初试mysql5.7.2新特性：多源复制（MySQL 5.7 multi-source replication）

多源复制和多主复制的区别：

多主复制示意图：

多源复制示意图：

在my.cnf中添加crash safe特性参数：
master_info_repository=TABLE;
relay_log_info_repository=TABLE;

mysql> change master to master_host="10.186.21.102", master_port=13306, master_user="repl",master_password="repl" for channel="master1";
Query OK, 0 rows affected(0.01 sec)

mysql> change master to master_host="10.186.21.102", master_port=13307, master_user="repl",master_password="repl" for channel="master2";
Query OK, 0 rows affected (0.01 sec)

mysql> select * from mysql.slave_master_info;
+-----------------+-----------------+----------------+---------------+-----------+---------------+-------+---------------+-------------+--------+------------+----------+------------+---------+------------------------+-----------+------+--------------------+------+-------------+---------+-------------+-----------------------+--------------+
| Number_of_lines | Master_log_name | Master_log_pos | Host          | User_name | User_password | Port  | Connect_retry | Enabled_ssl | Ssl_ca | Ssl_capath | Ssl_cert | Ssl_cipher | Ssl_key | Ssl_verify_server_cert | Heartbeat | Bind | Ignored_server_ids | Uuid | Retry_count | Ssl_crl | Ssl_crlpath | Enabled_auto_position | Channel_name |
+-----------------+-----------------+----------------+---------------+-----------+---------------+-------+---------------+-------------+--------+------------+----------+------------+---------+------------------------+-----------+------+--------------------+------+-------------+---------+-------------+-----------------------+--------------+
|              24 |                 |              4 | 10.186.21.102 | repl      | repl          | 13306 |            60 |           0 |        |            |          |            |         |                      0 |      1800 |      | 0                  |      |       86400 |         |             |                     0 | master1      |
|              24 |                 |              4 | 10.186.21.102 | repl      | repl          | 13307 |            60 |           0 |        |            |          |            |         |                      0 |      1800 |      | 0                  |      |       86400 |         |             |                     0 | master2      |
+-----------------+-----------------+----------------+---------------+-----------+---------------+-------+---------------+-------------+--------+------------+----------+------------+---------+------------------------+-----------+------+--------------------+------+-------------+---------+-------------+-----------------------+--------------+
2 rows in set (0.00 sec)

mysql> select * from slave_relay_log_info  ;
+-----------------+------------------------------------+---------------+-----------------+----------------+-----------+-------------------+----+--------------+
| Number_of_lines | Relay_log_name                     | Relay_log_pos | Master_log_name | Master_log_pos | Sql_delay | Number_of_workers | Id | Channel_name |
+-----------------+------------------------------------+---------------+-----------------+----------------+-----------+-------------------+----+--------------+
|               7 | ./mha-db1-relay-bin-master1.000001 |             4 |                 |              0 |         0 |                 0 |  1 | master1      |
|               7 | ./mha-db1-relay-bin-master2.000001 |             4 |                 |              0 |         0 |                 0 |  1 | master2      |
+-----------------+------------------------------------+---------------+-----------------+----------------+-----------+-------------------+----+--------------+

mysql> start slave for channel="master2";
Query OK, 0 rows affected (0.01 sec)

mysql> start slave for channel="master1";
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status for channel="master1"\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.186.21.102
                  Master_User: repl
                  Master_Port: 13306
                Connect_Retry: 60
              Master_Log_File: log_bin.000001
          Read_Master_Log_Pos: 120
               Relay_Log_File: mha-db1-relay-bin-master1.000002
                Relay_Log_Pos: 281
        Relay_Master_Log_File: log_bin.000001
             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: 120
              Relay_Log_Space: 464
              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: 13306
                  Master_UUID: 546b04cc-9621-11e3-95d5-0a98756bb836
             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 the slave I/O thread to update it
           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
1 row in set (0.00 sec)

mysql> show slave status for channel="master2"\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.186.21.102
                  Master_User: repl
                  Master_Port: 13307
                Connect_Retry: 60
              Master_Log_File: log_bin.000001
          Read_Master_Log_Pos: 120
               Relay_Log_File: mha-db1-relay-bin-master2.000002
                Relay_Log_Pos: 281
        Relay_Master_Log_File: log_bin.000001
             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: 120
              Relay_Log_Space: 464
              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: 13307
                  Master_UUID: fba8d917-9621-11e3-95d9-0a98756bb836
             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 the slave I/O thread to update it
           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
1 row in set (0.00 sec)

master1：
mysql> create database master1;

master2：
mysql> create database master2;

slave：
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| master1            |
| master2            |
| mysql              |
| performance_schema |
| test               |
+--------------------+
6 rows in set (0.00 sec)

重启slave命令：
mysql> stop slave for channel="master1";
Query OK, 0 rows affected (0.00 sec)

mysql> stop slave for channel="master2";
Query OK, 0 rows affected (0.01 sec)

重做slave命令：
mysql> reset slave for channel="master2";
Query OK, 0 rows affected (0.33 sec)

mysql> reset slave for channel="master1";
Query OK, 0 rows affected (0.30 sec)

多源复制存在问题：

多源数据库不能有同名库，否则会导致复制失败

master1：

mysql> create database master1;

Query OK, 1 row affected (0.00 sec)

master2：

mysql> create database master2;

Query OK, 1 row affected (0.00 sec)

mysql> create database master1;

Query OK, 1 row affected (0.00 sec)

slave：

show slave status for channel="master2"\G;

Last_SQL_Error: Error 'Can't create database 'master2'; database exists' on query. Default database: 'master2'. Query: 'create database master2'