拓扑结构：（一主多从）
Mysql-master01 (192.168.43.123)
Mysql-slave01 (192.168.43.124)
Mysql-slave02 (192.168.43.125)
版本信息：
OS版本 ： CentOS release 6.10 最小化安装
Mysql版本： mysql-5.7.31-1.el6.x86_64.rpm-bundle.tar
一、系统调整（测试）
适用范围：所有服务器
1.关闭防火墙
2.修改/etc/selinux/config关闭selinux
3.其他工具软件的安装 vim openssh-* net-tools 等
二、Mysql的安装
适用范围：所有服务器
1.安装
[root@localhost opt]# tar -xf mysql-5.7.31-1.el6.x86_64.rpm-bundle.tar
[root@localhost opt]# yum install mysql-community-* -y
2.root密码调整
[root@localhost opt]# /etc/init.d/mysqld start
Initializing MySQL database: [ OK ]
Starting mysqld: [ OK ]
[root@localhost opt]#
mysql> alter user 'root'@'localhost' identified by 'Test.123';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
三、配置主从复制
1.配置调整
主服务器配置：
mysql> system cat /etc/my.cnf
[mysqld]
log-bin=/var/log/mysql/mysql-bin
server-id=1
innodb_flush_log_at_trx_commit = 1
sync_binlog = 1
gtid_mode=ON
enforce_gtid_consistency=1
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
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION
default-storage-engine = INNODB
character-set-server = utf8
collation-server = utf8_general_ci
[client]
default-character-set = utf8
从服务器配置：
[root@localhost mysql]# cat /etc/my.cnf
[mysqld]
log-bin=/var/log/mysql/mysql-bin
server-id=2
innodb_flush_log_at_trx_commit = 1
sync_binlog = 1
gtid_mode=ON
enforce_gtid_consistency=1
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
default-storage-engine = INNODB
character-set-server = utf8
collation-server = utf8_general_ci
[client]
default-character-set = utf8
[root@localhost opt]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
2.复制用户创建（主服务器配置）
mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%' identified by 'Test.123';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql>
从服务器测试一下：
[root@localhost opt]# mysql -urepl -p'Test.123' -h 192.168.43.123
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
3.将从服务器加入新服务器（2台从服务器）
mysql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)
mysql> CHANGE MASTER TO MASTER_HOST='192.168.43.123', MASTER_USER='repl', MASTER_PASSWORD='Test.123', MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.03 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: 192.168.43.123
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 154
Relay_Log_File: localhost-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: 578
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: 04baf52c-e083-11ea-9564-000c29298862
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)
ERROR:
No query specified
mysql> unlock tables;
Query OK, 0 rows affected (0.01 sec)
四、测试
主服务器操作：
mysql> create table test(id int primary key ,name varchar(20));
Query OK, 0 rows affected (0.03 sec)
mysql> insert into test(id,name) values(1,'A'),(2,'B'),(3,'C');
Query OK, 3 rows affected (0.03 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql>
mysql> select * from test;
+----+------+
| id | name |
+----+------+
| 1 | A |
| 2 | B |
| 3 | C |
+----+------+
3 rows in set (0.00 sec)
从服务器查询：
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.43.123
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 781
Relay_Log_File: localhost-relay-bin.000002
Relay_Log_Pos: 994
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: 781
Relay_Log_Space: 1205
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: 04baf52c-e083-11ea-9564-000c29298862
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: 04baf52c-e083-11ea-9564-000c29298862:1-3
Executed_Gtid_Set: 04baf52c-e083-11ea-9564-000c29298862:1-3
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| testrep |
+--------------------+
6 rows in set (0.00 sec)
mysql> use test
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from test;
+----+------+
| id | name |
+----+------+
| 1 | A |
| 2 | B |
| 3 | C |
+----+------+
3 rows in set (0.00 sec)
五、日志分析
[root@localhost mysql]# ls
mysql-bin.000001 mysql-bin.000002 mysql-bin.index
说明：mysql-bin.000001为未开启GTID的binlog，mysql-bin.000002为开启GTID的binlog
[root@localhost mysql]# mysqlbinlog --no-defaults --base64-output=decode-rows -v mysql-bin.000001 --result-file=1.sql
[root@localhost mysql]# mysqlbinlog --no-defaults --base64-output=decode-rows -v mysql-bin.000002 --result-file=2.sql
[root@localhost mysql]# vim 2.sql
[root@localhost mysql]# vim 1.sql
[root@localhost mysql]# cat 1.sql | grep 'SET @@SESSION.GTID_NEXT='
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
[root@localhost mysql]# cat 2.sql | grep 'SET @@SESSION.GTID_NEXT='
SET @@SESSION.GTID_NEXT= '04baf52c-e083-11ea-9564-000c29298862:1'/*!*/;
SET @@SESSION.GTID_NEXT= '04baf52c-e083-11ea-9564-000c29298862:2'/*!*/;
SET @@SESSION.GTID_NEXT= '04baf52c-e083-11ea-9564-000c29298862:3'/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
[root@localhost mysql]#
GTID的生命周期介绍：
1.事务提交时会获取到一个GTID，该GTID将位于事务前面一同被记录到二进制日志中。若事务不被记录到二进制日志中，它也不会获取到GTID。
2.事务的GTID会以Gtid_log_event的形式记录到二进制日志，当二进制日志轮换或实例关闭时，MySQL会将所有已写入二进制日志的事务的GTID刷新到系统表mysql.gtid_executed。
{
这里说明一下gtid_executed表的刷新机制：
【1】主库上mysql.gtid_executed也是会进行更新，开启了binlog后，会在binlog rotation时进行更新(比如执行：flush logs;)。
【2】备库上mysql.gtid_executed表的更新情况主要取决于log_slave_updates参数。log_slave_updates = ON，不会每个事务进行实时更新，而是在binary log rotation的时候会更新并进行压缩。log_slave_updates = OFF，备库上的mysql.gtid_executed会每一个事务进行更新。并且，此时mysql.gtid_executed表的压缩取决于executed_gtids_compression_period，默认为1000个事务进行压缩。
【3】MySQL 5.6版本开启GTID模式，必须打开参数log_slave_updates，简单来说就是必须在从机上再记录一份二进制日志。这样的无论对性能还是存储的开销，无疑会相应的增大。而从MySQL 5.7.5版本开始无需在GTID模式下启用参数log_slave_updates，而是将GTID值持久化保存在一张InnoDB表中，并与用户事务一起进行提交，从而实现数据的一致性。
【4】关于log_slave_updates 参数
Normally, a slave does not log to its own binary log any updates that are received from a master server.This option tells the slave to log the updates performed by its SQL thread to its own binary log.For this option to have any effect, the slave must also be started with the –log-bin option to enable binary logging.Prior to MySQL 5.5, the server would not start when using the –log-slave-updates option without also startingthe server with the –log-bin option, and would fail with an error; in MySQL 5.5, only a warning is generated.
(Bug #44663) –log-slave-updates is used when you want to chain replication servers.For example, you might want to set up replication servers using this arrangement: A -> B -> CHere, A serves as the master for the slave B, and B serves as the master for the slave C.For this to work, B must be both a master and a slave. You must start both A and B with –log-bin to enable binary logging,and B with the –log-slave-updates option so that updates received from A are logged by B to its binary log.
}
3.事务提交后，极短时间内其GTID会被加入到一个GTID集合中（注意该过程不具有原子性），即全局系统变量gtid_executed，它代表全部已提交了的事务的GTID。在复制关系中，它也表明了该从实例已执行过哪些事务，主节点会据此判断还需发送哪些GTID。
4.当二进制日志传送到从节点转储为中继日志后，从节点会读取GTID，在会话级别将该GTID赋值给会话系统变量gtid_next，这也就告诉了从节点接下来要执行的事务的GTID是什么。
5.从节点会确认会话系统变量gtid_next中的GTID没被占用，然后为其分配一个线程，并使用全局系统变量gtid_owned（@@GLOBAL.gtid_owned）标识出该GTID和使用它的线程的ID。若该GTID已被使用，就忽略该事务。
6.若此GTID没被使用，从节点会回放该事务。从节点会使用会话系统变量gtid_next中的GTID，作为该事务的GTID，而不会为其重新生成GTID。
7.若从节点开启了二进制日志，该GTID会以Gtid_log_event的形式和事务一同记录进二进制日志。当二进制日志轮换或实例关闭时，所有已提交事务的GTID又会被刷新到系统表mysql.gtid_executed（同2）。
8.若从节点没开启二进制日志，MySQL会将回放该事务和将其GTID直接写入系统表mysql.gtid_executed作为一个事务进行，但在MySQL 5.7版本这还仅限于DML语句，在8.0版本，DDL也可以了。
9.当事务在从节点回放后，从节点上全局系统变量gtid_executed的变化同3。
附：多线程复制
在5.6中被引入，并且在5.7中得到了进一步的完善，5.7中是基于逻辑时钟的方式进行的多线程复制。
参阅：
https://www.cnblogs.com/f-ck-need-u/p/9164823.html