MySQL使用federated进行数据同步
1、参考博客：
https://blog.csdn.net/wyb213080286/article/details/38493753/；
https://blog.csdn.net/bufanrong/article/details/84063415?utm_medium=distribute.pc_relevant.none-task-blog-baidujs-2；
https://www.cnblogs.com/hstone16/p/13050481.html。
2、主从库确定（Linux系统）：
在从库添加federated插件，具体操作如下：
（1）查询插件：以下是FEDERATED插件没有安装或者没有启用的情况；
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)（2）安装插件：
mysql>install plugin federated soname ‘ha_federated.so’;（3）执行以下步骤：
进入mysql文档下 配置/etc/my.conf，设置federated为默认启动
[root@localhost etc]# vi /etc/my.conf 插入
[mysqld]
federated（4）重启MySQL服务：
[root@localhost etc]# /etc/init.d/mysqld stop
Shutting down MySQL......
[root@localhost etc]# /etc/init.d/mysqld start
Starting MySQL.. （5）再次查询插件是否启用（FEDERATED为yes则完成安装、启用）：
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine | Support | Comment | Transactions | XA | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
| FEDERATED | YES | Federated MySQL storage engine | NO | NO | NO |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+3、复制主库建表信息：
CREATE TABLE `sys_teacher` (
`id` varchar(32) CHARACTER SET utf8 NOT NULL COMMENT '主键id',
`name` varchar(100) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '讲师名称',
`photo` varchar(100) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '照片',
`sex` varchar(10) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '性别',
`unit` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '讲师单位',
`education` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '学历',
`major` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '专业方向',
`technical_title` varchar(100) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '职称',
`rank` varchar(100) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '职级',
`synopsis` text COLLATE utf8mb4_bin COMMENT '简介',
`speciality` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '特长',
`create_by` varchar(64) CHARACTER SET utf8mb4 DEFAULT '' COMMENT '创建者',
`create_time` datetime DEFAULT NULL COMMENT '创建时间',
`update_by` varchar(64) CHARACTER SET utf8mb4 DEFAULT '' COMMENT '更新者',
`update_time` datetime DEFAULT NULL COMMENT '更新时间',
`phone` varchar(11) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '教师电话',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin COMMENT='讲师';
4、设置从库表信息，进行同步：
注：主库需要先新建一个远程访问的账号：
创建账号
本地访问：
create user username@localhost identified by 'password';
外网访问：
create user 'username'@'%' identified by 'password';
flush privileges;
账号授权database_name数据库所有权限
grant all privileges on `database_name`.* to 'username'@'%' identified by 'password';
flush privileges;
只读权限
grant select on 数据库名称.* to 'username'@'%' identified by 'password';
flush privileges;
-- select 查询权限，all privileges 所有权限或指定select,delete,update,create,drop权限
-- database1 数据库
-- username 用户账号
-- password 密码
-- % 所有电脑可访问从库进行同步/备份：
CREATE TABLE `sys_teacher` (
`id` varchar(32) CHARACTER SET utf8 NOT NULL COMMENT '主键id',
`name` varchar(100) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '讲师名称',
`photo` varchar(100) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '照片',
`sex` varchar(10) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '性别',
`unit` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '讲师单位',
`education` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '学历',
`major` varchar(200) CHARACTER SET utf8mb4 DEFAULT NULL COMMENT '专业方向',
`technical_title` varchar(100) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '职称',
`rank` varchar(100) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '职级',
`synopsis` text COLLATE utf8mb4_bin COMMENT '简介',
`speciality` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '特长',
`create_by` varchar(64) CHARACTER SET utf8mb4 DEFAULT '' COMMENT '创建者',
`create_time` datetime DEFAULT NULL COMMENT '创建时间',
`update_by` varchar(64) CHARACTER SET utf8mb4 DEFAULT '' COMMENT '更新者',
`update_time` datetime DEFAULT NULL COMMENT '更新时间',
`phone` varchar(11) COLLATE utf8mb4_bin DEFAULT NULL COMMENT '教师电话',
PRIMARY KEY (`id`)
) ENGINE=FEDERATED
CONNECTION='mysql://主库访问的用户名:主库访问的密码@主库访问的ip:主库访问的端口号/数据库名称/sys_teacher';执行以下内容（不清楚作用），如果需要多次同步，只需要执行一次就OK；
mysql> GRANT ALL PRIVILEGES ON *.* TO 'usrname'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;
查询从库所添加表的数据：
mysql> select count(*) from sys_teacher;