": {
"tmp_table_info": {
"table": "`qn`",
"in_plan_at_position": 0,
"columns": 1,
"row_length": 9,
"key_length": 0,
"unique_constraint": false,
"makes_grouped_rows": false,
"cannot_insert_duplicates": false,
"location": "TempTable"
} /* tmp_table_info */
} /* creating_tmp_table */
},
{
"materialize": {
"select#": 2,
"steps": [
] /* steps */
} /* materialize */
},
{
"materialize": {
"select#": 3,
"steps": [
] /* steps */
} /* materialize */
}
] /* steps */
}
SET @@optimizer_trace_features=default;
drop function show_json_object;
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