mysql 启动报错-server PID file could not be found

[root@yunhe ~]# service mysql stop
MySQL server PID file could not be found!                  [失败]

解决方案如下：

首先查看下与mysql有关的进程

[root@yunhe ~]# ps aux |grep mysq*
root      2019  0.0  0.1   6228  1392 ?        S    09:22   0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/yunhe.pid
mysql     2115  0.0  2.9 353596 30808 ?        Sl   09:22   0:01 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/lib/mysql/yunhe.err --pid-file=/var/lib/mysql/yunhe.pid
500       4258  0.0  1.6  83432 17484 ?        S    09:35   0:01 gedit /usr/share/mysql/my-medium.cnf
root      5555  0.0  0.0   5936   768 pts/0    S+   10:04   0:00 grep mysq*

如果看到上面的内容，那说明mysql相关的进程存在，不过资源调度出现了问题（好像卡死），这时用就要把这些卡死的进程都关闭。
[root@yunhe ~]# kill 2019
[root@yunhe ~]# kill 20115
-bash: kill: (20115) - 没有那个进程
[root@yunhe ~]# kill 2115

然后重新启动mysql
[root@yunhe ~]# service mysql start
Starting MySQL...                                          [确定]
[root@yunhe ~]# mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.4-m7 MySQL Community Server (GPL)

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