523 lines
13 KiB
Plaintext
523 lines
13 KiB
Plaintext
#
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# Bug#20443863 USE OF WORST_SEEKS IN FIND_BEST_REF() CAN LEAD TO
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# WRONG QUERY PLAN
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#
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CREATE TABLE t1 (
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i1 INTEGER,
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i2 INTEGER,
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i3 INTEGER,
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KEY(i1,i2)
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) ENGINE=XENGINE;
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INSERT INTO t1 VALUES (1, 1, 1), (1, 1, 1),(1, 1, 1),(1, 1, 1),
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(2, 2, 1), (2, 2, 1),(2, 2, 1),(2, 2, 1),
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(3, 3, 1), (3, 3, 1),(3, 3, 1),(3, 3, 1);
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EXPLAIN FORMAT=JSON SELECT i3 FROM t1 WHERE i1 = 1 AND i2 = 1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "0.35"
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},
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"table": {
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"table_name": "t1",
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"access_type": "ref",
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"possible_keys": [
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"i1"
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],
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"key": "i1",
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"used_key_parts": [
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"i1",
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"i2"
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],
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"key_length": "10",
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"ref": [
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"const",
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"const"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 1,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "0.25",
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"eval_cost": "0.10",
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"prefix_cost": "0.35",
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"data_read_per_join": "16"
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},
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"used_columns": [
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"i1",
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"i2",
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"i3"
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]
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`i3` AS `i3` from `test`.`t1` where ((`test`.`t1`.`i2` = 1) and (`test`.`t1`.`i1` = 1))
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EXPLAIN FORMAT=JSON SELECT i3 FROM t1 WHERE i1 = 1 AND i3 = 1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "0.35"
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},
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"table": {
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"table_name": "t1",
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"access_type": "ref",
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"possible_keys": [
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"i1"
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],
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"key": "i1",
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"used_key_parts": [
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"i1"
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],
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"key_length": "5",
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"ref": [
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"const"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 0,
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"filtered": "10.00",
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"cost_info": {
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"read_cost": "0.25",
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"eval_cost": "0.01",
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"prefix_cost": "0.35",
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"data_read_per_join": "1"
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},
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"used_columns": [
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"i1",
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"i3"
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],
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"attached_condition": "(`test`.`t1`.`i3` = 1)"
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`i3` AS `i3` from `test`.`t1` where ((`test`.`t1`.`i3` = 1) and (`test`.`t1`.`i1` = 1))
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UPDATE mysql.server_cost
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SET cost_value=0.1
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WHERE cost_name="row_evaluate_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.05
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WHERE cost_name="key_compare_cost";
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UPDATE mysql.server_cost
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SET cost_value=1.0
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WHERE cost_name="memory_temptable_create_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.1
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WHERE cost_name="memory_temptable_row_cost";
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UPDATE mysql.server_cost
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SET cost_value=20
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WHERE cost_name="disk_temptable_create_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.5
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WHERE cost_name="disk_temptable_row_cost";
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UPDATE mysql.engine_cost
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SET cost_value=0.25
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WHERE cost_name="memory_block_read_cost";
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UPDATE mysql.engine_cost
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SET cost_value=1.0
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WHERE cost_name="io_block_read_cost";
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UPDATE mysql.server_cost
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SET cost_value = 2 * cost_value;
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UPDATE mysql.engine_cost
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SET cost_value = 2 * cost_value;
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SELECT cost_name, cost_value FROM mysql.server_cost;
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cost_name cost_value
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disk_temptable_create_cost 40
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disk_temptable_row_cost 1
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key_compare_cost 0.1
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memory_temptable_create_cost 2
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memory_temptable_row_cost 0.2
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row_evaluate_cost 0.2
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SELECT cost_name, cost_value FROM mysql.engine_cost;
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cost_name cost_value
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io_block_read_cost 2
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memory_block_read_cost 0.5
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FLUSH OPTIMIZER_COSTS;
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EXPLAIN FORMAT=JSON SELECT i3 FROM t1 WHERE i1 = 1 AND i2 = 1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "0.70"
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},
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"table": {
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"table_name": "t1",
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"access_type": "ref",
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"possible_keys": [
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"i1"
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],
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"key": "i1",
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"used_key_parts": [
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"i1",
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"i2"
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],
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"key_length": "10",
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"ref": [
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"const",
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"const"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 1,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "0.50",
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"eval_cost": "0.20",
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"prefix_cost": "0.70",
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"data_read_per_join": "16"
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},
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"used_columns": [
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"i1",
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"i2",
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"i3"
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]
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`i3` AS `i3` from `test`.`t1` where ((`test`.`t1`.`i2` = 1) and (`test`.`t1`.`i1` = 1))
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EXPLAIN FORMAT=JSON SELECT i3 FROM t1 WHERE i1 = 1 AND i3 = 1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "0.70"
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},
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"table": {
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"table_name": "t1",
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"access_type": "ref",
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"possible_keys": [
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"i1"
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],
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"key": "i1",
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"used_key_parts": [
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"i1"
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],
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"key_length": "5",
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"ref": [
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"const"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 0,
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"filtered": "10.00",
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"cost_info": {
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"read_cost": "0.50",
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"eval_cost": "0.02",
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"prefix_cost": "0.70",
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"data_read_per_join": "1"
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},
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"used_columns": [
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"i1",
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"i3"
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],
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"attached_condition": "(`test`.`t1`.`i3` = 1)"
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`i3` AS `i3` from `test`.`t1` where ((`test`.`t1`.`i3` = 1) and (`test`.`t1`.`i1` = 1))
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UPDATE mysql.server_cost
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SET cost_value=DEFAULT;
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UPDATE mysql.engine_cost
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SET cost_value=DEFAULT;
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FLUSH OPTIMIZER_COSTS;
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DROP TABLE t1;
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#
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# Bug#20947871 INDEX SCAN COST IN TEST_IF_CHEAPER_ORDERING() DOES
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# NOT USE COST CONSTANTS
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#
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CREATE TABLE t1 (
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pk INTEGER PRIMARY KEY,
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a INTEGER,
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b INTEGER,
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c CHAR(255),
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UNIQUE KEY k1 (a)
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);
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INSERT INTO t1 VALUES (1, 1, NULL, "Abc"), (2, 2, NULL, "Abc"),
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(3, 3, NULL, "Abc"), (4, 4, NULL, "Abc");
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INSERT INTO t1 SELECT a + 4, a + 4, b, c FROM t1;
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INSERT INTO t1 SELECT a + 8, a + 8, b, c FROM t1;
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INSERT INTO t1 SELECT a + 16, a + 16, b, c FROM t1;
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INSERT INTO t1 SELECT a + 32, a + 32, b, c FROM t1;
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INSERT INTO t1 SELECT a + 64, a + 64, b, c FROM t1;
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INSERT INTO t1 SELECT a + 128, a + 128, b, c FROM t1;
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CREATE TABLE t2 (
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d INTEGER PRIMARY KEY,
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e INTEGER
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);
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INSERT INTO t2 SELECT a, b FROM t1;
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# Query should be optimized for the LIMIT. Query plan should
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# use index without filesort
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EXPLAIN FORMAT=JSON SELECT * FROM t1 JOIN t2 ON b=d ORDER BY a LIMIT 4;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "120.90"
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},
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"ordering_operation": {
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"using_filesort": false,
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"nested_loop": [
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{
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"table": {
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"table_name": "t1",
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"access_type": "index",
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"key": "k1",
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"used_key_parts": [
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"a"
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],
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"key_length": "5",
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"rows_examined_per_scan": 4,
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"rows_produced_per_join": 256,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "5.70",
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"eval_cost": "25.60",
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"prefix_cost": "31.30",
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"data_read_per_join": "260K"
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},
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"used_columns": [
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"pk",
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"a",
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"b",
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"c"
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],
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"attached_condition": "(`test`.`t1`.`b` is not null)"
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}
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},
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{
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"table": {
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"table_name": "t2",
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"access_type": "eq_ref",
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"possible_keys": [
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"PRIMARY"
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],
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"key": "PRIMARY",
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"used_key_parts": [
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"d"
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],
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"key_length": "4",
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"ref": [
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"test.t1.b"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 256,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "64.00",
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"eval_cost": "25.60",
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"prefix_cost": "120.90",
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"data_read_per_join": "4K"
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},
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"used_columns": [
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"d",
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"e"
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]
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}
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}
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]
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c`,`test`.`t2`.`d` AS `d`,`test`.`t2`.`e` AS `e` from `test`.`t1` join `test`.`t2` where (`test`.`t2`.`d` = `test`.`t1`.`b`) order by `test`.`t1`.`a` limit 4
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UPDATE mysql.server_cost
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SET cost_value=0.1
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WHERE cost_name="row_evaluate_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.05
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WHERE cost_name="key_compare_cost";
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UPDATE mysql.server_cost
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SET cost_value=1.0
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WHERE cost_name="memory_temptable_create_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.1
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WHERE cost_name="memory_temptable_row_cost";
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UPDATE mysql.server_cost
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SET cost_value=20
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WHERE cost_name="disk_temptable_create_cost";
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UPDATE mysql.server_cost
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SET cost_value=0.5
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WHERE cost_name="disk_temptable_row_cost";
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UPDATE mysql.engine_cost
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SET cost_value=0.25
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WHERE cost_name="memory_block_read_cost";
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UPDATE mysql.engine_cost
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SET cost_value=1.0
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WHERE cost_name="io_block_read_cost";
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UPDATE mysql.server_cost
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SET cost_value = 0.5 * cost_value;
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UPDATE mysql.engine_cost
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SET cost_value = 0.5 * cost_value;
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SELECT cost_name, cost_value FROM mysql.server_cost;
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cost_name cost_value
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disk_temptable_create_cost 10
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disk_temptable_row_cost 0.25
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key_compare_cost 0.025
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memory_temptable_create_cost 0.5
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memory_temptable_row_cost 0.05
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row_evaluate_cost 0.05
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SELECT cost_name, cost_value FROM mysql.engine_cost;
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cost_name cost_value
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io_block_read_cost 0.5
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memory_block_read_cost 0.125
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FLUSH OPTIMIZER_COSTS;
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# This should be optimized for the LIMIT. Query plan should
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# use index without filesort
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EXPLAIN FORMAT=JSON SELECT * FROM t1 JOIN t2 ON b=d ORDER BY a LIMIT 4;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "60.45"
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},
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"ordering_operation": {
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"using_filesort": false,
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"nested_loop": [
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{
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"table": {
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"table_name": "t1",
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"access_type": "index",
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"key": "k1",
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"used_key_parts": [
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"a"
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],
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"key_length": "5",
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"rows_examined_per_scan": 4,
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"rows_produced_per_join": 256,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "2.85",
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"eval_cost": "12.80",
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"prefix_cost": "15.65",
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"data_read_per_join": "260K"
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},
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"used_columns": [
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"pk",
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"a",
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"b",
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"c"
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],
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"attached_condition": "(`test`.`t1`.`b` is not null)"
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}
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},
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{
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"table": {
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"table_name": "t2",
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"access_type": "eq_ref",
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"possible_keys": [
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"PRIMARY"
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],
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"key": "PRIMARY",
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"used_key_parts": [
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"d"
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],
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"key_length": "4",
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"ref": [
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"test.t1.b"
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],
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"rows_examined_per_scan": 1,
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"rows_produced_per_join": 256,
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"filtered": "100.00",
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"cost_info": {
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"read_cost": "32.00",
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"eval_cost": "12.80",
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"prefix_cost": "60.45",
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"data_read_per_join": "4K"
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},
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"used_columns": [
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"d",
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"e"
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]
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}
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}
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]
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}
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}
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}
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Warnings:
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Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t1`.`c` AS `c`,`test`.`t2`.`d` AS `d`,`test`.`t2`.`e` AS `e` from `test`.`t1` join `test`.`t2` where (`test`.`t2`.`d` = `test`.`t1`.`b`) order by `test`.`t1`.`a` limit 4
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UPDATE mysql.server_cost
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SET cost_value=DEFAULT;
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UPDATE mysql.engine_cost
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SET cost_value=DEFAULT;
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FLUSH OPTIMIZER_COSTS;
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DROP TABLE t1, t2;
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#
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# Bug#23508576 FILL_INDEXES_FROM_DD() DOES NOT INITIALIZE
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# ST_KEY::M_IN_MEMORY_ESTIMATE
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#
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UPDATE mysql.engine_cost
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SET cost_value=0.5
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WHERE cost_name="memory_block_read_cost";
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UPDATE mysql.engine_cost
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SET cost_value=2
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WHERE cost_name="io_block_read_cost";
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FLUSH OPTIMIZER_COSTS;
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SELECT engine_name, device_type, cost_name, cost_value
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FROM mysql.engine_cost
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WHERE cost_name="memory_block_read_cost"
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OR cost_name="io_block_read_cost";
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engine_name device_type cost_name cost_value
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default 0 io_block_read_cost 2
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default 0 memory_block_read_cost 0.5
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CREATE TABLE t1 (
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i1 INTEGER,
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c1 CHAR(200),
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INDEX idx (i1)
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) ENGINE=MyISAM;
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INSERT INTO t1 VALUES (1, "Ullensvang"), (2, "Odda"), (3, "Jondal");
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# Pass criteria for the query plan:
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# 1. Should be executed as an index-only range scan
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# 2. Cost estimate: "read_cost" - "eval_cost" should be approximately
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# the cost of reading one page from memory, ie. about 0.5.
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EXPLAIN FORMAT=JSON
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SELECT i1 FROM t1 WHERE i1 > 1;
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EXPLAIN
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{
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"query_block": {
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"select_id": 1,
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"cost_info": {
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"query_cost": "0.92"
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},
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"table": {
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"table_name": "t1",
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"access_type": "range",
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"possible_keys": [
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"idx"
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],
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"key": "idx",
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"used_key_parts": [
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"i1"
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],
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"key_length": "5",
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"rows_examined_per_scan": 2,
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"rows_produced_per_join": 2,
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"filtered": "100.00",
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"using_index": true,
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|
"cost_info": {
|
|
"read_cost": "0.72",
|
|
"eval_cost": "0.20",
|
|
"prefix_cost": "0.92",
|
|
"data_read_per_join": "1K"
|
|
},
|
|
"used_columns": [
|
|
"i1"
|
|
],
|
|
"attached_condition": "(`test`.`t1`.`i1` > 1)"
|
|
}
|
|
}
|
|
}
|
|
Warnings:
|
|
Note 1003 /* select#1 */ select `test`.`t1`.`i1` AS `i1` from `test`.`t1` where (`test`.`t1`.`i1` > 1)
|
|
DROP TABLE t1;
|
|
UPDATE mysql.engine_cost
|
|
SET cost_value=DEFAULT;
|
|
FLUSH OPTIMIZER_COSTS;
|