| Server IP : 104.21.38.3 / Your IP : 162.158.108.158 Web Server : Apache System : Linux krdc-ubuntu-s-2vcpu-4gb-amd-blr1-01.localdomain 5.15.0-142-generic #152-Ubuntu SMP Mon May 19 10:54:31 UTC 2025 x86_64 User : www ( 1000) PHP Version : 7.4.33 Disable Function : passthru,exec,system,putenv,chroot,chgrp,chown,shell_exec,popen,proc_open,pcntl_exec,ini_alter,ini_restore,dl,openlog,syslog,readlink,symlink,popepassthru,pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wifcontinued,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,imap_open,apache_setenv MySQL : OFF | cURL : ON | WGET : ON | Perl : ON | Python : OFF | Sudo : ON | Pkexec : ON Directory : /www/server/mysql/src/mysql-test/r/ |
Upload File : |
SELECT * FROM mysql.server_cost;
cost_name cost_value last_update comment
disk_temptable_create_cost NULL # NULL
disk_temptable_row_cost NULL # NULL
key_compare_cost NULL # NULL
memory_temptable_create_cost NULL # NULL
memory_temptable_row_cost NULL # NULL
row_evaluate_cost NULL # NULL
SHOW INDEX FROM mysql.server_cost;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
server_cost 0 PRIMARY 1 cost_name A # NULL NULL BTREE
SELECT * FROM mysql.engine_cost;
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost NULL # NULL
default 0 memory_block_read_cost NULL # NULL
SHOW INDEX FROM mysql.engine_cost;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
engine_cost 0 PRIMARY 1 cost_name A # NULL NULL BTREE
engine_cost 0 PRIMARY 2 engine_name A # NULL NULL BTREE
engine_cost 0 PRIMARY 3 device_type A # NULL NULL BTREE
UPDATE mysql.server_cost
SET cost_value=0.1
WHERE cost_name="row_evaluate_cost";
SELECT *
FROM mysql.server_cost
WHERE cost_name="row_evaluate_cost";
cost_name cost_value last_update comment
row_evaluate_cost 0.1 # NULL
UPDATE mysql.server_cost
SET cost_value=DEFAULT
WHERE cost_name="row_evaluate_cost";
SELECT *
FROM mysql.server_cost
WHERE cost_name="row_evaluate_cost";
cost_name cost_value last_update comment
row_evaluate_cost NULL # NULL
INSERT INTO mysql.server_cost
VALUES ("lunch_cost", DEFAULT, CURRENT_TIMESTAMP, "Lunch is important");
SELECT * FROM mysql.server_cost;
cost_name cost_value last_update comment
disk_temptable_create_cost NULL # NULL
disk_temptable_row_cost NULL # NULL
key_compare_cost NULL # NULL
lunch_cost NULL # Lunch is important
memory_temptable_create_cost NULL # NULL
memory_temptable_row_cost NULL # NULL
row_evaluate_cost NULL # NULL
DELETE FROM mysql.server_cost
WHERE cost_name="lunch_cost";
INSERT INTO mysql.server_cost
VALUES ("row_evaluate_cost", DEFAULT, CURRENT_TIMESTAMP, "Faster CPU");
ERROR 23000: Duplicate entry 'row_evaluate_cost' for key 'PRIMARY'
INSERT INTO mysql.server_cost
VALUES ("ROW_EVALUATE_COST", DEFAULT, CURRENT_TIMESTAMP, "Faster CPU");
ERROR 23000: Duplicate entry 'ROW_EVALUATE_COST' for key 'PRIMARY'
SELECT * FROM mysql.server_cost;
cost_name cost_value last_update comment
disk_temptable_create_cost NULL # NULL
disk_temptable_row_cost NULL # NULL
key_compare_cost NULL # NULL
memory_temptable_create_cost NULL # NULL
memory_temptable_row_cost NULL # NULL
row_evaluate_cost NULL # NULL
UPDATE mysql.engine_cost
SET cost_value=0.1
WHERE cost_name="io_block_read_cost";
SELECT *
FROM mysql.engine_cost
WHERE cost_name="io_block_read_cost";
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost 0.1 # NULL
UPDATE mysql.engine_cost
SET cost_value=DEFAULT
WHERE cost_name="io_block_read_cost";
SELECT *
FROM mysql.engine_cost
WHERE cost_name="io_block_read_cost";
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost NULL # NULL
INSERT INTO mysql.engine_cost
VALUES ("InnoDB", 2, "lunch_cost1", DEFAULT, CURRENT_TIMESTAMP, "Lunch 1"),
("InnoDB", 2, "lunch_cost2", DEFAULT, CURRENT_TIMESTAMP, "Lunch 2");
SELECT * FROM mysql.engine_cost;
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost NULL # NULL
InnoDB 2 lunch_cost1 NULL # Lunch 1
InnoDB 2 lunch_cost2 NULL # Lunch 2
default 0 memory_block_read_cost NULL # NULL
DELETE FROM mysql.engine_cost
WHERE cost_name LIKE "lunch_cost%";
INSERT INTO mysql.engine_cost
VALUES ("default", 0, "lunch_cost", DEFAULT, CURRENT_TIMESTAMP, "Lunch");
INSERT INTO mysql.engine_cost
VALUES ("default", 0, "lunch_cost", DEFAULT, CURRENT_TIMESTAMP, "Lunch");
ERROR 23000: Duplicate entry 'lunch_cost-default-0' for key 'PRIMARY'
SELECT * FROM mysql.engine_cost;
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost NULL # NULL
default 0 lunch_cost NULL # Lunch
default 0 memory_block_read_cost NULL # NULL
DELETE FROM mysql.engine_cost
WHERE cost_name="lunch_cost";
INSERT INTO mysql.engine_cost
VALUES ("default", 0, "IO_BLOCK_READ_COST", DEFAULT, CURRENT_TIMESTAMP,
"Lunch");
ERROR 23000: Duplicate entry 'IO_BLOCK_READ_COST-default-0' for key 'PRIMARY'
SELECT * FROM mysql.engine_cost;
engine_name device_type cost_name cost_value last_update comment
default 0 io_block_read_cost NULL # NULL
default 0 memory_block_read_cost NULL # NULL
CREATE TABLE server_cost_tmp (
cost_name VARCHAR(64) NOT NULL,
last_update TIMESTAMP
);
CREATE TABLE engine_cost_tmp (
cost_name VARCHAR(64) NOT NULL,
last_update TIMESTAMP
);
INSERT INTO server_cost_tmp
SELECT cost_name, last_update FROM mysql.server_cost;
INSERT INTO engine_cost_tmp
SELECT cost_name, last_update FROM mysql.engine_cost;
UPDATE mysql.server_cost
SET cost_value=0.1
WHERE cost_name="row_evaluate_cost";
SELECT mysql.server_cost.cost_name
FROM mysql.server_cost JOIN server_cost_tmp
ON mysql.server_cost.cost_name = server_cost_tmp.cost_name
WHERE mysql.server_cost.last_update > server_cost_tmp.last_update;
cost_name
row_evaluate_cost
UPDATE mysql.server_cost
SET cost_value=DEFAULT
WHERE cost_name="row_evaluate_cost";
UPDATE mysql.engine_cost
SET cost_value=2.0
WHERE cost_name="io_block_read_cost";
SELECT mysql.engine_cost.cost_name
FROM mysql.engine_cost JOIN engine_cost_tmp
ON mysql.engine_cost.cost_name = engine_cost_tmp.cost_name
WHERE mysql.engine_cost.last_update > engine_cost_tmp.last_update;
cost_name
io_block_read_cost
UPDATE mysql.engine_cost
SET cost_value=DEFAULT
WHERE cost_name="io_block_read_cost";
DROP TABLE server_cost_tmp, engine_cost_tmp;