MySQL 5.7版本支持多源复制，MySQL 5.5和5.6不支持。
多源复制可以让多个主节点同时并行进行复制到一个从节点上。一个slave为每个master创建一个复制通道。
至少需要两台主库和一台从库。
多源复制中的主库，可以配置成基于全局事务标准(GTID)的复制，或者基于二进制日志的复制。

IP规划

主库01192.168.174.201
主库02192.168.174.202
从库192.168.174.203

1. 在多源复制的从库中，需要基于表的repositories，和基于文件的repositories不兼容。
在从库上面操作
可以将下面参数添加到参数文件中
master-info-repository=TABLE
relay-log-info-repository=TABLE

master_info_repository
决定包含master状态和连接信息的slave日志，是以文件格式(master.info)，还是以表格式(mysql.slave_master_info)存在。
当没有复制线程执行的时候，可以改变这个参数的值。
这个参数还会对sync_master_info系统参数有直接的影响。

relay_log_info_repository
这个参数决定写到文件（relay-log.info）或表（mysql.slave_relay_log_info）中的中继日志slave节点的位置。只有当没有复制线程执行时，才可修改这个参数的值。
这个参数用于存放中继日志的信息。默认是文件格式，文件的默认名是relay-log.info。
如果是TABLE格式，日志信息会写到mysql.slave_relay_log_info。

动态修改，使用下面命令
STOP SLAVE;
SET GLOBAL master_info_repository = 'TABLE';
STOP SLAVE;
SET GLOBAL relay_log_info_repository = 'TABLE';

mysql> show global variables like '%repositor%';
+---------------------------+-------+
| Variable_name | Value |
+---------------------------+-------+
| master_info_repository| FILE |
| relay_log_info_repository | FILE |
+---------------------------+-------+
2 rows in set (0.03 sec)

mysql> SET GLOBAL master_info_repository = 'TABLE';
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL relay_log_info_repository = 'TABLE';
ERROR 1766 (HY000): Unknown error 1766

mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show global variables like '%repositor%';
+---------------------------+-------+
| Variable_name | Value |
+---------------------------+-------+
| master_info_repository| TABLE |
| relay_log_info_repository | TABLE |
+---------------------------+-------+
2 rows in set (0.01 sec)

编辑从库的其他配置文件
[root@localhost 5505]# vim /mysql_data/cnf/my.cnf
# Log
server-id = 300
log-bin = /mysql_log/binlog/mysql-bin
relay-log = /mysql_log/binlog/product-relay-bin
relay-log-index = /mysql_log/binlog/product-relay-index

之后重启数据库，使得参数生效

2. 修改主库1和主库2参数文件，创建复制用户，创建测试数据
编辑主库的配置文件，注意，每个库的server-id不能相同
[root@localhost install]# vim /etc/my.cnf
# Log
server-id = 100
log-bin = /log/binlog/mysql-bin

之后重启数据库，使得参数生效

创建复制用户
mysql> grant replication slave on *.* to 'repl'@'192.168.174.%' identified by 'repl';
Query OK, 0 rows affected, 1 warning (0.06 sec)
mysql> select version();
+---------------+
| version() |
+---------------+
| 5.7.17-11-log |
+---------------+
1 row in set (0.00 sec)

创建测试数据
主库1
mysql> create database sale;
Query OK, 1 row affected (0.06 sec)

mysql> use sale;
Database changed
mysql> create table sale_record(id int);
Query OK, 0 rows affected (0.16 sec)

mysql> insert into sale_record values(10),(20);
Query OK, 2 rows affected (0.95 sec)
Records: 2 Duplicates: 0 Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.01 sec)

主库2
mysql> use market;
Database changed
mysql> create table market_record(id int)
-> ;
Query OK, 0 rows affected (0.04 sec)

mysql> insert into market_record values (100),(200);
Query OK, 2 rows affected (0.25 sec)
Records: 2 Duplicates: 0 Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.01 sec)

3. 备份主库1和主库2
主库1
[root@MySQL01 mysql_software_57]# bin/mysqldump -uroot -p'root' -h 127.0.0.1 -q --single-transaction --master-data=2 -B sale > /tmp/20171211_sale.sql

主库2
[root@localhost mysql_software_57]# bin/mysqldump -uroot -p'root' -S /mysql_data_57/mysql.sock -q --single-transaction --master-data=2 -B market > /tmp/20171211_market.sql

将主库1和主库2上面的备份文件拷贝到从库上面，进行恢复
在从库上面操作
[root@MySQL03 mysql_software_57]# bin/mysql -uroot -p'root' -h 127.0.0.1 < /tmp/20171211_sale.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@MySQL03 mysql_software_57]# bin/mysql -uroot -p'root' -h 127.0.0.1 < /tmp/20171211_market.sql
mysql: [Warning] Using a password on the command line interface can be insecure.

4. 搭建多源复制
搭建到主库1的复制，将通道起名为master-1
mysql> change master to
-> master_host='192.168.174.201',
-> master_port=3306,
-> master_user='repl',
-> master_password='repl',
-> master_log_file='mysql-bin.000017',
-> master_log_pos=1209
-> FOR CHANNEL 'master-1';
Query OK, 0 rows affected, 1 warning (0.04 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.174.201
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000017
Read_Master_Log_Pos: 1209
Relay_Log_File: mysqld-relay-bin-master@002d1.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-bin.000017
Slave_IO_Running: No
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1209
Relay_Log_Space: 154
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 0
Master_UUID:
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-1
Master_TLS_Version:
1 row in set (0.00 sec)

启动通道master-1的IO和SQL线程
mysql> START SLAVE IO_THREAD FOR CHANNEL 'master-1';
Query OK, 0 rows affected (0.00 sec)

mysql> START SLAVE SQL_THREAD FOR CHANNEL 'master-1';
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.174.201
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000017
Read_Master_Log_Pos: 1209
Relay_Log_File: mysqld-relay-bin-master@002d1.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000017
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1209
Relay_Log_Space: 541
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: 203fe772-177e-11e7-b15c-000c296b3b20
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-1
Master_TLS_Version:
1 row in set (0.00 sec)

启动通道master-2的IO线程和SQL线程
mysql> change master to
-> master_host='192.168.174.202',
-> master_port=3306,
-> master_user='repl',
-> master_password='repl',
-> master_log_file='mysql-bin.000014',
-> master_log_pos=1239
-> FOR CHANNEL 'master-2';
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> START SLAVE IO_THREAD FOR CHANNEL 'master-2';
Query OK, 0 rows affected (0.00 sec)

mysql> START SLAVE SQL_THREAD FOR CHANNEL 'master-2';
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.174.201
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000017
Read_Master_Log_Pos: 1481
Relay_Log_File: mysqld-relay-bin-master@002d1.000002
Relay_Log_Pos: 592
Relay_Master_Log_File: mysql-bin.000017
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1481
Relay_Log_Space: 813
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: 203fe772-177e-11e7-b15c-000c296b3b20
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-1
Master_TLS_Version:
*************************** 2. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.174.202
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000014
Read_Master_Log_Pos: 1239
Relay_Log_File: mysqld-relay-bin-master@002d2.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000014
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1239
Relay_Log_Space: 541
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 2
Master_UUID: 2efd664c-177f-11e7-8323-000c29fcf2cd
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: master-2
Master_TLS_Version:
2 rows in set (0.01 sec)

进行测试
在主库1上面插入数据
mysql> insert into sale_record values(30),(40),(50);
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.01 sec)

在主库2上面插入数据
mysql> insert into market_record values(300),(400),(500);
Query OK, 3 rows affected (0.01 sec)
Records: 3 Duplicates: 0 Warnings: 0

mysql> commit;
Query OK, 0 rows affected (0.01 sec)

在从库上面进行查询
mysql> select * from sale.sale_record;
+------+
| id|
+------+
|10 |
|20 |
|30 |
|40 |
|50 |
+------+
5 rows in set (0.00 sec)

mysql> select * from market.market_record;
+------+
| id|
+------+
| 100 |
| 200 |
| 300 |
| 400 |
| 500 |
+------+
5 rows in set (0.00 sec)
常用命令

启动多源复制

启动所有配置的复制通道的IO线程
mysql> start slave io_thread;
Query OK, 0 rows affected (0.01 sec)

启动所有配置的复制通道的SQL线程
mysql> start slave sql_thread;
Query OK, 0 rows affected (0.01 sec)

启动指定的复制通道
mysql> start slave io_thread for channel 'master-1';
Query OK, 0 rows affected (0.00 sec)

停止多源复制

停止所有配置的复制通道的IO线程
mysql> stop slave io_thread;
Query OK, 0 rows affected (0.01 sec)

停止所有配置的复制通道的SQL线程
mysql> stop slave sql_thread;
Query OK, 0 rows affected (0.00 sec)
停止指定的复制通道
mysql> stop slave sql_thread for channel 'master-1';
Query OK, 0 rows affected, 1 warning (0.00 sec)
重置多源复制的从库

重置所有配置的复制通道
RESET SLAVE;

重置指定的通道
RESET SLAVE FOR CHANNEL 'master-1';