SHOW STATUS提供MySQL服务的状态信息，执行这个语句只需要连接到MySQL数据库的权限。
这些服务状态信息来源于以下:
① 性能用户的表。

② INFORMATION_SCHEMA用户下的GLOBAL_STATUS和SESSION_STATUS表。

MariaDB [test]> desc information_schema.global_status;
+----------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------+---------------+------+-----+---------+-------+
| VARIABLE_NAME | varchar(64)| NO| | ||
| VARIABLE_VALUE | varchar(2048) | NO| | ||
+----------------+---------------+------+-----+---------+-------+
2 rows in set (0.12 sec)

MariaDB [test]> select * from information_schema.global_status where variable_name like 'Com_insert%';
+-------------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+-------------------+----------------+
| COM_INSERT| 106|
| COM_INSERT_SELECT | 10 |
+-------------------+----------------+
2 rows in set (0.00 sec)

MariaDB [test]> desc information_schema.session_status;
+----------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------------+---------------+------+-----+---------+-------+
| VARIABLE_NAME | varchar(64)| NO| | ||
| VARIABLE_VALUE | varchar(2048) | NO| | ||
+----------------+---------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

MariaDB [test]> select * from information_schema.session_status where variable_name like 'Com_insert%';
+-------------------+----------------+
| VARIABLE_NAME | VARIABLE_VALUE |
+-------------------+----------------+
| COM_INSERT| 19 |
| COM_INSERT_SELECT | 0 |
+-------------------+----------------+
2 rows in set (0.00 sec)

③ mysqladmin的extended-status命令
[root@localhost 20160630]# /maria/bin/mysqladmin -uroot -p extended-status|grep Com|more
Enter password:
| Com_admin_commands| 0 |
| Com_alter_db | 0 |
| Com_alter_db_upgrade | 0 |
| Com_alter_event | 0 |
| Com_alter_function| 0 |
| Com_alter_procedure | 0 |
| Com_alter_server | 0 |
| Com_alter_table | 40 |
| Com_alter_tablespace | 0 |
| Com_analyze | 3 |
| Com_assign_to_keycache| 0 |
| Com_begin| 0 |
| Com_binlog| 0 |
| Com_call_procedure| 3 |
| Com_change_db| 43 |
| Com_change_master| 0 |
| Com_check| 0 |
| Com_checksum | 0 |
| Com_commit| 0 |
| Com_compound_sql | 0 |
| Com_create_db| 1 |
| Com_create_event | 0 |
| Com_create_function | 0 |
| Com_create_index | 4 |
| Com_create_procedure | 4 |

SHOW STATUS接受GLOBAL或SESSION参数，分别显示全局或当前连接会话信息，如果不带参数则显示的是当前会话的信息。

每次调用SHOW STATUS语句会使用一个临时表，并会增加Created_tmp_tables全局参数的值。
MariaDB [test]> show global status like 'Created_tmp_tables';
+--------------------+-------+
| Variable_name | Value |
+--------------------+-------+
| Created_tmp_tables | 894|
+--------------------+-------+
1 row in set (0.00 sec)

MariaDB [test]> show global status like 'Created_tmp_tables';
+--------------------+-------+
| Variable_name | Value |
+--------------------+-------+
| Created_tmp_tables | 895|
+--------------------+-------+
1 row in set (0.00 sec)

--常用的统计参数

Com_select执行SELECT操作的次数
Com_insert执行INSERT操作的次数
Com_update执行UPDATE操作的次数
Com_delete执行DELETE操作的次数

Innodb_rows_readInnoDB存储引擎SELECT查询返回的行数
Innodb_rows_insertedInnoDB存储引擎执行INSERT操作插入的行数
Innodb_rows_updatedInnoDB存储引擎执行UPDATE操作更新的行数
Innodb_rows_deletedInnoDB存储引擎执行DELETE操作删除的行数

Connections连接数
Uptime服务器工作时间
Slow_queries慢查询的次数

MariaDB [test]> show global status like 'Innodb_rows%';
+----------------------+-------+
| Variable_name| Value |
+----------------------+-------+
| Innodb_rows_deleted | 512|
| Innodb_rows_inserted | 1662 |
| Innodb_rows_read | 4557 |
| Innodb_rows_updated | 4 |
+----------------------+-------+
4 rows in set (0.00 sec)

MariaDB [test]> show global status like 'Connection%';
+-----------------------------------+-------+
| Variable_name | Value |
+-----------------------------------+-------+
| Connection_errors_accept | 0 |
| Connection_errors_internal| 0 |
| Connection_errors_max_connections | 0 |
| Connection_errors_peer_address| 0 |
| Connection_errors_select | 0 |
| Connection_errors_tcpwrap | 0 |
| Connections| 15|
+-----------------------------------+-------+
7 rows in set (0.00 sec)

MariaDB [test]> show global status like 'Uptime%';
+---------------------------+---------+
| Variable_name | Value|
+---------------------------+---------+
| Uptime| 1285789 |
| Uptime_since_flush_status | 1285789 |
+---------------------------+---------+
2 rows in set (0.00 sec)

MariaDB [test]> show global status like 'Slow_queries%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Slow_queries | 0 |
+---------------+-------+
1 row in set (0.00 sec)