错误信息：
ERROR 1045 (28000): Plugin caching_sha2_password could not be loaded: /usr/lib/x86_64-linux-gnu/mariadb19/plugin/caching_sha2_password.so: cannot open shared object file: No such file or directory
解决方案：
- alter user 'root'@'localhost' identified by '123456' password expire never;
- alter user 'root'@'localhost' identified with mysql_native_password BY '123456';
- flush privileges;