MySQL多源复制

1. 配置多源复制

1.1 配置环境如下
1.2 从库的重要参数配置
1.3 在Master上导出需要同步的数据库
1.4 在master上创建复制账号
1.5 备份数据导入
1.6 查看备份文件中Master1与Master2的binlog Pos位置
1.7 Slave进行change master操作
1.8 开启主从复制

2. 监控多源复制

MySQL多源复制使slave能够同时从多个源master接收事务。多源复制可用于将多个服务器备份到单个服务器，合并表分片，以及将来自多个服务器的数据合并到单个服务器。应用事务时，多源复制不会实现任何冲突检测或解决，如果需要，这些任务将留给应用程序。在多源复制拓扑中，slave服务器应从每个接收事务的主服务器创建复制通道。以下部分介绍如何设置多源复制。

1. 配置多源复制

介绍如何配置多源复制拓扑，并提供有关配置master和slave的详细信息。这种拓扑需要至少两个master设备和一个slave设备配置。

1.1 配置环境如下

类型	IP	端口号	server-id	复制通道
master	192.168.56.100	3306	1003306	master1
master	192.168.56.100	3307	1003307	master2
slave	192.168.56.200	3308	2003308

1.2 从库的重要参数配置

在多源复制中，slave需要基于TABLE的存储库。多源复制与基于FILE的存储库不兼容。mysqld使用的存储库类型可以在启动时配置，也可以动态配置。

启动时配置my.cnf

master-info-repository=TABLE

relay-log-info-repository=TABLE

在线动态配置

STOP SLAVE;

SET GLOBAL master_info_repository = 'TABLE';

SET GLOBAL relay_log_info_repository = 'TABLE';

1.3 在Master上导出需要同步的数据库

利用mysqldump进行备份及恢复，mysqldump的使用方法见博客MySQL备份恢复

在master1上

mysqldump -S /tmp/mysql3306.sock --master-data=2 --single-transaction --add-drop-database --databases employees > /tmp/empdb.sql

在master2上

mysqldump -S /tmp/mysql3307.sock --master-data=2 --single-transaction --add-drop-database --databases test > /tmp/testdb.sql

把备份传输到slave上

scp /tmp/empdb.sql /tmp/testdb.sql mysqldb2:/data/backup/

1.4 在master上创建复制账号

在master1上

mysql> create user 'repl'@'%' identified by 'wanbin';

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';

在master2上

mysql> create user 'repl'@'%' identified by 'wanbin';

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';

1.5 备份数据导入

mysql -S /tmp/mysql3308.sock < empdb.sql 

ERROR 1840 (HY000) at line 24: @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.

#出现错误

#解决方法：

mysql> reset master;

mysql -S /tmp/mysql3308.sock < empdb.sql

mysql -S /tmp/mysql3308.sock < testdb.sql

1.6 查看备份文件中Master1与Master2的binlog Pos位置

cat empdb.sql |grep "CHANGE MASTER"

-- CHANGE MASTER TO MASTER_LOG_FILE='my3306_binlog.000004', MASTER_LOG_POS=194;

cat testdb.sql |grep "CHANGE MASTER"

-- CHANGE MASTER TO MASTER_LOG_FILE='my3307_binlog.000011', MASTER_LOG_POS=194;

1.7 Slave进行change master操作

#创建复制账号

create user 'repl'@'%' identified by 'wanbin';

GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';

#change master

CHANGE MASTER TO

  MASTER_HOST='192.168.56.100',

  MASTER_USER='repl',

  MASTER_PASSWORD='wanbin',

  MASTER_PORT=3306,

  MASTER_LOG_FILE='my3306_binlog.000004',

  MASTER_LOG_POS=194

  FOR CHANNEL 'master1';

CHANGE MASTER TO

  MASTER_HOST='192.168.56.100',

  MASTER_USER='repl',

  MASTER_PASSWORD='wanbin',

  MASTER_PORT=3307,

  MASTER_LOG_FILE='my3307_binlog.000011',

  MASTER_LOG_POS=194

  FOR CHANNEL 'master2';

1.8 开启主从复制

可以通过start slave命令开启所有复制，也可以通过 start slave for channel 来分别开启。

mysql> start slave for CHANNEL 'master1';

mysql> start slave for CHANNEL 'master2';

2. 监控多源复制

要监视复制通道的状态，需要以下选项：

使用复制Performance Schema表。这些表的第一列是Channel_Name。这使您可以基于Channel_Name作为键来编写复杂查询。

使用SHOW SLAVE STATUS FOR CHANNEL Channel_Name。默认情况下，如果未使用FOR CHANNEL通道子句，则此语句显示所有通道的从站状态，每个通道一行。标识符Channel_name将添加为结果集中的列。如果提供了FOR CHANNEL通道子句，则结果仅显示指定复制通道的状态。

root@localhost [test] 15:46:02>SHOW SLAVE STATUS FOR CHANNEL 'master1'\G

*************************** 1. row ***************************

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 192.168.56.100

                  Master_User: repl

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: my3306_binlog.000004

          Read_Master_Log_Pos: 973

               Relay_Log_File: mysqldb2-relay-bin-master1.000002

                Relay_Log_Pos: 1103

        Relay_Master_Log_File: my3306_binlog.000004

             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: 973

              Relay_Log_Space: 1321

              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: 1003306

                  Master_UUID: 7390a401-b705-11e8-9ed9-080027b0b461

             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: 7390a401-b705-11e8-9ed9-080027b0b461:10-13

            Executed_Gtid_Set: 3a068bf8-cdeb-11e8-8176-080027b0b461:1-16,

7390a401-b705-11e8-9ed9-080027b0b461:10-13,

d934e7cb-d1d1-11e8-85ce-0800275b8a9a:1-3

                Auto_Position: 0

         Replicate_Rewrite_DB:

                 Channel_Name: master1

           Master_TLS_Version:

1 row in set (0.00 sec)

使用Performance Schema.replication_connection_status 表监控

root@localhost [test] 15:49:21>use performance_schema

Database changed

root@localhost [performance_schema] 15:49:43>select * from replication_connection_status\G

*************************** 1. row ***************************

             CHANNEL_NAME: master1

               GROUP_NAME:

              SOURCE_UUID: 7390a401-b705-11e8-9ed9-080027b0b461

                THREAD_ID: 44

            SERVICE_STATE: ON

COUNT_RECEIVED_HEARTBEATS: 64

 LAST_HEARTBEAT_TIMESTAMP: 2018-10-17 15:49:41

 RECEIVED_TRANSACTION_SET: 7390a401-b705-11e8-9ed9-080027b0b461:10-13

        LAST_ERROR_NUMBER: 0

       LAST_ERROR_MESSAGE:

     LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00

*************************** 2. row ***************************

             CHANNEL_NAME: master2

               GROUP_NAME:

              SOURCE_UUID: 3a068bf8-cdeb-11e8-8176-080027b0b461

                THREAD_ID: 47

            SERVICE_STATE: ON

COUNT_RECEIVED_HEARTBEATS: 58

 LAST_HEARTBEAT_TIMESTAMP: 2018-10-17 15:49:23

 RECEIVED_TRANSACTION_SET: 3a068bf8-cdeb-11e8-8176-080027b0b461:14-16

        LAST_ERROR_NUMBER: 0

       LAST_ERROR_MESSAGE:

     LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00

2 rows in set (0.00 sec)