MySQL基于GTID的集群复制

发布时间：2023-08-03 15:02:17 所属栏目：MySql教程来源：

导读：MySQL基于GTID的主从复制

1、什么是GTID？

1、全局唯一，一个事务对应一个GTID

2、替代传统的binlog+pos复制；使用master_auto_position=1自动匹配GTID断点进行复制

3、MySQL5.6开始支持

4、在传

MySQL基于GTID的主从复制

1、什么是GTID？

1、全局唯一，一个事务对应一个GTID

2、替代传统的binlog+pos复制；使用master_auto_position=1自动匹配GTID断点进行复制

3、MySQL5.6开始支持

4、在传统的主从复制中，slave端不用开启binlog；但是在GTID主从复制中，必须开启binlog

5、slave端在接受master的binlog时，会校验GTID值

6、为了保证主从数据的一致性，多线程同时执行一个GTID

2、组成

Master_UUID:序列号

举例：

ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5

ceb0ca3d-8366-11e8-ad2b-000c298b7c9a其实就是master的uuid值；1-5是序列号，每次一个事务完成都会自增1，也就是说下一次为1-6。

3、工作原理

1、master更新数据时，会在事务前产生GTID，一同记录到binlog日志中。

2、slave端的i/o 线程将变更的binlog，写入到本地的relay log中。

3、sql线程从relay log中获取GTID，然后对比slave端的binlog是否有记录。

4、如果有记录，说明该GTID的事务已经执行，slave会忽略。

5、如果没有记录，slave就会从relay log中执行该GTID的事务，并记录到binlog。

6、在解析过程中会判断是否有主键，如果没有就用二级索引，如果没有就用全部扫描

4、GTID主从配置

版本：MySQL5.7

配置master

vim /etc/my.cnf

[client]

socket=/usr/local/mysql/mysql.sock

[mysqld]

basedir=/usr/local/mysql

datadir=/usr/local/mysql/data

user=mysql

pid-file=/usr/local/mysql/data/mysqld.pid

log-error=/usr/local/mysql/data/mysql.err

socket=/usr/local/mysql/mysql.sock

port=3306

server-id=1

gtid-mode=ON

enforce-gtid-consistency=ON

server-id=1

binlog_format=row

log-bin=/usr/local/mysql/data/mysql-bin

systemctl restart mysqld

firewall-cmd --add-port=3306/tcp --permanent

firewall-cmd --reload

配置slave

vim /etc/my.cnf

[client]

socket=/usr/local/mysql/mysql.sock

[mysqld]

basedir=/usr/local/mysql

datadir=/usr/local/mysql/data

user=mysql

pid-file=/usr/local/mysql/data/mysqld.pid

log-error=/usr/local/mysql/data/mysql.err

socket=/usr/local/mysql/mysql.sock

port=3306

server-id=2

gtid-mode=ON

enforce-gtid-consistency=ON

server-id=2

binlog_format=ROW

log-bin=/usr/local/mysql/data/mysql-bin

log_slave_updates=ON

skip-slave-start=1

systemctl restart mysqld

firewall-cmd --add-port=3306/tcp --permanent

firewall-cmd --reload

master授权配置

mysql -uroot -p

mysql> grant replication slave on *.* to 'rep'@'10.0.0.%' identified by '123';

mysql> flush privileges;

slave配置同步

mysql -uroot -p

mysql> change master to master_host='10.0.0.132', master_user='rep',master_password='123',master_port=3306,master_auto_position=1;

mysql> start slave;

查看slave的状态

mysql> show slave status\G;

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

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 10.0.0.132

                  Master_User: rep

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: mysql-bin.000003

          Read_Master_Log_Pos: 635

               Relay_Log_File: slave-relay-bin.000005

                Relay_Log_Pos: 848

        Relay_Master_Log_File: mysql-bin.000003

             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: 635

              Relay_Log_Space: 1308

              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: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a

             Master_Info_File: /usr/local/mysql/data/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: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-4

            Executed_Gtid_Set: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-4

                Auto_Position: 1

         Replicate_Rewrite_DB:

                 Channel_Name:

           Master_TLS_Version:

1 row in set (0.00 sec)

出现这两个yes表示同步成功

通过slave的状态信息，可以看到GTID的值、Matser_UUID等信息

查看master状态

mysql> show master status;

+------------------+----------+--------------+------------------+------------------------------------------+

| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |

+------------------+----------+--------------+------------------+------------------------------------------+

| mysql-bin.000003 |      635 |              |                  | ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-4 |

+------------------+----------+--------------+------------------+------------------------------------------+

1 row in set (0.00 sec)

注意对比slave端，Executed_Gtid_Set的值应该是一样的。

5、验证主从

master上

mysql> create database test01;

Query OK, 1 row affected (0.00 sec)

mysql> show master status;

+------------------+----------+--------------+------------------+------------------------------------------+

| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |

+------------------+----------+--------------+------------------+------------------------------------------+

| mysql-bin.000003 |      800 |              |               | ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5 |

+------------------+----------+--------------+------------------+------------------------------------------+

1 row in set (0.00 sec)

slave上

mysql> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| sys                |

| test01             |

+--------------------+

5 rows in set (0.07 sec)

mysql> show slave status\G;

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

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 10.0.0.132

                  Master_User: rep

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: mysql-bin.000003

          Read_Master_Log_Pos: 800

               Relay_Log_File: slave-relay-bin.000005

                Relay_Log_Pos: 1013

        Relay_Master_Log_File: mysql-bin.000003

             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: 800

              Relay_Log_Space: 1473

              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: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a

             Master_Info_File: /usr/local/mysql/data/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: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5

            Executed_Gtid_Set: ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5

                Auto_Position: 1

         Replicate_Rewrite_DB:

                 Channel_Name:

           Master_TLS_Version:

1 row in set (0.00 sec)

需要注意的是，GTID的值在完成一次事务后，变成了ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5（自增1）

6、排障

思路

a、确保master开放3306端口

b、最好关闭selinux

c、master上授权同步，slave上change master命令指定master的信息不要写错

d、UUID问题

如果你出现了上图所示的问题，表示你的master和slave的UUID是一样的，一般这种情况多出现于克隆虚拟机

解决办法：

找到slave上的MySQL数据目录下的auto.cnf文件（这个文件其实是自动生成的mysql服务器的UUID值），将它删除，然后重启MySQL，然后MySQL会重新生成一个UUID。然后停掉slave，重新开启就可以了（我的mysql的数据目录是在/usr/local/mysql/data下，详情查看my.cnf配置文件）

cd /usr/local/mysql/data

rm -f auto.cnf

systemctl restart mysql

[root@slave data]# cat auto.cnf

[auto]

server-uuid=020c7f26-be57-11e8-8e2d-000c29b63bad

通过cat命令查看该文件，发现UUID已经改变

mysql -uroot -p

mysql> stop slave;

mysql> start slave;

e、总结

排障过程中，注意需要停掉slave，做完修改之后在开启，否则你的修改可能是不会生效的。

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