1.查看慢查詢變量
```
show variables like '%long%';
```
2.查詢mysql運行多久命令
```
show status like 'uptime';
```
3.查詢啟動mysql后多少條查詢語句
```
show status like 'com_Select';
```
4.查看當前連接數
```
show status like 'connections'
```
5.設置慢查詢時間
```
set long_query_time = 秒為單位;
```
6.安全啟動mysql 打開慢查詢記錄
