Mysql 5.7 升级为MariaDB 10.4 步骤

Ubuntu 16的默认mysql版本比较低，很多新的数据库要求越来越高，所以手动升级更换为MariaDB 10.4，步骤如下

停止原有MySQL服务并卸载

sudo service stop mysql
sudo service mysql stop
sudo apt-get remove --purge mysql-server mysql-client mysql-common
sudo apt autoremove
sudo service nginx stop
sudo apt autoremove
sudo apt-get autoremove

添加MariaDB的安装源，查询网址https://downloads.mariadb.org/mariadb/repositories/

sudo apt-get install software-properties-common gnupg-curl
sudo apt-key adv --fetch-keys 'https://mariadb.org/mariadb_release_signing_key.asc'
sudo add-apt-repository 'deb [arch=amd64,arm64,i386,ppc64el] https://ftp.heanet.ie/mirrors/mariadb/repo/10.4/ubuntu xenial main'
sudo apt-get install apt-transport-https ca-certificates
sudo apt update
sudo apt install mariadb-server
sudo service mysql start

安装完成，但是我遇到了“Your privilege table structure seems to be older than this MySQL version”错误，以及无法使用mysqdump导出数据，所以还要手动更新数据库

mysql_upgrade --force -u root -p