标题有点罗嗦，目前出现的问题如下：
当以非root身份登录数据库时，会报错
mysql -u root -p
Enter password:
ERROR 1698 (28000): Access denied for user 'root'@'localhost'而使用root身份访问就没有问题
问题探究
查看root用户使用的认证插件：
mysql> select user,plugin from user where user = 'root';
------ -------------
| user | plugin |
------ -------------
| root | auth_socket |
------ -------------
1 row in set (0.00 sec)MySQL使用的auth_socket是通过Unix套接字进行连接认证[1]
The unix_socket authentication plugin works by calling the getsockopt system call with the SO_PEERCRED socket option, which allows it to retrieve the uid of the process that is connected to the socket. It is then able to get the user name associated with that uid. Once it has the user name, it will authenticate the connecting user as the MariaDB account that has the same user name. [2]
因此可以将认证插件改为 mysql_native_password
解决方法
ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'new_password';
FLUSH PRIVILEGES;另请参阅
[1] https://dev.mysql.com/doc/refman/8.0/en/socket-pluggable-authentication.html
[2] https://mariadb.com/kb/en/authentication-plugin-unix-socket/