2-MySQL 配置之开启慢查询日志

1.查看当前MySQL慢查询配置信息

mysql> show variables like '%slow%';  
+---------------------------+-------------------------+
| Variable_name             | Value                   |
+---------------------------+-------------------------+     
| slow_query_log            | ON   #OFF关闭，ON开启    | 
| slow_query_log_file       | /var/log/mysql-slow.log |
+---------------------------+-------------------------+

mysql> show variables like '%long_query_time%';
+-----------------+----------+
| Variable_name   | Value    |
+-----------------+----------+
| long_query_time | 5.000000 |
+-----------------+----------+

2.临时开启慢查询

#开启慢查询
mysql> set global slow_query_log='ON'; 
#设置慢查询日志存放的位置
mysql> set global slow_query_log_file='/usr/local/mysql/data/mysql-slow.log';
#超过2秒就记录
mysql> set global long_query_time=2;

3.永久开启慢查询

修改my.cnf

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
slow_query_log = ON
slow_query_log_file = /usr/local/mysql/data/mysql-slow.log
long_query_time = 2

[root@localhost ~]# service mysqld restart  #重启生效