mysql 慢查询日志记录

环境：

操作系统： CentOS  6.5

数据库：    mysql-5.1.73

1、查看当前慢查询配置

mysql> show variables like 'slow%';
+---------------------+---------------------------------+
| Variable_name       | Value                           |
+---------------------+---------------------------------+
| slow_launch_time    | 2                               |
| slow_query_log      | OFF                             |
| slow_query_log_file | /var/run/mysqld/mysqld-slow.log |
+---------------------+---------------------------------+
3 rows in set (0.00 sec)

2、通过修改 my.cnf 开启监听慢查询

 vi /etc/my.cnf
 
 添加配置
 
[mysqld]
log-slow-queries = /var/lib/mysql/sql_slow.log
#单位秒
long_query_time =
log-queries-not-using-indexes

3、重新启动 mysql

service mysqld restart

4、查看配置是否生效

mysql> show variables like 'slow%';
+---------------------+-----------------------------+
| Variable_name       | Value                       |
+---------------------+-----------------------------+
| slow_launch_time    | 2                           |
| slow_query_log      | ON                          |
| slow_query_log_file | /var/lib/mysql/sql_slow.log |
+---------------------+-----------------------------+
3 rows in set (0.00 sec)

5、测试日志是否记录

执行SQL:

     select sleep(3);

查看记录日志 tail  -300f  sql_slow.log

Query_time :查询使用时间

Lock_time:锁时间
Rows_sent：返回记录条数
Rows_examined：总共记录条数

    Tcp port: 3306  Unix socket: /var/lib/mysql/mysql.sock
    Time                 Id Command    Argument
    # Time: 151019 15:39:04
    # User@Host: [root] @ localhost []
    # Query_time: 3.001364  Lock_time: 0.000000 Rows_sent: 1  Rows_examined: 0
    SET timestamp=1445240344;
    select sleep(3);