MySQL的GTID复制与传统复制的相互切换

MySQL的GTID复制与传统复制的相互转换

• 1. GTID复制转换成传统复制
• 1.1 环境准备
• 1.2 停止slave
• 1.3 查看当前主从状态
• 1.4 change master
• 1.5 启动主从复制
• 1.6 在线关闭主从服务器的GTID
• 2. 传统复制转换成GTID复制
• 2.1 环境准备
• 2.2 将enforce_gtid_consistency设置为warn
• 2.3 将enforce_gtid_consistency设置为on
• 2.4 设置GTID模式为off_permissive
• 2.5 设置GTID模式为on_permissive
• 2.6 检查从库Ongoing_anonymous_transaction_count状态值
• 2.7 确保所有的匿名事务已经被完全复制到所有的slave上
• 2.8 设置GTID_MODE为on
• 2.9 change master

1. GTID复制转换成传统复制

上篇博文已经介绍了MySQL 5.7版本的GTID复制模式的搭建，下面操作将GTID复制转换成传统复制模式。

1.1 环境准备

类型	ip	prot	server-id
master	192.168.56.100	3307	1003307
slave	192.168.56.200	3307	2003307

1.2 停止slave

root@localhost [(none)] 09:38:41>stop slave

1.3 查看当前主从状态

记录Relay_Master_Log_File和Exec_Master_Log_Pos信息。

root@localhost [(none)] 09:41:22>show slave status\G
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 192.168.56.100
                  Master_User: repl
                  Master_Port: 3307
                Connect_Retry: 60
              Master_Log_File: my3307_binlog.000005
          Read_Master_Log_Pos: 194
               Relay_Log_File: mysqldb2-relay-bin.000010
                Relay_Log_Pos: 375
        Relay_Master_Log_File: my3307_binlog.000005
             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: 194
              Relay_Log_Space: 585
              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: 1003307
                  Master_UUID: 3a068bf8-cdeb-11e8-8176-080027b0b461
             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: 3a068bf8-cdeb-11e8-8176-080027b0b461:1-12
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

1.4 change master

根据上面记录的Relay_Master_Log_File和Exec_Master_Log_Pos信息，change master：

root@localhost [(none)] 09:41:26>change master to master_log_file='my3307_binlog.000005',master_log_pos=194,master_auto_position=0;
Query OK, 0 rows affected (0.01 sec)

#参数解释：
master_auto_position=0 表示禁用master_auto_position

1.5 启动主从复制

root@localhost [test] 09:51:28>start slave;

1.6 在线关闭主从服务器的GTID

root@localhost [test] 09:55:01> set global gtid_mode=on_permissive;
Query OK, 0 rows affected (0.01 sec)

root@localhost [test] 09:55:25> set global gtid_mode=off_permissive;
Query OK, 0 rows affected (0.01 sec)

root@localhost [test] 09:55:58> set global gtid_mode=off;
Query OK, 0 rows affected (0.01 sec)

root@localhost [test] 09:56:09> set global enforce_gtid_consistency = 0;
Query OK, 0 rows affected (0.00 sec)

root@localhost [test] 09:57:34> show variables like '%gtid%';
+----------------------------------+-----------+
| Variable_name                    | Value     |
+----------------------------------+-----------+
| binlog_gtid_simple_recovery      | ON        |
| enforce_gtid_consistency         | OFF       |
| gtid_executed_compression_period | 1000      |
| gtid_mode                        | OFF       |
| gtid_next                        | AUTOMATIC |
| gtid_owned                       |           |
| gtid_purged                      |           |
| session_track_gtids              | OFF       |
+----------------------------------+-----------+
8 rows in set (0.01 sec)

可以把 gtid_mode=off 与 enforce_gtid_consistency=OFF 写入配置文件my.cnf中，重启之后也能生效。

2. 传统复制转换成GTID复制

此博文介绍了MySQL 5.7版本的传统复制模式的搭建，下面操作将传统复制转换成GTID复制模式。

2.1 环境准备

类型	ip	prot	server-id
master	192.168.56.100	3306	1003306
slave	192.168.56.200	3306	2003306

2.2 将enforce_gtid_consistency设置为warn

在MySQL每个实例上， 将enforce_gtid_consistency设置为warn

root@localhost [(none)] 10:21:01> set @@global.enforce_gtid_consistency=warn;

【注意】：执行完这条语句后，如果出现GTID不兼容的语句用法，会在error log记录相关信息，那么需要调整该程序避免不兼容的写法，直到完全没有不兼容的语句。

2.3 将enforce_gtid_consistency设置为on

在 2.2完成后，如果没有不兼容语句，可以把MySQL每个实例的ENFORCE_GTID_CONSISTENCY值设置为on。

root@localhost [(none)] 11:05:11> set @@global.enforce_gtid_consistency=on;
Query OK, 0 rows affected (0.00 sec)

2.4 设置GTID模式为off_permissive

将所有MySQL实例的GTID模式设置为off_permissive

root@localhost [(none)] 11:06:55>SET @@GLOBAL.GTID_MODE = OFF_PERMISSIVE;
Query OK, 0 rows affected (0.01 sec)

2.5 设置GTID模式为on_permissive

root@localhost [(none)] 11:12:20> SET @@GLOBAL.GTID_MODE = ON_PERMISSIVE;
Query OK, 0 rows affected (0.01 sec)

2.6 检查从库Ongoing_anonymous_transaction_count状态值

检查从库Ongoing_anonymous_transaction_count状态值是否为0，如果为0，一味着没有等待的事务，可以进行下一步操作

root@localhost [(none)] 11:13:09>SHOW STATUS LIKE 'ONGOING_ANONYMOUS_TRANSACTION_COUNT';
+-------------------------------------+-------+
| Variable_name                       | Value |
+-------------------------------------+-------+
| Ongoing_anonymous_transaction_count | 0     |
+-------------------------------------+-------+
1 row in set (0.00 sec)

2.7 确保所有的匿名事务已经被完全复制到所有的slave上

root@localhost [(none)] 11:29:55>show slave status\G
*************************** 1. row ***************************
...
        Relay_Master_Log_File: my3306_binlog.000090
...
          Exec_Master_Log_Pos: 194
...

#在slave上使用函数：
root@localhost [(none)] 11:30:01>SELECT MASTER_POS_WAIT('my3306_binlog.000090', 194);
+----------------------------------------------+
| MASTER_POS_WAIT('my3306_binlog.000090', 194) |
+----------------------------------------------+
|                                            0 |
+----------------------------------------------+
1 row in set (0.00 sec)
返回结果大于或等于0就说明匿名事务已经全部复制完成

2.8 设置GTID_MODE为on

root@localhost [(none)] 11:31:36>SET @@GLOBAL.GTID_MODE = ON;
Query OK, 0 rows affected (0.01 sec)

2.9 change master

root@localhost [(none)] 11:37:17>STOP slave;
Query OK, 0 rows affected (0.00 sec)

root@localhost [(none)] 11:37:24>change master to master_auto_position=1;
Query OK, 0 rows affected (0.00 sec)

root@localhost [(none)] 11:37:52>start slave;
Query OK, 0 rows affected (0.00 sec)