版本说明
本机：
jdk 8
使用IntelliJ IDEA调试MyCAT 1.6 release
主机一：droplet CentOS 7.5 x86_64
MyCAT 1.6 release
OpenJDK 1.8
MySQL-Server 5.7
主机二：bandwagon CentOS 6.8 i686
MySQL-Client 5.6
实验过程
0. 调整时区
timedatectl set-local-rtc 1
timedatectl set-timezone Asia/Shanghai
1. MySQL 5.7 安装
为加快速度，使用二进制安装
规划了三个实例
[karenyin@centos-s-karenyin mysql_data]$ tree -L 1
.
├── 10010
├── 10011
├── 10012
├── conf
└── start_mysql.sh
wget https://dev.mysql.com/get/Downloads/MySQL-8.0/mysql-8.0.13-1.el7.x86_64.rpm-bundle.tar
rpm -ivh mysql-community-common-8.0.13-1.el7.x86_64.rpm
rpm -e --nodeps mariadb-libs-5.5.56-2.el7.x86_64
rpm -ivh mysql-community-libs-8.0.13-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-8.0.13-1.el7.x86_64.rpm
yum install -y libaio
rpm -ivh mysql-community-server-8.0.13-1.el7.x86_64.rpm
mysqld --defaults-file='/home/karenyin/mysql_data/conf/10010.cnf' --initialize-insecure
mysql -u -S 你在后面再接个参数， 跳过加载权限表 可以进去改个密码，再退出来。
--skip-grant-tables
mysql --defaults-file='/home/karenyin/mysql_data/conf/10010.cnf'
create database TESTDB;
CREATE USER 'karenyin'@'%' IDENTIFIED BY "123456";
grant all privileges on db_music.* to 'karenyin'@'%' identified by "123456";
CREATE USER 'karenyin'@'localhost' IDENTIFIED BY "123456";
grant all privileges on db_music.* to 'karenyin'@'localhost' identified by "123456";
flush privileges;
CREATE USER "root"@"%" IDENTIFIED BY "123456";
grant all privileges on *.* to 'root'@'%' identified by "123456" with grant option;
flush privileges;
show grants; 查看select user()的授权情况
show grants for karenyin;
show grants for karenyin@'%';