在 Debian Stretch 上安装 LAMP 堆栈后，我遇到了 MySQL / MariaDB 的各种问题（无法从普通用户以 root 身份登录，然后 root 没有权限）。我认为最简单的解决方案是重新安装MariaDB：
# apt-get purge mysql-server mysql-client mysql-common mysql-server-core-5.5 mysql-client-core-5.5
# rm -rf /etc/mysql /var/lib/mysql
# apt-get autoremove
# apt-get autoclean
# apt-get install mariadb-server mariadb-client
但是，安装失败：
Jan 24 23:07:55 debian mysqld[5243]: 2017-01-24 23:07:55 140080623286144 [Note] InnoDB: Initializing buffer pool, size = 128.0M
Jan 24 23:07:55 debian mysqld[5243]: 2017-01-24 23:07:55 140080623286144 [Note] InnoDB: Completed initialization of buffer pool
Jan 24 23:07:55 debian mysqld[5243]: 2017-01-24 23:07:55 140080623286144 …