MySQL5.7在线开启/关闭GTID

影者东升

　　

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。