MySQL 状态变量(Server Status Variables)(二)

--从information_schema.global_status表查询状态变量OPENED_TABLES
root@localhost[tempdb]> select * from information_schema.global_status
-> where variable_name like 'opened_tables';
+---------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+---------------+----------------+
| OPENED_TABLES | 55 |
+---------------+----------------+

--清洗状态变量统计信息
root@localhost[tempdb]> flush status;
Query OK, 0 rows affected (0.00 sec)

--下面的查询结果可以看出，session级别的opened_tables被重置为0
root@localhost[tempdb]> show session status like 'opened_tables';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Opened_tables | 0 |
+---------------+-------+

--Author: Leshami
--Blog : http://blog.csdn.net/leshami

--而全局级别的opened_tables未受到任何影响
root@localhost[tempdb]> show global status like 'opened_tables';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Opened_tables | 55 |
+---------------+-------+

3、使用mysqladmin extended-status获取状态变量

suse11b:~ # mysqladmin extended-status|grep Connections
| Connections | 18 |
suse11b:~ # mysql

root@localhost[(none)]> system mysqladmin extended-status|grep Connections
| Connections | 20 |
root@localhost[(none)]> exit
Bye
suse11b:~ # mysqladmin --help |more #mysqladmin与状态变量有关的使用
extended-status Gives an extended status message from the server
flush-status Clear status variables

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