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MySQL5.7在线开启/关闭GTID

环境介绍

Part1:写在最前

截止本文撰写当日，MySQL5.7.16是官网的最新稳定版，本文将用MySQL5.7.16来进行演示。从MySQL5.6开始，支持了GTID复制模式，这种模式其实是把双刃剑，虽然容易搭建主从复制了，但使用不当，就容易出现一些错误，例如error 1236。在MySQL5.6如果开启GTID模式，需要在my.cnf中加入以下几个参数：


①log-bin=mysql-bin

②binlog_format=row

③log_slave_updates=1

④gtid_mode=ON

⑤enforce_gtid_consistency=ON


Warning:警告这里的一些参数不是动态参数，也就是需要重启mysql才能生效。



Part2:环境

[root@HE1 ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.16-log MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select version();
+------------+
| version()  |
+------------+
| 5.7.16-log |
+------------+
1 row in set (0.00 sec)
mysql> show global variables like 'log_slave%';
+-------------------+-------+
| Variable_name     | Value |
+-------------------+-------+
| log_slave_updates | OFF   |
+-------------------+-------+
1 row in set (0.00 sec)


MySQL5.6开启GTID需要开启log_slave_updates参数，否则启动报错，而5.7不在需要开启该参数。


实战

Part1:搭建传统复制模式

本文环境HE1为从，HE3为主库


[root@HE1 ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.16-log MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.250
                  Master_User: mysync
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 1694
               Relay_Log_File: HE1-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000002
             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: 1694
              Relay_Log_Space: 525
              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: 1250
                  Master_UUID: 82b160c7-9a8f-11e6-8412-000c29c6361d
             Master_Info_File: /data/mysql/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: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)


Part2:传统复制模式切换为GTID

①主库从库都需执行以下命令

mysql> set global gtid_mode='OFF_PERMISSIVE';
Query OK, 0 rows affected (0.01 sec)
mysql> set global gtid_mode='ON_PERMISSIVE';
Query OK, 0 rows affected (0.01 sec)
mysql> set global enforce_gtid_consistency=ON;
Query OK, 0 rows affected (0.00 sec)
mysql> set global gtid_mode='ON';
Query OK, 0 rows affected (0.00 sec)


②主库插数从库执行

mysql> show master status;
+------------------+----------+--------------+------------------+----------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                      |
+------------------+----------+--------------+------------------+----------------------------------------+
| mysql-bin.000005 |      154 |              |                  | 82b160c7-9a8f-11e6-8412-000c29c6361d:1 |
+------------------+----------+--------------+------------------+----------------------------------------+
1 row in set (0.00 sec)

可以看到gtid_set下面有数了，这说明已经开启了gtid模式



Part3:GTID变更为传统模式

mysql> stop slave;-----从库执行
Query OK, 0 rows affected (0.00 sec)

mysql> set global gtid_mode='ON_PERMISSIVE';
Query OK, 0 rows affected (0.00 sec)

mysql> set global gtid_mode='OFF_PERMISSIVE';
Query OK, 0 rows affected (0.01 sec)

mysql> CHANGE MASTER TO MASTER_AUTO_POSITION=0;
Query OK, 0 rows affected (0.05 sec)

mysql> set global gtid_mode='OFF';
Query OK, 0 rows affected (0.00 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%gtid%';
+----------------------------------+----------------------------------------+
| Variable_name                    | Value                                  |
+----------------------------------+----------------------------------------+
| binlog_gtid_simple_recovery      | ON                                     |
| enforce_gtid_consistency         | ON                                     |
| gtid_executed_compression_period | 1000                                   |
| gtid_mode                        | OFF                                    |
| gtid_next                        | AUTOMATIC                              |
| gtid_owned                       |                                        |
| gtid_purged                      | 82b160c7-9a8f-11e6-8412-000c29c6361d:1 |
| session_track_gtids              | OFF                                    |
+----------------------------------+----------------------------------------+
8 rows in set (0.01 sec)


可以看到这里GTID模式已经关了，下面再次开启GTID模式来观察id的变化

mysql> set global gtid_mode='OFF_PERMISSIVE';
Query OK, 0 rows affected (0.01 sec)
mysql> set global gtid_mode='ON_PERMISSIVE';
Query OK, 0 rows affected (0.01 sec)
mysql> set global enforce_gtid_consistency=ON;
Query OK, 0 rows affected (0.00 sec)
mysql> set global gtid_mode='ON';
Query OK, 0 rows affected (0.01 sec)
mysql> 
mysql> 
mysql> show variables like '%gtid%';
+----------------------------------+----------------------------------------+
| Variable_name                    | Value                                  |
+----------------------------------+----------------------------------------+
| binlog_gtid_simple_recovery      | ON                                     |
| enforce_gtid_consistency         | ON                                     |
| gtid_executed_compression_period | 1000                                   |
| gtid_mode                        | ON                                     |
| gtid_next                        | AUTOMATIC                              |
| gtid_owned                       |                                        |
| gtid_purged                      | 82b160c7-9a8f-11e6-8412-000c29c6361d:1 |
| session_track_gtids              | OFF                                    |
+----------------------------------+----------------------------------------+
8 rows in set (0.00 sec)

主库做操作，从库执行如下命令会看到gtid_set的值在变化
mysql> show master status;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000011 |      154 |              |                  | 82b160c7-9a8f-11e6-8412-000c29c6361d:1-2 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

mysql> show master status;
+------------------+----------+--------------+------------------+------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000011 |      154 |              |                  | 82b160c7-9a8f-11e6-8412-000c29c6361d:1-3 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

——总结——

MySQL5.7开启/关闭GTID，不用重启mysql，这大大提高了GTID的易用性。由于笔者的水平有限，编写时间也很仓促，文中难免会出现一些错误或者不准确的地方，不妥之处恳请读者批评指正。