mysql的GTID同步

2023-09-01 17:10 由兜里有个草莓发表于 #数据库

什么是GTID？

GTID (Global Transaction ID) 是对于一个已提交事务的编号，并且是一个全局唯一的编号。 GTID 实际上是由UUID+TID 组成的。
其中 UUID 是一个 MySQL 实例的唯一标识。TID代表了该实例上已经提交的事务数量，并且随着事务提交单调递增。

下面是一个GTID的具体形式：03a1eb63-c21a-11ec-b07f-000c2987bea6:1-25，冒号分割前边为UUID，后边为TID。

GTID 集合可以包含来自多个 MySQL 实例的事务，它们之间用逗号分隔。

GTID的工作原理

①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。
②binlog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。
③sql线程从relay log中获取GTID，然后对比slave端的binlog是否有该GTID。
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。
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。

数据库角色 IP 系统与MySQL版本有无数据
主数据库 192.168.121.164 RHEL7 MySQL5.7 无数据
从数据库 192.168.121.133 RHEL7 MySQL5.7 无数据

mysql> grant replication slave on \*.* to 'slave'@'192.168.121.%' identified by 'MySql@123';
Query OK, 0 rows affected, 1 warning (0.00 sec)

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

mysql> exit
Bye

配置主库文件

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
port=3306
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
skip-name-resolve
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
skip-name-resolve

log-bin=mysql-bin #开启二进制日志
server-id=1 #服务器ID，必须唯一
gtid-mode=on #开启gtid模式
enforce-gtid-consistency=on #强制gtid一致性，开启后对特定的create table不支持
binlog-format=row #默认为mixed混合模式，更改成row复制，为了数据一致性
log-slave-updates=1 #从库binlog记录主库同步的操作日志
skip-slave-start=1 #跳过slave复制线程
binlog-ignore-db=mysql

然后重启一下数据库

[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# systemctl status mysqld

查看GTID模式状态

[root@localhost ~]# mysql -uroot -pMySql@123 -e '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 | |
| session_track_gtids | OFF |
+----------------------------------+-----------+

配置从库文件

[root@localhost ~]# vim /etc/my.cnf
[mysqld]
port=3306
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
skip-name-resolve

log-bin=mysql-bin
server-id=2
gtid-mode=on
enforce-gtid-consistency=on
binlog-format=row
log-slave-updates=1
skip-slave-start=1

然后重启一下数据库

[root@localhost ~]# systemctl restart mysqld
[root@localhost ~]# systemctl status mysqld

查看GTID模式状态

[root@localhost ~]# mysql -uroot -pMySql@123 -e 'show variables like "%GTID%";'

开启主从同步

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

mysql> change master to
master_host='192.168.121.164',
master_user='slave',
master_password='MySql@123',
master_auto_position=1;

使用GTID方式同步的时候，必须指定master_auto_position=1
GTID使用master_auto_position=1代替了基于binlog和position号的主从同步方式,更便于主从同步的搭建

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.11
Master_User: Jaking
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 154
Relay_Log_File: server12-relay-bin.000002
Relay_Log_Pos: 367
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: 154
Relay_Log_Space: 577
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: 11
Master_UUID: 03a1eb63-c21a-11ec-b07f-000c2987bea6
Master_Info_File: /var/lib/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: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

然后进行数据测试

create table aa(nid int,stuname char(15),sex int);

insert into aa value (2001,'tom',1),(2002,'mary',0),(2003,'cak',1);

select * from aa;

然后去从库查看数据

发现库已经有了，到这里已经可以高兴了

当然还是要看下表了，结果还是令人满意的

这时候我们可以看下两个库的状态

查看主库状态

mysql> show master status;
+------------------+----------+--------------+------------------+------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000002 | 1620 | | | 03a1eb63-c21a-11ec-b07f-000c2987bea6:1-6 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

查看从库状态

mysql> show master status;
+------------------+----------+--------------+------------------+------------------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+------------------------------------------+
| mysql-bin.000002 | 1584 | | | 03a1eb63-c21a-11ec-b07f-000c2987bea6:1-6 |
+------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

到这里就完成辣

还有可以测试一下从库停机后，主库仍在写入数据，从库恢复后能否自动同步数据

从库停掉主从同步

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

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.10.11
Master_User: Jaking
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 1620
Relay_Log_File: server12-relay-bin.000002
Relay_Log_Pos: 1833
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: No
Slave_SQL_Running: No
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: 1620
Relay_Log_Space: 2043
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: NULL
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: 11
Master_UUID: 03a1eb63-c21a-11ec-b07f-000c2987bea6
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set: 03a1eb63-c21a-11ec-b07f-000c2987bea6:1-6
Executed_Gtid_Set: 03a1eb63-c21a-11ec-b07f-000c2987bea6:1-6
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

然后去主库添加数据

查看从库

是没有同步信息过来的，因为我们没有开启同步

然后我们开启同步

所有测试就完成了。

祝大家都能成功。