| Current Path : /home/usr.opt/mysql57/mysql-test/r/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //home/usr.opt/mysql57/mysql-test/r/opt_costmodel_flush.result |
CREATE TABLE t0 (
i1 INTEGER
);
INSERT INTO t0 VALUE (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
CREATE TABLE t1 (
pk INTEGER PRIMARY KEY,
i1 INTEGER NOT NULL,
c1 CHAR(250),
c2 CHAR(250),
c3 CHAR(250),
c4 CHAR(250),
INDEX i1_key (i1)
) ENGINE=InnoDB;
INSERT INTO t1
SELECT a0.i1 + 10 * a1.i1, a0.i1, 'abc', 'def', 'ghi', 'jkl'
FROM t0 AS a0, t0 AS a1;
ANALYZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 analyze status OK
EXPLAIN FORMAT=JSON SELECT * FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "29.00"
},
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
]
}
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1`
#
# Test that updating the cost constants does not influence on an
# existing connection
#
UPDATE mysql.server_cost
SET cost_value=0.4
WHERE cost_name="row_evaluate_cost";
FLUSH OPTIMIZER_COSTS;
#
# The cost estimates should not have changed
#
EXPLAIN FORMAT=JSON SELECT * FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "29.00"
},
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
]
}
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1`
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
#
# Test effect of changing the row_evalute_cost
#
UPDATE mysql.server_cost
SET cost_value=0.4
WHERE cost_name="row_evaluate_cost";
FLUSH OPTIMIZER_COSTS;
#
# Verify that the cost estimate for evalution cost has doubled
#
EXPLAIN FORMAT=JSON SELECT * FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "49.00"
},
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "40.00",
"prefix_cost": "49.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
]
}
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1`
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
#
# Test effect of changing key_compare_cost
#
# Use a query that will use loose index scan since loose index scan
# is comparing keys in order to determine group boundaries.
# Result from running query with default cost constants:
#
EXPLAIN FORMAT=JSON SELECT DISTINCT(i1) FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "6.50"
},
"duplicates_removal": {
"using_filesort": false,
"table": {
"table_name": "t1",
"access_type": "range",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 11,
"rows_produced_per_join": 11,
"filtered": "100.00",
"using_index_for_group_by": true,
"cost_info": {
"read_cost": "4.30",
"eval_cost": "2.20",
"prefix_cost": "6.50",
"data_read_per_join": "10K"
},
"used_columns": [
"pk",
"i1"
]
}
}
}
}
Warnings:
Note 1003 /* select#1 */ select distinct `test`.`t1`.`i1` AS `i1` from `test`.`t1`
UPDATE mysql.server_cost
SET cost_value=0.2
WHERE cost_name="key_compare_cost";
FLUSH OPTIMIZER_COSTS;
#
# Verify that the cost estimate for read cost is increased
#
EXPLAIN FORMAT=JSON SELECT DISTINCT(i1) FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "7.60"
},
"duplicates_removal": {
"using_filesort": false,
"table": {
"table_name": "t1",
"access_type": "range",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 11,
"rows_produced_per_join": 11,
"filtered": "100.00",
"using_index_for_group_by": true,
"cost_info": {
"read_cost": "5.40",
"eval_cost": "2.20",
"prefix_cost": "7.60",
"data_read_per_join": "10K"
},
"used_columns": [
"pk",
"i1"
]
}
}
}
}
Warnings:
Note 1003 /* select#1 */ select distinct `test`.`t1`.`i1` AS `i1` from `test`.`t1`
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
#
# Test effect of changing memory_temptable_create_cost
#
# Use a query that creates a temporary table for a subquery.
# Run query with default cost constants.
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE i1 IN (SELECT i1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "100.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"possible_keys": [
"i1_key"
],
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`i1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "4",
"ref": [
"test.t1.i1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "index",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"using_index": true,
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"i1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`i1` = `test`.`t1`.`i1`)
UPDATE mysql.server_cost
SET cost_value=10.0
WHERE cost_name="memory_temptable_create_cost";
FLUSH OPTIMIZER_COSTS;
#
# Verify that the cost estimate for the query is incrased (by 8.0)
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE i1 IN (SELECT i1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "108.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"possible_keys": [
"i1_key"
],
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`i1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "4",
"ref": [
"test.t1.i1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "index",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"using_index": true,
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"i1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`i1` = `test`.`t1`.`i1`)
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
#
# Test effect of changing memory_temptable_row_cost
#
# Use a query that creates a temporary table for a subquery.
# Result from running query with default cost constants:
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE i1 IN (SELECT i1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "100.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"possible_keys": [
"i1_key"
],
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`i1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "4",
"ref": [
"test.t1.i1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "index",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"using_index": true,
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"i1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`i1` = `test`.`t1`.`i1`)
UPDATE mysql.server_cost
SET cost_value=0.4
WHERE cost_name="memory_temptable_row_cost";
FLUSH OPTIMIZER_COSTS;
#
# Verify that the cost estimate for the query is incrased by:
# 100 rows that needs to be inserted and read from the temporary table.
# The cost of each insert and read is increased by 0.2, ie cost should
# be increased by 100 * 2 * 0.2 = 40.
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE i1 IN (SELECT i1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "140.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"possible_keys": [
"i1_key"
],
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`i1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "4",
"ref": [
"test.t1.i1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "index",
"possible_keys": [
"i1_key"
],
"key": "i1_key",
"used_key_parts": [
"i1"
],
"key_length": "4",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"using_index": true,
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"i1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`i1` = `test`.`t1`.`i1`)
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
set @max_heap_table_size_save= @@max_heap_table_size;
set max_heap_table_size= 16384;
#
# Test effect of changing disk_temptable_create_cost
#
# Use a query that creates a temporary table for a subquery.
# Result from running query with default cost constants:
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE c1 IN (SELECT c1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "298.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`c1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "251",
"ref": [
"test.t1.c1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"c1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`c1` = `test`.`t1`.`c1`)
UPDATE mysql.server_cost
SET cost_value=80.0
WHERE cost_name="disk_temptable_create_cost";
FLUSH OPTIMIZER_COSTS;
set max_heap_table_size= 16384;
#
# Verify that the cost estimate for the query is incrased (by 40.0)
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE c1 IN (SELECT c1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "338.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`c1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "251",
"ref": [
"test.t1.c1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"c1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`c1` = `test`.`t1`.`c1`)
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
#
# Test effect of changing disk_temptable_row_cost
#
# Use a query that creates a temporary table for a subquery
# Result from running query with default cost constants:
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE c1 IN (SELECT c1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "298.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`c1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "251",
"ref": [
"test.t1.c1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"c1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`c1` = `test`.`t1`.`c1`)
UPDATE mysql.server_cost
SET cost_value=2.0
WHERE cost_name="disk_temptable_row_cost";
FLUSH OPTIMIZER_COSTS;
set max_heap_table_size= 16384;
#
# Verify that the cost estimate for the query is incrased by:
# 100 rows that needs to be inserted and read from the temporary table.
# The cost of each insert and read is increased by 1.0, ie cost should
# be increased by 100 * 2 * 1.0 = 200.
#
EXPLAIN FORMAT=JSON SELECT * FROM t1
WHERE c1 IN (SELECT c1 FROM t1);
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "498.00"
},
"nested_loop": [
{
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
],
"attached_condition": "(`test`.`t1`.`c1` is not null)"
}
},
{
"table": {
"table_name": "<subquery2>",
"access_type": "eq_ref",
"key": "<auto_key>",
"key_length": "251",
"ref": [
"test.t1.c1"
],
"rows_examined_per_scan": 1,
"materialized_from_subquery": {
"using_temporary_table": true,
"query_block": {
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"c1"
]
}
}
}
}
}
]
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1` semi join (`test`.`t1`) where (`<subquery2>`.`c1` = `test`.`t1`.`c1`)
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
set max_heap_table_size= @max_heap_table_size_save;
#
# Test effect of changing the memory_block_read_cost
#
# Result from running query with default cost constants:
#
EXPLAIN FORMAT=JSON SELECT * FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "29.00"
},
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "9.00",
"eval_cost": "20.00",
"prefix_cost": "29.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
]
}
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1`
UPDATE mysql.engine_cost
SET cost_value=2.0
WHERE cost_name="memory_block_read_cost";
FLUSH OPTIMIZER_COSTS;
#
# Verify that the cost estimate for read cost has doubled
#
EXPLAIN FORMAT=JSON SELECT * FROM t1;
EXPLAIN
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "38.00"
},
"table": {
"table_name": "t1",
"access_type": "ALL",
"rows_examined_per_scan": 100,
"rows_produced_per_join": 100,
"filtered": "100.00",
"cost_info": {
"read_cost": "18.00",
"eval_cost": "20.00",
"prefix_cost": "38.00",
"data_read_per_join": "99K"
},
"used_columns": [
"pk",
"i1",
"c1",
"c2",
"c3",
"c4"
]
}
}
}
Warnings:
Note 1003 /* select#1 */ select `test`.`t1`.`pk` AS `pk`,`test`.`t1`.`i1` AS `i1`,`test`.`t1`.`c1` AS `c1`,`test`.`t1`.`c2` AS `c2`,`test`.`t1`.`c3` AS `c3`,`test`.`t1`.`c4` AS `c4` from `test`.`t1`
UPDATE mysql.engine_cost
SET cost_value=DEFAULT;
FLUSH OPTIMIZER_COSTS;
DROP TABLE t0,t1;