忘记了MySQL数据库的root密码，怎么办?

大家往往会想到skip-grant-tables参数，具体步骤如下：

1. 关闭MySQL数据库，因为root密码忘记了，mysqladmin无法使用，此刻，只能经过kill pid关闭程序。

在这里，科普一下kill 和kill -9的区别

mysql> select user,host,password from test.user; +------+-----------+-------------------------------------------+ | user | host | password | +------+-----------+-------------------------------------------+ | root | localhost | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | +------+-----------+-------------------------------------------+ 1 row in set (0.00 sec)

mysql> update test.user set password=password("hello") where user="root" and host="localhost";
Query OK, 1 row affected (0.15 sec)
Rows matched: 1 Changed: 1 Warnings: 0

3. 将上述三个文件copy回源数据库

4. 获取mysqld的pid，经过kill -HUP `pidof mysqld`方式让mysqld进程重新加载配置文件

[root@keepalived01 ~]# mysql -phello
Warning: Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
[root@keepalived01 ~]# kill -HUP 4283 [root@keepalived01 ~]# mysql -phello
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2528 Server version: 5.6.26 MySQL Community Server (GPL)

Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> 

经过上述输出能够看出，kill -HUP之前，直接用密码hello登录被回绝，kill -HUP之后，就能够直接登录了。

当然，以上方法仅供参考，在生产上慎用，毕竟安全名列前茅，天晓得哪里会出现问题。