MySQL复制(四)—多源(主)复制

（一）多主复制概述

所谓多主复制，是将多个主库的数据复制到一个从库中。通常用于数据仓库整合数据，比如OLTP系统为了分散业务压力，对业务进行分库分表，当要对数据进行分析的时候，可以使用多主复制将数据整合到同一个数据库实例上，便于统一分析。MySQL从5.7版本开始支持多主复制。

本文通过搭建多主复制环境来了解MySQL多主复制的特点。

（二）基础环境

	主库1	主库2	从库
服务器IP地址	192.168.10.11	192.168.10.12	192.168.10.13
MySQL版本	5.7.24	5.7.24	5.7.24
待同步的数据库	db1	db2	从库上创建空库db1和db2

（三）多主复制搭建

(3.1)创建用于复制的用户(主库执行)

在2个主数据库上创建用于复制的用户rep，用户需具有“replication slave”权限。每个数据库上复制账号可以不相同，这里为了测试方便，创建为相同的账号。

mysql> grant replication slave on *.* to 'rep'@'%' identified by '123';

(3.2)参数修改（从库执行）

-- 重启数据库失效，建议配置在启动文件中
mysql> SET GLOBAL master_info_repository = 'TABLE';
mysql> SET GLOBAL relay_log_info_repository = 'TABLE';

(3.3)主库创建测试数据，备库创建空数据库

主库1：

mysql> create database db1;

mysql> use db1

mysql> create table test01
    -> (
    ->   id1   int  not null auto_increment,
    -> name  varchar(30),
    -> primary key(id1)
    -> );

mysql> insert into test01 values(1,'a');

主库2：

mysql> create database db2;

mysql> use db2

mysql> create table test02
    -> (
    ->   id2   int  not null auto_increment,
    -> name  varchar(30),
    -> primary key(id2)
    -> );

mysql> insert into test02 values(2,'b');

备库：

mysql> create database db1;

mysql> create database db2;

(3.4)将主库数据手动同步到备库（从库执行）

在备库上执行远程导出操作：

[root@slavedb ~]# mysqldump -uroot -p123456 -h192.168.10.11  --master-data=2 --set-gtid-purged=OFF -P3306 db1 --single-transaction  > db1.sql
[root@slavedb ~]# mysqldump -uroot -p123456 -h192.168.10.12  --master-data=2 --set-gtid-purged=OFF -P3306 db2 --single-transaction  > db2.sql

在备库上执行导入操作：

[root@slavedb ~]# mysql -h192.168.10.13 -P3306 -uroot -p123456 db1 < /root/db1.sql 
[root@slavedb ~]# mysql -h192.168.10.13 -P3306 -uroot -p123456 db2 < /root/db2.sql

(3.5)开启从库同步db1（从库执行）

STEP1:确认主库导出到的日志位置

cat db1.sql |grep "CHANGE MASTER"|less
-- CHANGE MASTER TO MASTER_LOG_FILE='master-bin.000029', MASTER_LOG_POS=1835;

STEP2：将主库1添加到复制环境

mysql> change master to 
    -> master_host='192.168.10.11',
    -> master_port=3306,
    -> master_user='rep',
    -> master_password='123',
    -> master_log_file='master-bin.000029',
    -> master_log_pos=1835 for channel 'ch1';
Query OK, 0 rows affected, 2 warnings (0.02 sec)

STEP3:开启主库1的复制

mysql> start slave for channel 'ch1';
Query OK, 0 rows affected (0.00 sec)

(3.6)开启从库同步db2（从库执行）

STEP1:确认主库导出到的日志位置

cat db2.sql |grep "CHANGE MASTER"|less
-- CHANGE MASTER TO MASTER_LOG_FILE='master-bin.000029', MASTER_LOG_POS=1419;

STEP2：将主库2添加到复制环境

change master to 
master_host='192.168.10.12',
master_port=3306,
master_user='rep',
master_password='123',
master_log_file='master-bin.000029',
master_log_pos=1419 for channel 'ch2';

STEP3:开启主库2的复制

mysql> start slave for channel 'ch2';

(3.7)测试数据复制是否正常

主库1：

mysql> insert into test01 values(11,'aa');

主库2：

mysql> insert into test02 values(22,'bb');

备库：

mysql> select * from db1.test01;
+-----+------+
| id1 | name |
+-----+------+
|   1 | a    |
|  11 | aa   |
+-----+------+
2 rows in set (0.00 sec)

mysql> select * from db2.test02;
+-----+------+
| id2 | name |
+-----+------+
|   2 | b    |
|  22 | bb   |
+-----+------+
2 rows in set (0.00 sec

数据复制正常。

(3.8)确认复制状态

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.10.11
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-bin.000029
          Read_Master_Log_Pos: 1835
               Relay_Log_File: slavedb-relay-bin-ch1.000002
                Relay_Log_Pos: 321
        Relay_Master_Log_File: master-bin.000029
             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: 1835
              Relay_Log_Space: 534
              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: caa64a22-481a-11ea-b0f1-000c29fb6200
             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: 8a885841-481c-11ea-bdc4-000c29840f0f:1-10,
caa64a22-481a-11ea-b0f1-000c29fb6200:1-466040
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: ch1
           Master_TLS_Version: 
*************************** 2. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.10.12
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-bin.000029
          Read_Master_Log_Pos: 1419
               Relay_Log_File: slavedb-relay-bin-ch2.000002
                Relay_Log_Pos: 321
        Relay_Master_Log_File: master-bin.000029
             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: 1419
              Relay_Log_Space: 534
              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: caa64a22-481a-11ea-b0f1-000c29fb6200
             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: 8a885841-481c-11ea-bdc4-000c29840f0f:1-10,
caa64a22-481a-11ea-b0f1-000c29fb6200:1-466040
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: ch2
           Master_TLS_Version: 
2 rows in set (0.00 sec)

【完成】

附录：

MySQL复制(replication)文档集合:

1.复制概述
2.基于二进制日志文件位置(binlog)配置复制
3.基于全局事物标识符(GTID)配置复制
4.多源复制
5.级联复制
6.半同步复制
7.延迟复制
8.复制过滤规则
9.对复制进行故障排除
10.故障切换
11.复制管理

MySQL复制(四)—多源(主)复制

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