在我的情况下，似乎我不能真正杀死mysql进程，当我运行

sudo service mysql stop
ps -ef | grep mysql

mysql进程一直在那里，看起来它阻塞了套接字文件，新的mysql进程不能自己创建它。

这很有帮助

cd /var/run
sudo cp mysqld/ mysqld.bc -rf
sudo chown mysql:mysql mysqld.bc/
sudo service mysql stop
sudo cp mysqld.bc/ mysqld -rf
sudo chown mysql:mysql mysqld -R
sudo /usr/sbin/mysqld --skip-grant-tables --skip-networking &

现在我能够登录数据库使用

mysql -u root

然后更新root密码:

UPDATE user SET authentication_string=password('YOURPASSWORDHERE') WHERE user='root';
FLUSH PRIVILEGES;

PS:我在更新根密码时遇到了麻烦，似乎是“auth_socket”插件的问题，所以我必须创建具有完整权限的新用户

insert into user set `Host` = "localhost", `User` = "super", `plugin` = "mysql_native_password", `authentication_string` = NULL, `password_expired` = "N", `password_lifetime` = NULL, `account_locked` = "N", `Select_priv` = "Y",
`Insert_priv` = "Y", `Update_priv` = "Y", `Delete_priv` = "Y", `Create_priv` = "Y", `Drop_priv` = "Y", `Reload_priv` = "Y", `Shutdown_priv` = "Y", `Process_priv` = "Y", `File_priv` = "Y",
`Grant_priv` = "Y",  `References_priv` = "Y", `Index_priv` = "Y", `Alter_priv` = "Y", `Show_db_priv` = "Y", `Super_priv` = "Y", `Create_tmp_table_priv` = "Y", `Lock_tables_priv` = "Y",
`Execute_priv` = "Y", `Repl_slave_priv` = "Y",  `Repl_client_priv` = "Y",  `Create_view_priv` = "Y", `Show_view_priv` = "Y", `Create_routine_priv` = "Y", `Alter_routine_priv` = "Y",
`Create_user_priv` = "Y",  `Event_priv` = "Y", `Trigger_priv` = "Y", `Create_tablespace_priv` = "Y";

这将创建一个没有密码的用户“super”，然后你可以连接mysql -u super

This error can also occur if you try to change the directory where the database is stored, but imput the wrong directory in the configuration file (like a typo in the second drive as D instead of the accurate D_). Instead of telling you the typo directory does not exist, it will tell you that you lack permission to access it (leading you to try to change the permissions for the typo directory, which it will let you do). So if you get this error while changing directories, double check the configuration file and make sure you don't have a typo.

当我停止mysql服务时，我得到了完全相同的错误，这里如何解决它:通过(重新)启动mysql使用这些命令:

sudo systemctl start mysql

or

sudo systemctl restart mysql

解决方案1 清除(或删除如果你想保留数据库)任何mysql包，重新重复安装:

sudo apt purge "mysql*"

-Autoremove包

sudo apt autoremove

-停止apparmor服务

sudo systemctl stop apparmor

-让apparmor放弃它的配置文件(我以为用stop就够了，但对我来说不是。systemctl不起作用)

sudo service apparmor teardown

重新安装mysql服务器

sudo apt install mysql-server

安装apparmor-utils，在apparmor中为mysql创建一个允许mysql运行的配置文件

sudo apt install apparmor-utils

检查mysql-server的状态(必须是Active(running))

sudo systemctl status mysql

在apparmor中生成mysql的配置文件

sudo aa-genprof mysql

在其他终端运行mysql(输入root密码)

mysql -u root -p

当apparmor在另一个终端生成配置文件时，在MySQL中执行-do操作

创建数据库中的食物

-切换到另一个终端，按“s”(提示说这是“扫描”)

-对你认为合适的apparmor的政策说“是”(我猜所有的mysql)，说“是”按“a”允许

-按“f”完成apparmor配置文件

-重启apparmor服务

sudo systemctl start apparmor

检查一下你是否可以在其他终端上使用mysql

Mysql>exit

mysql -u root -p

如果一切正常，您可以从命令行使用mysql。

对我来说，更新解决了这个问题:

在Ubuntu上:

sudo apt-get update
sudo apt-get upgrade

CentOS:

sudo yum update

我用重启mysql解决了这个问题

/etc/init.d/mysql stop

and

/etc/init.d/mysql start

就是这样。