mysql学习--binlog与gtid主从同步

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基础环境

基于centOS7-MySQL8.0.35版本

我们先准备一台主服务器两台从服务器来实现我们主从同步的诉求

Master：192.168.75.142

slave1:192.168.75.143

slave：192.168.75.145

binlog主从同步

主库配置

#我们需要在主从库中都需要添加server_id，每个库的server_id都不唯一
[root@localhost ~]# tail -1 /etc/my.cnf
server_id=1
#重启mysql服务让配置分件生效
[root@localhost ~]# systemctl restart mysqld
#备份：
[root@localhost ~]# mysqldump --opt -B -u root -p school school1> school.sql
#授权用户：
mysql> create user rep@'192.168.75.%' identified with mysql_native_password by 'Mhn@2001';
mysql> grant replication slave on *.* to rep@'192.168.75.%';

从库配置

[root@localhost ~]# tail -1 /etc/my.cnf
server_id=2
[root@localhost ~]# systemctl restart mysqld[root@localhost ~]# tail -1 /etc/my.cnf
server_id=3
[root@localhost ~]# systemctl restart mysqld#还原主库备份，到从服务器家目录下：
scp db.sql 192.168.75.143:/root/
scp db.sql 192.168.75.145:/root/#在两台从主机上将复制的备份文件导入数据库
mysql -uroot -pMysql@123 < school.sql#主库查看
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |      679 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)从库配置
change master to
master_host='192.168.75.42',
master_user='rep',
master_password='Mhn@2001',
master_log_file='mysql-bin.000001',
master_log_pos=679,
get_master_public_key=1;

mysql> show slave status \G
*************************** 1. row ***************************Slave_IO_State: Waiting for source to send eventMaster_Host: 192.168.75.142Master_User: repMaster_Port: 3306Connect_Retry: 60Master_Log_File: binlog.000002Read_Master_Log_Pos: 694Relay_Log_File: localhost-relay-bin.000002Relay_Log_Pos: 323Relay_Master_Log_File: binlog.000002Slave_IO_Running: YesSlave_SQL_Running: Yes

从这里可以查看到状态没有问题可以进行主从同步

其他可选配置

#[可选] 0（默认）表示读写（主机），1表示只读（从机）
read-only=0
#设置日志文件保留的时长，单位是秒
binlog_expire_logs_seconds=6000
#控制单个二进制日志大小。此参数的最大和默认值是1GB
max_binlog_size=200M
#[可选]设置不要复制的数据库
binlog-ignore-db=test
#[可选]设置需要复制的数据库,默认全部记录。
binlog-do-db=需要复制的主数据库名字
#[可选]设置binlog格式
binlog_format=STATEMENT

素材

数据库备份，数据库为school，素材如下1.创建student和score表CREATE  TABLE  student (
id  INT(10)  NOT NULL  UNIQUE  PRIMARY KEY  ,
name  VARCHAR(20)  NOT NULL ,
sex  VARCHAR(4)  ,
birth  YEAR,
department  VARCHAR(20) ,
address  VARCHAR(50) 
);创建score表。SQL代码如下：CREATE  TABLE  score (
id  INT(10)  NOT NULL  UNIQUE  PRIMARY KEY  AUTO_INCREMENT ,
stu_id  INT(10)  NOT NULL ,
c_name  VARCHAR(20) ,
grade  INT(10)
);2.为student表和score表增加记录向student表插入记录的INSERT语句如下：INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');
INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');
INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');向score表插入记录的INSERT语句如下：
INSERT INTO score VALUES(NULL,901, '计算机',98);
INSERT INTO score VALUES(NULL,901, '英语', 80);
INSERT INTO score VALUES(NULL,902, '计算机',65);
INSERT INTO score VALUES(NULL,902, '中文',88);
INSERT INTO score VALUES(NULL,903, '中文',95);
INSERT INTO score VALUES(NULL,904, '计算机',70);
INSERT INTO score VALUES(NULL,904, '英语',92);
INSERT INTO score VALUES(NULL,905, '英语',94);
INSERT INTO score VALUES(NULL,906, '计算机',90);
INSERT INTO score VALUES(NULL,906, '英语',85);

create database school;
use school;
CREATE TABLE `Student` (`Sno` int(10) NOT NULL COMMENT '学号',  `Sname` varchar(16) NOT NULL COMMENT '姓名',`Ssex` char(2) NOT NULL COMMENT '性别',  `Sage` tinyint(2) NOT NULL DEFAULT '0' COMMENT '学生年龄',`Sdept` varchar(16) DEFAULT 'NULL' COMMENT '学生所在系别',  PRIMARY KEY (`Sno`)) ;
INSERT INTO `Student` VALUES (1, '陆亚', '男', 24, '计算机网络'),(2, 'tom', '男', 26, '英语'),(3, '张阳', '男', 21, '物流管理'), (4, 'alex', '女', 22, '电子商务');

gtid主从同步

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。

2.binlog传输到slave，并存储到salve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。

3.sql线程从relaylog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会执行该GTID事务，并记录到该GTID到自身的binlog，在读取该事务前会检查其他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，如果有就用全部扫描。

主库配置

主库配置
[root@localhost ~]# vim /etc/my.cnf
server_id=1  
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
log-bin=mysql-bin    #开启二进制日志
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#重启服务
[root@localhost ~]# systemctl restart mysqld
#查看服务状态
[root@localhost ~]# systemctl status mysqld
● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 四 2024-02-29 11:04:01 CST; 37min agoDocs: man:mysqld(8)http://dev.mysql.com/doc/refman/en/using-systemd.htmlProcess: 3740 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 3770 (mysqld)Status: "Server is operational"Tasks: 40CGroup: /system.slice/mysqld.service└─3770 /usr/sbin/mysqld[root@localhost ~]# mysql -uroot -pMysql@123
mysql> show variables like '%gtid%';
+----------------------------------+------------------------------------------+
| Variable_name                    | Value                                    |
+----------------------------------+------------------------------------------+
| binlog_gtid_simple_recovery      | ON                                       |
| enforce_gtid_consistency         | ON                                       |
| gtid_executed                    | ff800e4d-d478-11ee-83a4-000c29b35fbd:1-8 |
| gtid_executed_compression_period | 0                                        |
| gtid_mode                        | ON                                       |
| gtid_next                        | AUTOMATIC                                |
| gtid_owned                       |                                          |
| gtid_purged                      |                                          |
| session_track_gtids              | OFF                                      |
+----------------------------------+------------------------------------------+
9 rows in set (0.01 sec)

从库配置

#slave1
server_id=2
gtid_mode=ON
enforce-gtid-consistency=ON
log-bin=mysql-bin
log-slave-updates=1
skip-slave-start=1
mysql> show variables like '%gtid%';
+----------------------------------+------------------------------------------+
| Variable_name                    | Value                                    |
+----------------------------------+------------------------------------------+
| binlog_gtid_simple_recovery      | ON                                       |
| enforce_gtid_consistency         | ON                                       |
| gtid_executed                    | ff800e4d-d478-11ee-83a4-000c29b35fbd:1-8 |
| gtid_executed_compression_period | 0                                        |
| gtid_mode                        | ON                                       |
| gtid_next                        | AUTOMATIC                                |
| gtid_owned                       |                                          |
| gtid_purged                      |                                          |
| session_track_gtids              | OFF                                      |
+----------------------------------+------------------------------------------+
9 rows in set (0.00 sec)#slave2
server_id=3
gtid_mode=ON
enforce-gtid-consistency=ON
log-bin=mysql-bin
log-slave-updates=1
skip-slave-start=1
mysql> show variables like '%gtid%';
+----------------------------------+------------------------------------------+
| Variable_name                    | Value                                    |
+----------------------------------+------------------------------------------+
| binlog_gtid_simple_recovery      | ON                                       |
| enforce_gtid_consistency         | ON                                       |
| gtid_executed                    | ff800e4d-d478-11ee-83a4-000c29b35fbd:1-8 |
| gtid_executed_compression_period | 0                                        |
| gtid_mode                        | ON                                       |
| gtid_next                        | AUTOMATIC                                |
| gtid_owned                       |                                          |
| gtid_purged                      |                                          |
| session_track_gtids              | OFF                                      |
+----------------------------------+------------------------------------------+
9 rows in set (0.00 sec)

开启主从同步

#主库
mysql> stop slave;
Query OK, 0 rows affected, 2 warnings (0.01 sec)mysql>  create user rep@'192.168.75.%' identified with mysql_native_password by 'Mhn@2001';
Query OK, 0 rows affected (0.04 sec)mysql> grant replication slave on *.* to rep@'192.168.75.%';
Query OK, 0 rows affected (0.00 sec)

#从库，两个都一样
mysql> CHANGE MASTER TO-> MASTER_HOST = '192.168.75.142',-> MASTER_USER = 'rep',-> MASTER_PASSWORD = 'Mhn@2001',-> MASTER_AUTO_POSITION = 1;
Query OK, 0 rows affected, 7 warnings (0.01 sec)

#主库建立数据库
mysql> create database book;
Query OK, 1 row affected (0.00 sec)mysql> use book;
Database changed
mysql> CREATE TABLE books (name char(66),price int,pages int);
'80','666');
INSERT INTO books(name,price,pages) VALUES('Artificial Intelligence','166','666');Query OK, 0 rows affected (0.02 sec)mysql> INSERT INTO books(name,price,pages) VALUES('Linux','30','666');
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO books(name,price,pages) VALUES('Cloud Computing','60','666');
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO books(name,price,pages) VALUES('Operation System','80','666');
Query OK, 1 row affected (0.00 sec)mysql> INSERT INTO books(name,price,pages) VALUES('Artificial Intelligence','166','666');
Query OK, 1 row affected (0.00 sec)mysql> select * from books;
+-------------------------+-------+-------+
| name                    | price | pages |
+-------------------------+-------+-------+
| Linux                   |    30 |   666 |
| Cloud Computing         |    60 |   666 |
| Operation System        |    80 |   666 |
| Artificial Intelligence |   166 |   666 |
+-------------------------+-------+-------+
4 rows in set (0.00 sec)

#从库的状态查看
#slave1
mysql> show slave status \G
*************************** 1. row ***************************Slave_IO_State: Waiting for source to send eventMaster_Host: 192.168.75.142Master_User: repMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-bin.000001Read_Master_Log_Pos: 680Relay_Log_File: localhost-relay-bin.000002Relay_Log_Pos: 896Relay_Master_Log_File: mysql-bin.000001Slave_IO_Running: YesSlave_SQL_Running: Yes
#slave2
mysql> show slave status \G
*************************** 1. row ***************************Slave_IO_State: Waiting for source to send eventMaster_Host: 192.168.75.142Master_User: repMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-bin.000001Read_Master_Log_Pos: 680Relay_Log_File: localhost-relay-bin.000002Relay_Log_Pos: 896Relay_Master_Log_File: mysql-bin.000001Slave_IO_Running: YesSlave_SQL_Running: Yes

#从库查看
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| book               |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.01 sec)mysql> use book;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -ADatabase changed
mysql> show tables;
+----------------+
| Tables_in_book |
+----------------+
| books          |
+----------------+
1 row in set (0.00 sec)mysql> select * from book.books;
+-------------------------+-------+-------+
| name                    | price | pages |
+-------------------------+-------+-------+
| Linux                   |    30 |   666 |
| Cloud Computing         |    60 |   666 |
| Operation System        |    80 |   666 |
| Artificial Intelligence |   166 |   666 |
+-------------------------+-------+-------+
4 rows in set (0.00 sec)

主库

从库1

从库2

可以看到最后的gtid值都一样这就说明我们配置完成。

解决问题

在gtid配置中如果出现 Last_IO_Error: Error connecting to source 'root@192.168.75.142:3306'. This was attempt 1/86400, with a delay of 60 seconds between attempts. Message: Host '192.168.75.143' is not allowed to connect to this MySQL server

可以尝试更改一下主库的mysql> create user rep@'192.168.75.%' identified with mysql_native_password by 'Mhn@2001';
Query OK, 0 rows affected (0.04 sec)

首先我们需要将所有的库进行stop slave；操作，然后进行操作，修改完成后再次开启就可以使用。

在遇到问题可以使用翻译和查询日志来进行查看

如果我们是使用一段时间mysql后才配置的gtid主从同步需要注意gtid值需要开始的位置，不能从1开始

需要注入空事务，从而解决起始位置相同

stop slave;
set gtid_next='gtid值:开始位置';
begin;commit;
set gtid_next='AUTOMATIC';