MySQL之GTID主从配置

GTID原理：

当一个事务在主库端执行并提交时，产生GTID，一同记录到binlog日志中。
binlog传输到slave,并存储到slave的relaylog后，读取这个GTID的这个值设置gtid_next变量，即告诉Slave，下一个要执行的GTID值。
sql线程从relay log中获取GTID，然后对比slave端的binlog是否有该GTID。
如果有记录，说明该GTID的事务已经执行，slave会忽略。
如果没有记录，slave就会执行该GTID事务，并记录该GTID到自身的binlog，
在读取执行事务前会先检查其他session持有该GTID，确保不被重复执行。
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。

环境要求：

数据库角色	IP	系统版本与应用	有无数据
主数据库	192.168.225.128	redhat7 mysql-5.7	无数据
从数据库	192.168.225.129	redhat7 mysql-5.7	无数据

修改主数据库配置文件

[root@hxdserver ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve

#GTID:
server-id=128          //服务器id
gtid-mode=on          //开启GTID模式
enforce-gtid-consistency=on      //强制gtid一致性，开启后对于特定create table不被支持

#binlog
log-bin=master-binlog
log-slave-updates=1
binlog-format=row                       //强烈建议，其他格式可能造成数据不一致

#relay log
skip-slave-start=1

修改从数据库配置文件

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve

#GTID
gtid-mode=on
enforce-gtid-consistency=on
server-id=129

#binglog
log-bin=slave-binglog
log-slave-updates=1
binlog-format=row

#relay log
skip-slave-start=1

• 在主数据库里创建一个同步账号授权给从库使用

mysql> create user 'repl'@'192.168.225.129' identified by 'repl123.';
Query OK, 0 rows affected (0.01 sec)

mysql> grant replication slave on *.* to 'repl'@'192.168.225.129';
Query OK, 0 rows affected (0.00 sec)

mysql>  flush privileges;
Query OK, 0 rows affected (0.00 sec)

192.168.225.129(从库)

mysql> CHANGE MASTER TO
    -> MASTER_HOST='192.168.225.128',
    -> MASTER_USER='repl',
    -> MASTER_PASSWORD='repl123.',
    -> MASTER_PORT=3306,
    -> MASTER_AUTO_POSITION = 1;
Query OK, 0 rows affected, 2 warnings (0.06 sec)

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

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.225.128
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-binlog.000002
          Read_Master_Log_Pos: 1019
               Relay_Log_File: localhost-relay-bin.000002
                Relay_Log_Pos: 1240
        Relay_Master_Log_File: master-binlog.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: 1019
              Relay_Log_Space: 1451
              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: 128
                  Master_UUID: 85620474-e669-11e8-bdf5-000c294b7cb8
             Master_Info_File: /opt/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: 85620474-e669-11e8-bdf5-000c294b7cb8:1-4
            Executed_Gtid_Set: 85620474-e669-11e8-bdf5-000c294b7cb8:1-4
                Auto_Position: 1
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

验证：

在主库上创建一个库
mysql> create database dubai;
Query OK, 1 row affected (0.00 sec)

在从库上查看
[root@localhost ~]# mysql -uroot -phxd123456. -e'show databases;'
mysql: [Warning] Using a password on the command line interface can be insecure.
+--------------------+
| Database           |
+--------------------+
| information_schema |
| dubai              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
[root@localhost ~]# 

同步成功