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'