前几天，有读者在后盾留言问我可有基于Gtid的Mysql主从同步的文章，我记得历史文章应该有提及过，也有可能是只是提及，可能没有具体的过程介绍，所以，明天，民工哥就给大家安顿一波。
什么是GTID？
- 1、全局惟一，一个事务对应一个GTID
- 2、代替传统的binlog+pos复制；应用master_auto_position=1主动匹配GTID断点进行复制
- 3、MySQL5.6开始反对
- 4、在传统的主从复制中，slave端不必开启binlog；然而在GTID主从复制中，必须开启binlog
- 5、slave端在承受master的binlog时，会校验GTID值
- 6、为了保障主从数据的一致性，多线程同时执行一个GTID
组成
Master_UUID:序列号举例：ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5ceb0ca3d-8366-11e8-ad2b-000c298b7c9a其实就是master的uuid值；1-5是序列号，每次一个事务实现都会自增1，也就是说下一次为1-6。工作原理
- 1、master更新数据时，会在事务前产生GTID，一起记录到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，而后比照slave端的binlog是否有记录。
- 4、如果有记录，阐明该GTID的事务曾经执行，slave会疏忽。
- 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，如果没有就用全副扫描
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-binsystemctl restart mysqldfirewall-cmd --add-port=3306/tcp --permanentfirewall-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=1systemctl restart mysqldfirewall-cmd --add-port=3306/tcp --permanentfirewall-cmd --reloadmaster受权配置
mysql -uroot -pmysql> grant replication slave on *.* to 'rep'@'10.0.0.%' identified by '123';mysql> flush privileges;slave配置同步
mysql -uroot -pmysql> 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: 0Master_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)呈现这两个yes示意同步胜利
通过slave的状态信息，能够看到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)留神比照slave端，Executed\_Gtid\_Set的值应该是一样的。
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: 0Master_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)须要留神的是，GTID的值在实现一次事务后，变成了ceb0ca3d-8366-11e8-ad2b-000c298b7c9a:1-5（自增1）
排障
思路
- a、确保master凋谢3306端口
- b、最好敞开selinux
- c、master上受权同步，slave上change master命令指定master的信息不要写错
- d、UUID问题
如果你呈现了上图所示的问题，示意你的master和slave的UUID是一样的，个别这种状况多呈现于克隆虚拟机
解决办法：
找到slave上的MySQL数据目录下的auto.cnf文件（这个文件其实是主动生成的mysql服务器的UUID值），将它删除，而后重启MySQL，而后MySQL会从新生成一个UUID。而后停掉slave，从新开启就能够了（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/datarm -f auto.cnfsystemctl 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曾经扭转
mysql -uroot -pmysql> stop slave;mysql> start slave;总结
排障过程中，留神须要停掉slave，做完批改之后在开启，否则你的批改可能是不会失效的。
起源：https://blog.51cto.com/u_1343...