多源复制就是多个master复制，允许一个slave对应多个master；

change master语法

CHANGE MASTER TO option [, option] ... [ channel_option ] option:    MASTER_BIND = 'interface_name'  | MASTER_HOST = 'host_name'  | MASTER_USER = 'user_name'  | MASTER_PASSWORD = 'password'  | MASTER_PORT = port_num  | MASTER_CONNECT_RETRY = interval  | MASTER_RETRY_COUNT = count  | MASTER_DELAY = interval  | MASTER_HEARTBEAT_PERIOD = interval  | MASTER_LOG_FILE = 'master_log_name'  | MASTER_LOG_POS = master_log_pos  | MASTER_AUTO_POSITION = {0|1}  | RELAY_LOG_FILE = 'relay_log_name'  | RELAY_LOG_POS = relay_log_pos  | MASTER_SSL = {0|1}  | MASTER_SSL_CA = 'ca_file_name'  | MASTER_SSL_CAPATH = 'ca_directory_name'  | MASTER_SSL_CERT = 'cert_file_name'  | MASTER_SSL_CRL = 'crl_file_name'  | MASTER_SSL_CRLPATH = 'crl_directory_name'  | MASTER_SSL_KEY = 'key_file_name'  | MASTER_SSL_CIPHER = 'cipher_list'  | MASTER_SSL_VERIFY_SERVER_CERT = {0|1}  | MASTER_TLS_VERSION = 'protocol_list'  | IGNORE_SERVER_IDS = (server_id_list)channel_option:     FOR CHANNEL channelserver_id_list:    [server_id [, server_id] ... ]

一、环境配置 master 192.168.0.109 master 192.168.0.112
slave 192.168.0.110
确保都开启gtid_mode，基于事务的复制。配置如下： [mysqld] gtid-mode=on enforce-gtid-consistency=true
避免relay.info更新不及时，SLAVE 重启后导致的主从复制出错，，在从服务器上实现事故安全功能，增加配置： master_info_repository=TABLE relay_log_info_repository=TABLE
对于多源复制是必须的不然会出现错误： ERROR 3077 (HY000): To have multiple channels, repository cannot be of type FILE; Please check the repository configuration and convert them to TABLE. 查看：show variables like 'gtid_mode';
二、配置步骤 1.在master创建复制用户。 mysql>create user 'repltest'@'192.168.0.%' identified by 'Repltest123#@!'; mysql>grant replication slave on *.* to 'repltest'@'192.168.0.%';
2.在slave配置change master change master to master_host='192.168.0.109', master_user='repltest', master_password='Repltest123#@!', master_auto_position=1 FOR CHANNEL 'channe1'; 启动复制 start slave FOR CHANNEL 'channe1';
change master to master_host='192.168.0.112', master_user='repltest', master_password='Repltest123#@!', MASTER_AUTO_POSITION=1 FOR CHANNEL 'channe2'; 启动复制 start slave FOR CHANNEL 'channe2';
可以通过show slave status \G查看复制状态。如果同步相同库，同一张表，需要处理，库和表创建冲突以及，表主键冲突情况。 3.可以查看performance_schema下的复制表变化 show tables like 'replication%';
另外可以通过如下全局参数设置多线程复制，提高复制速度： 在slave服务器上停止所有链路的复制 stop slave [for channel 'channel'] set global slave_parallel_type='logical_clock' 并发类型， 默认DATAbase set global slave_parallel_workers=4 并发工作线程数 默认为0 start slave [for channel 'channel'] 重新启动复制链接。 通过查看线程数： show processlist;
查询系统视图的变化： replication_applier_status_by_coordinator 协调复制线程 replication_applier_status_by_worker 复制线程的工作状态。