关于慢查询的一些基础配置
1. 登录mysql
mysql -h $hostip -u$username -p$password
2. 查看慢查询日志的状态:
show variables like'%slow_query_log%';
+---------------------+--------------------------------------+
| Variable_name | Value |
+---------------------+--------------------------------------+
| slow_query_log | OFF |
| slow_query_log_file | /var/lib/mysql/f83789c63cdb-slow.log |
+---------------------+--------------------------------------+
3. 如果上一步log的值是OFF,那么开启慢查询日志(xxx-slow.log):
set global slow_query_log=ON;
4. 查看慢查询临界时间:
show variables like'long_query_time';
+-----------------+----------+
| Variable_name | Value |
+-----------------+----------+
| long_query_time | 10.000000 |
+-----------------+----------+
5. 设置/修改慢查询临界时间,默认为10s:
set long_query_time = 0.5;