Linux下MySQL主从复制(GTID)+读写分离(ProxySQL)-实施笔记

GTID概念：

• GTID（ Global Transaction Identifier）全局事务标识。GTID 是 5.6 版本引入的一个有关于主从复制的重大改进，相对于之前版本基于 Binlog 文件 + Position 的主从复制，基于 GTID 的主从复制，数据一致性更高，主从数据复制更健壮，主从切换、故障切换不易出错，很少需要人为介入处理。
• GTID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，保存在mysql数据目录下的$datadir/auto.cnf文件里。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：3E11FA47-71CA-11E1-9E33-C80AA9429562:23。如果复制结构中，任意两台服务器uuid重复的话(比如直接冷备份时，auto.conf中的内容是一致的)，在启动复制功能的时候会报错。这时可以删除auto.conf文件再重启mysqld。

GTID的工作原理：

从服务器连接到主服务器之后，把自己执行过的GTID (Executed_Gtid_Set: 即已经执行的事务编码)<SQL线程> 、获取到的GTID (Retrieved_Gtid_Set: 即从库已经接收到主库的事务编号) <IO线程>发给主服务器，主服务器把从服务器缺少的GTID及对应的transactions发过去补全即可。当主服务器挂掉的时候，找出同步最成功的那台从服务器，直接把它提升为主即可。如果硬要指定某一台不是最新的从服务器提升为主， 先change到同步最成功的那台从服务器， 等把GTID全部补全了，就可以把它提升为主了。

　　简单概述如下：

• 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。
• 3.sql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。

GTID的生命周期：gtid的生命周期对于配置和维护基于gtid的复制至关重要。

• 1.GTID在主库提交事务的flush阶段产生，但并非所有事务都会产生GTID(如只读事务)
• 2.事务拿到GTID后，会生成Gtid_log_event，在提交的时候会记录到binlog event事务的开头。
• 3.在binlog写满或者服务器关闭的时候，服务器会把这个binlog所有的GTID写到mysql.gtid_executed表里进行持久化。
• 4.当事务提交后，事务会把分配到的Gtid添加到gtid_executed系统变量中。gtid_executed里面记录的所有提交的GTID事务，它是实时的。
• 5.binlog发送到从库的relay log中，从库读取binlog event里面的Gtid，并设置自己的gtid_next变量为读到的gtid值，从库在进行下一个事务，就会使用这个GTID来提交事务。
• 6.从库先会判断当前是否有线程正持有这个Gtid，也会确定这个Gtid对应的事务是否已经执行过了。已经执行的事务会被跳过。gtid_owned专门用来存储当前正被线程持有的Gtid，事务提交成功，也会把Gtid从gtid_owned集合里释放。
• 7.如果从库开启了binlog，GTID也会伴随Gtid_event_log写到binlog里，这和主库的逻辑一样，在重启和binlog写满的逻辑也一样。
• 8.如果从库没有开启binlog，从库的GTID只能通过gtid_executed表来存储，每次事务提交，GTID会实时写入到gtid_executed表中，这个时候gtid_executed变量和gtid_executed表的数据是同步的。

 GTID的优缺点：

• 优点：
  • 1.保证同一个事务在某slave上绝对只执行一次，没有执行过的gtid事务总是会被执行。
  • 2.不用像传统复制那样保证binlog的坐标准确，因为根本不需要binlog以及坐标。
  • 3.故障转移到新的master的时候很方便，简化了很多任务。
  • 4.很容易判断master和slave的数据是否一致。只要master上提交的事务在slave上也提交了，那么一定是一致的。
  • 5.当然，MySQL提供了选项可以控制跳过某些gtid事务，防止slave第一次启动复制时执行master上的所有事务而导致耗时过久。
  • 6.虽然对于row-based和statement-based的格式都能进行gtid复制，但建议采用row-based格式。
• 缺点：
  • 1.不支持非事务引擎。
  • 2.在一个复制组中，必须要求统一开启GTID或者是关闭GTID
  • 3.不支持sql_slave_skip_counter(一般用这个来跳过基于binlog主从复制出现的问题)。
  • 4.不允许一个SQL同时更新一个事务引擎表和非事务引擎表。
  • 5.为了保证事务的安全性，create table ... select无法使用。不能使用create temporary table创建临时表。不能使用关联更新事务表和非事务表。

MySQL GTID复制部署过程如下。

• MySQL5.7 GTID复制官方文档：https://dev.mysql.com/doc/refman/5.7/en/replication-gtids.html
•  准备环境

属性	主数据库	从数据库
节点	Mysql-Master01	Mysql-Slave01
系统	CentOS Linux release 7.5.1804 (Minimal)	CentOS Linux release 7.5.1804 (Minimal)
内核	3.10.0-862.el7.x86_64	3.10.0-862.el7.x86_64
SELinux	setenforce 0 | disabled	setenforce 0 | disabled
Firewlld	systemctl stop/disable firewalld	systemctl stop/disable firewalld
IP地址	172.16.70.37	172.16.70.181

• Master01，Slave01相同操作部分，以Master01为例。

# 时间同步
[root@Mysql-Master01 ~]# yum install -y ntp
[root@Mysql-Master01 ~]# systemctl start ntpd && systemctl enable ntpd
[root@Mysql-Master01 ~]# timedatectl set-timezone Asia/Shanghai

# yum安装MySQL5.7（默认最新版本）
[root@Mysql-Master01 ~]# wget https://repo.mysql.com/yum/mysql-5.7-community/el/7/x86_64/mysql57-community-release-el7-10.noarch.rpm
[root@Mysql-Master01 ~]# yum localinstall -y mysql57-community-release-el7-10.noarch.rpm
[root@Mysql-Master01 ~]# yum repolist enabled | grep "mysql.*-community.*"
[root@Mysql-Master01 ~]# yum install -y mysql-community-server
[root@Mysql-Master01 ~]# mysql -V
mysql  Ver 14.14 Distrib 5.7.35, for Linux (x86_64) using  EditLine wrapper

# 启动MySQL
[root@Mysql-Master01 ~]# systemctl start mysqld && systemctl enable
Too few arguments.
[root@Mysql-Master01 ~]# systemctl start mysqld && systemctl enable mysqld
[root@Mysql-Master01 ~]# netstat -nutpl | grep mysql
tcp6       0      0 :::3306                 :::*                    LISTEN      2256/mysqld
[root@Mysql-Master01 ~]# ps -ef | grep mysql
mysql      2256      1  0 12:09 ?        00:00:08 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid

# MySQL安全初始化
[root@Mysql-Master01 ~]# grep 'temporary password' /var/log/mysqld.log
2021-08-19T04:08:59.720748Z 1 [Note] A temporary password is generated for root@localhost: .!aTlyih4r2y

[root@Mysql-Master01 ~]# mysql_secure_installation

Securing the MySQL server deployment.

Enter password for user root:　　# 输入MySQL初始密码 .!aTlyih4r2y

The existing password for the user account root has expired. Please set a new password.

New password:　　　　# 输入符合复杂密码策略的新密码

Re-enter new password:　　# 再次输入
The 'validate_password' plugin is installed on the server.
The subsequent steps will run with the existing configuration
of the plugin.
Using existing password for root.

Estimated strength of the password: 100
Change the password for root ? ((Press y|Y for Yes, any other key for No) : n　　　　# 上面以已经修改了，无需再修改

 ... skipping.
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y　　　　# 是否删除匿名用户
Success.

Normally, root should only be allowed to connect from
'localhost'. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y　　# 是否禁用root远程登录
Success.

By default, MySQL comes with a database named 'test' that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.

Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y　　# 是否删除test库和对test库的访问权限
 - Dropping test database...
Success.

 - Removing privileges on test database...
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y　　　# 是否刷新授权表使修改生效
Success.

All done!

• Master01上的操作。

[root@Mysql-Master01 ~]# hostname -I
172.16.70.37

# 设置master01的my.cnf(必须在[mysqld]配置区域)
[root@Mysql-Master01 ~]# cp /etc/my.cnf /etc/my.cnf_bak
[root@Mysql-Master01 ~]# vim /etc/my.cnf
[mysqld]
......
# 新增以下内容
#GTID
server_id = 37　　　　# master01服务器唯一ID，一般IP最后一段，主从不能重复
gtid_mode = on　　　　# 开启gtid模式
enforce_gtid_consistency = on　　# 强制gtid一直性，用于保证启动gitd后事务的安全

#binlog
log_bin = master-bin　　# 开启bin-log，并可指定文件文件目录和前缀
log-slave-updates = 1　 # 在从服务器进入主服务器传入过来的修改日志所使用，在Mysql5.7之前主从架构上使用gtid模式的话，必须使用此选项，在Mysql5.7取消了，会增加系统负载
binlog_format = row　　 # 默认为mixed混合模式，更改为row复制，为了数据一致性，推荐采用row模式
sync-master-info = 1　　# 同步master_info,任何事物提交以后都必须要把事务提交以后的二进制日志事件的位置对应的文件名称，记录到master_info中，下次启动自动读取，保证数据无丢失
sync_binlog = 1　　　　　# 表示binlog进行FSYNC刷盘，同时dump线程会在sync阶段后进行binlog传输 

#relay log
skip_slave_start = 1　　# 跳过slave复制线程

# 重启MySQL
[root@Mysql-Master01 ~]# systemctl restart mysqld

# 登录MySQL
[root@Mysql-Master01 ~]# mysql -p
Enter password:

mysql> show master status;　　# 查看master状态
+-------------------+----------+--------------+------------------+-------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000002 |      154 |              |                  |                   |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> show global variables like '%uuid%';　　
+---------------+--------------------------------------+
| Variable_name | Value                                |
+---------------+--------------------------------------+
| server_uuid   | 2e12d559-00a3-11ec-9494-000c29ceb2c0 |
+---------------+--------------------------------------+
1 row in set (0.01 sec)

mysql> show global variables like '%gtid%';　　　　# 查看gtid功能是否开启
+----------------------------------+-------+
| Variable_name                    | Value |
+----------------------------------+-------+
| binlog_gtid_simple_recovery      | ON    |
| enforce_gtid_consistency         | ON    |
| gtid_executed                    |       |
| gtid_executed_compression_period | 1000  |
| gtid_mode                        | ON    |
| gtid_owned                       |       |
| gtid_purged                      |       |
| session_track_gtids              | OFF   |
+----------------------------------+-------+
8 rows in set (0.00 sec)

mysql> show global variables like 'server_id';　　# 查看服务器唯一ID
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 37    |
+---------------+-------+
1 row in set (0.00 sec)

mysql> show global variables like '%log_bin%';　　　　# 查看binlog日志是否开启
+---------------------------------+---------------------------------+
| Variable_name                   | Value                           |
+---------------------------------+---------------------------------+
| log_bin                         | ON                              |
| log_bin_basename                | /var/lib/mysql/master-bin       |
| log_bin_index                   | /var/lib/mysql/master-bin.index |
| log_bin_trust_function_creators | OFF                             |
| log_bin_use_v1_row_events       | OFF                             |
+---------------------------------+---------------------------------+
5 rows in set (0.01 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO 'backup'@'172.16.%.%' IDENTIFIED BY 'Backup@01';　　　　# 建立backup账户并授权slave
Query OK, 0 rows affected, 1 warning (0.00 sec)

语句说明：
(1) replication slave为mysql同步的必须权限，此处不要授权all权限
(2) *.* 表示所有库所有表，也可以指定具体的库和表进行复制。例如mydb.tb1中，mydb为库名，tb1为表名
(3) 'backup'@'172.16.%.%' backup为同步账号。172.16.%.%为授权主机网段，使用了%表示允许整个172.16.0.0网段可以用backup这个用户访问数据库
(4) identified by 'Backup@01';  Backup@01为密码，实际环境下设置复杂密码

mysql> flush privileges;　　　　# 刷新权限
Query OK, 0 rows affected (0.01 sec)

mysql> select user,host from mysql.user where user='backup';　　　　# 查看是否存在backup用户
+--------+------------+
| user   | host       |
+--------+------------+
| backup | 172.16.%.% |
+--------+------------+
1 row in set (0.01 sec)

mysql> show grants for backup@'172.16.%.%';　　　　# 查看backup用户授权
+---------------------------------------------------------+
| Grants for backup@172.16.%.%                            |
+---------------------------------------------------------+
| GRANT REPLICATION SLAVE ON *.* TO 'backup'@'172.16.%.%' |
+---------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show master status;　　# 再次查看master状态
+-------------------+----------+--------------+------------------+------------------------------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+-------------------+----------+--------------+------------------+------------------------------------------+
| master-bin.000002 |      600 |              |                  | 2e12d559-00a3-11ec-9494-000c29ceb2c0:1-2 |
+-------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

# 创建测试库mydb01
mysql> CREATE DATABASE IF NOT EXISTS mydb01;
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO mydb01.tb01 VALUES(1,"zhangsan"),(2,"lisi");
Query OK, 2 rows affected (0.04 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> SELECT * FROM mydb01.tb01;
+----+----------+
| id | name     |
+----+----------+
|  1 | zhangsan |
|  2 | lisi     |
+----+----------+
2 rows in set (0.00 sec)

mysql> flush table with read lock;　　　　# 对主数据库锁表只读，防止导出数据库的时候有数据写入。unlock tables命令解除锁定
Query OK, 0 rows affected (0.01 sec)

mysql> show variables like '%timeout%';　　　　
+-----------------------------+----------+
| Variable_name               | Value    |
+-----------------------------+----------+
| connect_timeout             | 10       |
| delayed_insert_timeout      | 300      |
| have_statement_timeout      | YES      |
| innodb_flush_log_at_timeout | 1        |
| innodb_lock_wait_timeout    | 50       |
| innodb_rollback_on_timeout  | OFF      |
| interactive_timeout         | 28800    |　　# 自动解锁时间受本参数影响
| lock_wait_timeout           | 31536000 |
| net_read_timeout            | 30       |
| net_write_timeout           | 60       |
| rpl_stop_slave_timeout      | 31536000 |
| slave_net_timeout           | 60       |
| wait_timeout                | 28800    |　　# 自动解锁时间受本参数影响
+-----------------------------+----------+
13 rows in set (0.01 sec)

mysql> show master status;　　# 锁表后查看主库状态
+-------------------+----------+--------------+------------------+------------------------------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+-------------------+----------+--------------+------------------+------------------------------------------+
| master-bin.000002 |     1300 |              |                  | 2e12d559-00a3-11ec-9494-000c29ceb2c0:1-5 |
+-------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

# 备份mydb01数据库,发送至slave01
[root@Mysql-Master01 ~]# mysqldump --single-transaction --master-data=2 --triggers --routines --databases mydb01 -uroot -p > /root/mydb01.sql
Enter password:

注意：
　　mysql5.6使用mysqldump备份时，指定备份的具体库，使用--database
　　mysql5.7使用mysqldump备份时，指定备份的具体库，使用--databases

[root@Mysql-Master01 ~]# rsync -avz /root/mydb01.sql root@172.16.70.181:/root/
The authenticity of host '172.16.70.181 (172.16.70.181)' can't be established.
ECDSA key fingerprint is SHA256:c/5+RMbf79VeNEzwtdtk9cvRoWIDDRg890ew82Hfj+g.
ECDSA key fingerprint is MD5:41:ce:da:7c:7d:ce:93:ed:6f:c3:1d:81:6d:02:18:3b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.70.181' (ECDSA) to the list of known hosts.
root@172.16.70.181's password:　　# slave01服务器root密码

#导出数据完毕后，解锁主库
[root@Mysql-Master01 ~]# mysql -p
Enter password:

mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)

• Slave01上的操作。

[root@Mysql-Slave01 ~]# cp /etc/my.cnf /etc/my.cnf_bak
[root@Mysql-Slave01 ~]# vim /etc/my.cnf
[mysqld]
#GTID
server_id = 181　　　　# 差异项
gtid_mode = on
enforce_gtid_consistency = on

#binlog
log_bin = slave-bin　　# 差异项
log-slave-updates = 1
binlog_format = row
sync-master-info = 1
sync_binlog = 1

#relay log
skip_slave_start = 1
read_only = on　　# 差异项;使从服务器只能进行读取操作，此参数对超级用户无效，并且不会影响从服务器的复制

# 重启MySQL
[root@Mysql-Slave01 ~]# systemctl restart mysqld

# 登录MySQL
[root@Mysql-Slave01 ~]# mysql -p
Enter password:

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.01 sec)

mysql> source /root/mydb01.sql;

mysql> select * from mydb01.tb01;
+----+----------+
| id | name     |
+----+----------+
|  1 | zhangsan |
|  2 | lisi     |
+----+----------+
2 rows in set (0.00 sec)

mysql> show variables like 'server_id';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id     | 181   |
+---------------+-------+
1 row in set (0.01 sec)

mysql> show variables like '%log_bin%';
+---------------------------------+---------------------------------+
| Variable_name                   | Value                           |
+---------------------------------+---------------------------------+
| log_bin                         | ON                              |
| log_bin_basename                | /var/lib/mysql/master-bin       |
| log_bin_index                   | /var/lib/mysql/master-bin.index |
| log_bin_trust_function_creators | OFF                             |
| log_bin_use_v1_row_events       | OFF                             |
| sql_log_bin                     | ON                              |
+---------------------------------+---------------------------------+
6 rows in set (0.00 sec)

# 配置主从同步指令 change master
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> change master to master_host='172.16.70.37',master_port=3306,master_user='backup',master_password='Backup@01',master_auto_position=1;
Query OK, 0 rows affected, 2 warnings (0.03 sec)

参数说明：（提示：字符串用单引号括起来，数值不用引号，注意内容前后不能有空格。）
　　change master to
　　master_host='172.16.70.37'　　# master主库IP
　　master_port=3306　　　　　　　　# 数据库端口号　　　　　　　　
　　master_user='backup'　　　　　　# master上创建用于复制的用户
　　master_password='Backup@01'　　# 复制用户的密码
　　master_auto_position=1　　　　　# gtid复制必须设置此项
-------------------------------------------------------------------------
# 上述操作的原理实际上是把用户密码等信息写入从库新的master.info文件中
[root@Mysql-Slave01 ~]# cat /var/lib/mysql/*.info
25

4
172.16.70.37
backup
Backup@01
3306
60
...
--------------------------------------------------------------------------

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.16.70.37
                  Master_User: backup
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-bin.000002
          Read_Master_Log_Pos: 1300
               Relay_Log_File: Mysql-Slave01-relay-bin.000002
                Relay_Log_Pos: 417
        Relay_Master_Log_File: master-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: 1300
              Relay_Log_Space: 632
              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: 37
                  Master_UUID: 2e12d559-00a3-11ec-9494-000c29ceb2c0
             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: 2e12d559-00a3-11ec-9494-000c29ceb2c0:1-5　　　　# master主数据库的GTID
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

ERROR:
No query specifie

如上，当IO和SQL线程的状态均为Yes，则表示主从已实现同步了！(主从同步是否成功，最关键的为下面的3项状态参数)
Slave_IO_Running: Yes,这个时I/O线程状态，I/O线程负责从从库到主库读取binlog日志，并写入从库的中继日志，状态为Yes表示I/O线程工作正常。
Slave_SQL_Running: Yes,这个是SQL线程状态，SQL线程负责读取中继日志（relay-log）中的数据并转换为SQL语句应用到从数据库中，状态为Yes表示I/O线程工作正常。
Seconds_Behind_Master:0,这个是复制过程中从库比主库延迟的秒数，这个参数极度重要，但企业里更准确地判断主从延迟的方法为：在主库写时间戳，然后从库读取时间戳，和当前数据库时间进行比较，从而认定是否延迟。

===============================================================================
# 再次回到master01机，查看master状态
mysql> show slave hosts;
+-----------+------+------+-----------+--------------------------------------+
| Server_id | Host | Port | Master_id | Slave_UUID                           |
+-----------+------+------+-----------+--------------------------------------+
|       181 |      | 3306 |        37 | 343429c9-00a3-11ec-a6e0-000c29191ffb |
+-----------+------+------+-----------+--------------------------------------+
1 row in set (0.00 sec

• 测试验证MySQL主从复制效果。

# 在172.16.70.37(master01)的主数据库插入新数据
mysql> insert into mydb01.tb01 values(11,"chenqi"),(12,"huangba");
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from mydb01.tb01;
+----+----------+
| id | name     |
+----+----------+
|  1 | zhangsan |
|  2 | lisi     |
| 11 | chenqi   |
| 12 | huangba  |
+----+----------+
4 rows in set (0.00 sec)

# 然后到172.16.70.181(slave01)上查看是否自动同步
mysql> select * from mydb01.tb01;
+----+----------+
| id | name     |
+----+----------+
|  1 | zhangsan |
|  2 | lisi     |
| 11 | chenqi   |
| 12 | huangba  |
+----+----------+
4 rows in set (0.00 sec)

至此，MySQL主从复制(GTID)已经实现！

MySqL的读写分离器MySql-Proxy

• MySql Proxy是一个处于MySql Client端和MySql Server端之间的简单程序，它可以监测、分析或改变它们的通信。它使用灵活，没有限制，常见的用途包括：负载平衡、故障分析、查询过渡和修改等。MySqL Proxy就是这么一个中间层代理，简单地说，MySql Proxy就是一个连接池，负责将前台应用的连接请求转发给后台的数据库，并且通过使用Lua脚本，实现复杂的连接控制和过渡，从而实现读写分离和负载平衡。
• 对于应用来说，Mysql Proxy是完全透明的，应用则只是需要连接到MySql Proxy的监听端口即可。当然，这样Proxy机器可能成为单点失效，但完全可以使用多个Proxy机器作为冗余，在应用服务器的连接池配置中配置多个Proxy的连接参数即可。
• MySql Proxy更强大的一项功能是实现“读写分离”，基本原理是让主数据库处理事务性查询，让从数据库处理SELECT查询，数据复制（Replication）用来把主库的变更同步到集群中的从库上。在生成MySql的M-S结构后，实现读写分离，需要使用MySql Proxy。
• 官方ProxySQL文档：https://proxysql.com/documentation/

Mysql-Proxy读写分离部署。

属性	主数据库	从数据库	中间件
节点	Mysql-Master01	Mysql-Slave01	Mysql-Proxy01
系统	CentOS Linux release 7.5.1804 (Minimal)	CentOS Linux release 7.5.1804 (Minimal)	CentOS Linux release 7.5.1804 (Minimal)
内核	3.10.0-862.el7.x86_64	3.10.0-862.el7.x86_64	3.10.0-862.el7.x86_64
SELinux	setenforce 0 | disabled	setenforce 0 | disabled	setenforce 0 | disabled
Firewlld	systemctl stop/disable firewalld	systemctl stop/disable firewalld	systemctl stop/disable firewalld
IP地址	172.16.70.37	172.16.70.181	172.16.70.182

• 在Mysql-Master01上执行。

# 配置监控后端MySQL节点。(在master主数据节点上创建一个用于监控的用户名(只需在master上创建即可，因为会复制到slave上)，这个用户名只需具有USAGE权限即可)
[root@Mysql-Master01 ~]# mysql -p
Enter password:

mysql> create user monitor@'172.16.70.%' identified by 'Monitor@01';
Query OK, 0 rows affected (0.01 sec)

mysql> grant replication client on *.* to monitor@'172.16.70.%';
Query OK, 0 rows affected (0.01 sec)

mysql> grant all on *.* to root@'172.16.70.%' identified by 'Password@01';
Query OK, 0 rows affected, 1 warning (0.00 sec)

# 配置mysql_users
mysql> grant all on *.* to stnduser@'172.16.70.%' identified by 'Password@01';
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> show grants for monitor@'172.16.70.%';
+------------------------------------------------------------+
| Grants for monitor@172.16.70.%                             |
+------------------------------------------------------------+
| GRANT REPLICATION CLIENT ON *.* TO 'monitor'@'172.16.70.%' |
+------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)

• 在Mysql-Proxy01上执行。

# CentOS 添加仓库（根据需要选择适合版本，这里选择proxysql-2.1.x 版本）
[root@Mysql-Proxy01 ~]# vim /etc/yum.repos.d/proxysql.repo
[proxysql_repo]
name= ProxySQL YUM repository
baseurl=http://repo.proxysql.com/ProxySQL/proxysql-2.1.x/centos/$releasever
gpgcheck=1
gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key

# 执行安装
[root@Mysql-Proxy01 ~]# yum install proxysql -y
[root@Mysql-Proxy01 ~]# proxysql -V
ProxySQL version 2.1.1-40-g1c2b7e4, codename Truls

# 启动proxsql
[root@Mysql-Proxy01 ~]# systemctl start proxysql && systemctl enable proxysql

# 监听两默认端口：6032，6033
[root@Mysql-Proxy01 ~]# systemctl start proxysql && systemctl enable proxysql
[root@Mysql-Proxy01 ~]# netstat -nutpl | grep proxy
tcp        0      0 0.0.0.0:6032            0.0.0.0:*               LISTEN      2885/proxysql
tcp        0      0 0.0.0.0:6033            0.0.0.0:*               LISTEN      2885/proxysql
[root@Mysql-Proxy01 ~]# ps -ef | grep proxy
proxysql   2884      1  0 Aug23 ?        00:00:00 /usr/bin/proxysql --idle-threads -c /etc/proxysql.cnf
proxysql   2885   2884  0 Aug23 ?        00:06:08 /usr/bin/proxysql --idle-threads -c /etc/proxysql.cnf

# 默认配置文件/etc/proxysql.cnf
[root@Mysql-Proxy01 ~]# grep -Ev '#|^$' /etc/proxysql.cnf
datadir="/var/lib/proxysql"
admin_variables=
{
    admin_credentials="admin:admin"　　　　　　# 管理接口默认账号：密码(可修改)
    mysql_ifaces="0.0.0.0:6032"　　　　　　　　# 客户端接口端口
}
mysql_variables=
{
    threads=4
    max_connections=2048
    default_query_delay=0
    default_query_timeout=36000000
    have_compress=true
    poll_timeout=2000
    interfaces="0.0.0.0:6033"
    default_schema="information_schema"
    stacksize=1048576
    server_version="5.5.30"
    connect_timeout_server=3000
    monitor_username="monitor"
    monitor_password="monitor"
    monitor_history=600000
    monitor_connect_interval=60000
    monitor_ping_interval=10000
    monitor_read_only_interval=1500
    monitor_read_only_timeout=500
    ping_interval_server_msec=120000
    ping_timeout_server=500
    commands_stats=true
    sessions_sort=true
    connect_retries_on_failure=10
}
mysql_servers =
(
)
mysql_users:
(
)
mysql_query_rules:
(
)
scheduler=
(
)
mysql_replication_hostgroups=
(
)

# 登录管理界面（使用默认凭据）
[root@Mysql-Proxy01 ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1
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 2
Server version: 5.5.30 (ProxySQL Admin Module)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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> show databases;
+-----+---------------+-------------------------------------+
| seq | name          | file                                |
+-----+---------------+-------------------------------------+
| 0   | main          |                                     |
| 2   | disk          | /var/lib/proxysql/proxysql.db       |
| 3   | stats         |                                     |
| 4   | monitor       |                                     |
| 5   | stats_history | /var/lib/proxysql/proxysql_stats.db |
+-----+---------------+-------------------------------------+
5 rows in set (0.00 sec)

mysql> show tables from main;
+----------------------------------------------------+
| tables                                             |
+----------------------------------------------------+
| global_variables                                   |
| mysql_aws_aurora_hostgroups                        |
| mysql_collations                                   |
| mysql_firewall_whitelist_rules                     |
| mysql_firewall_whitelist_sqli_fingerprints         |
| mysql_firewall_whitelist_users                     |
| mysql_galera_hostgroups                            |
| mysql_group_replication_hostgroups                 |
| mysql_query_rules                                  |
| mysql_query_rules_fast_routing                     |
| mysql_replication_hostgroups                       |
| mysql_servers                                      |
| mysql_users                                        |
| proxysql_servers                                   |
| restapi_routes                                     |
| runtime_checksums_values                           |
| runtime_global_variables                           |
| runtime_mysql_aws_aurora_hostgroups                |
| runtime_mysql_firewall_whitelist_rules             |
| runtime_mysql_firewall_whitelist_sqli_fingerprints |
| runtime_mysql_firewall_whitelist_users             |
| runtime_mysql_galera_hostgroups                    |
| runtime_mysql_group_replication_hostgroups         |
| runtime_mysql_query_rules                          |
| runtime_mysql_query_rules_fast_routing             |
| runtime_mysql_replication_hostgroups               |
| runtime_mysql_servers                              |
| runtime_mysql_users                                |
| runtime_proxysql_servers                           |
| runtime_restapi_routes                             |
| runtime_scheduler                                  |
| scheduler                                          |
+----------------------------------------------------+
32 rows in set (0.00 sec)

说明重要字段含义：
global_variables       设置变量，包括监听的端口、管理账号等。
mysql_collations       相关字符集和校验规则。
mysql_query_rules   　　定义查询路由规则。

mysql> show tables from monitor;
+--------------------------------------+
| tables                               |
+--------------------------------------+
| mysql_server_aws_aurora_check_status |
| mysql_server_aws_aurora_failovers    |
| mysql_server_aws_aurora_log          |
| mysql_server_connect_log             |
| mysql_server_galera_log              |
| mysql_server_group_replication_log   |
| mysql_server_ping_log                |
| mysql_server_read_only_log           |
| mysql_server_replication_lag_log     |
+--------------------------------------+
9 rows in set (0.00 sec)

注意：runtime_开头的是运行时的配置，这些是不能修改的。要修改ProxySQL的配置，需要修改了非runtime_表，修改后必须执行LOAD ... TO RUNTIME
　　　才能加载到RUNTIME生效，执行save ... to disk才能将配置持久化保存到磁盘。

# 添加MySQL节点，使用insert语句添加主机到mysql_servers表中，其中：hostgroup_id 1 表示写组，2表示读组
mysql> insert into mysql_servers(hostgroup_id,hostname,port) values(1,'172.16.70.37',3306);
Query OK, 1 row affected (0.00 sec)

mysql> insert into mysql_servers(hostgroup_id,hostname,port) values(1,'172.16.70.181',3306);
Query OK, 1 row affected (0.00 sec)

mysql> select * from mysql_servers;　　　# 查看insert结果
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname      | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1            | 172.16.70.37  | 3306 | 0         | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
| 1            | 172.16.70.181 | 3306 | 0         | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.00 sec)

# 监控用户的凭据添加到 ProxySQL
mysql> update global_variables set variable_value='monitor' where variable_name='mysql-monitor_username';
Query OK, 0 rows affected (0.00 sec)

mysql> update global_variables set variable_value='Monitor@01' where variable_name='mysql-monitor_password';
Query OK, 0 rows affected (0.01 sec)

mysql> select * from global_variables where variable_name like 'mysql-monitor_%';
+--------------------------------------------------------------+----------------+
| variable_name                                                | variable_value |
+--------------------------------------------------------------+----------------+
| mysql-monitor_enabled                                        | true           |
| mysql-monitor_connect_timeout                                | 600            |
| mysql-monitor_ping_max_failures                              | 3              |
| mysql-monitor_ping_timeout                                   | 1000           |
| mysql-monitor_read_only_max_timeout_count                    | 3              |
| mysql-monitor_replication_lag_interval                       | 10000          |
| mysql-monitor_replication_lag_timeout                        | 1000           |
| mysql-monitor_replication_lag_count                          | 1              |
| mysql-monitor_groupreplication_healthcheck_interval          | 5000           |
| mysql-monitor_groupreplication_healthcheck_timeout           | 800            |
| mysql-monitor_groupreplication_healthcheck_max_timeout_count | 3              |
| mysql-monitor_groupreplication_max_transactions_behind_count | 3              |
| mysql-monitor_galera_healthcheck_interval                    | 5000           |
| mysql-monitor_galera_healthcheck_timeout                     | 800            |
| mysql-monitor_galera_healthcheck_max_timeout_count           | 3              |
| mysql-monitor_replication_lag_use_percona_heartbeat          |                |
| mysql-monitor_query_interval                                 | 60000          |
| mysql-monitor_query_timeout                                  | 100            |
| mysql-monitor_slave_lag_when_null                            | 60             |
| mysql-monitor_threads_min                                    | 8              |
| mysql-monitor_threads_max                                    | 128            |
| mysql-monitor_threads_queue_maxsize                          | 128            |
| mysql-monitor_wait_timeout                                   | true           |
| mysql-monitor_writer_is_also_reader                          | true           |
| mysql-monitor_username                                       | monitor        |　　# 自定义项
| mysql-monitor_password                                       | Monitor@01     |　　# 自定义项
| mysql-monitor_history                                        | 600000         |
| mysql-monitor_connect_interval                               | 60000          |
| mysql-monitor_ping_interval                                  | 10000          |
| mysql-monitor_read_only_interval                             | 1500           |
| mysql-monitor_read_only_timeout                              | 500            |
+--------------------------------------------------------------+----------------+
31 rows in set (0.00 sec)

# 激活配置，并保存到磁盘
mysql> load mysql servers to runtime;
Query OK, 0 rows affected (0.00 sec)

mysql> save mysql servers to disk;
Query OK, 0 rows affected (0.06 sec)

# 指定一对 READER 和 WRITER 主机组进行配置（写组id:1 ; 读组id:2）
mysql> insert into mysql_replication_hostgroups (writer_hostgroup,reader_hostgroup,comment) values (1,2,'cluster1');
Query OK, 1 row affected (0.00 sec)

mysql> select * from mysql_replication_hostgroups;
+------------------+------------------+------------+----------+
| writer_hostgroup | reader_hostgroup | check_type | comment  |
+------------------+------------------+------------+----------+
| 1                | 2                | read_only  | cluster1 |
+------------------+------------------+------------+----------+
1 row in set (0.00 sec)

mysql> load mysql servers to runtime;
Query OK, 0 rows affected (0.00 sec)

# 后台健康检查
mysql> show tables from monitor;
+------------------------------------+
| tables                             |
+------------------------------------+
| mysql_server_connect_log           |
| mysql_server_group_replication_log |
| mysql_server_ping_log              |
| mysql_server_read_only_log         |
| mysql_server_replication_lag_log   |
+------------------------------------+
5 rows in set (0.00 sec)

mysql> select * from monitor.mysql_server_connect_log order by time_start_us desc limit 2;　　# 对心跳信息的监控（connect_log）
+---------------+------+------------------+-------------------------+---------------+
| hostname      | port | time_start_us    | connect_success_time_us | connect_error |
+---------------+------+------------------+-------------------------+---------------+
| 172.16.70.37  | 3306 | 1629795694640282 | 3725                    | NULL          |
| 172.16.70.181 | 3306 | 1629795693592247 | 4307                    | NULL          |
+---------------+------+------------------+-------------------------+---------------+
2 rows in set (0.00 sec)

mysql> select * from monitor.mysql_server_ping_log order by time_start_us desc limit 2;　　　　# 对心跳信息的监控（ping_log）
+---------------+------+------------------+----------------------+------------+
| hostname      | port | time_start_us    | ping_success_time_us | ping_error |
+---------------+------+------------------+----------------------+------------+
| 172.16.70.181 | 3306 | 1629795783687130 | 1114                 | NULL       |
| 172.16.70.37  | 3306 | 1629795783546617 | 716                  | NULL       |
+---------------+------+------------------+----------------------+------------+
2 rows in set (0.00 sec

mysql> select * from mysql_servers;
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname      | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 1            | 172.16.70.37  | 3306 | 0         | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
| 2            | 172.16.70.181 | 3306 | 0         | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
+--------------+---------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
2 rows in set (0.00 sec)

# 配置mysql_users
mysql> insert into mysql_users(username,password,default_hostgroup) values('root','Password@01',1);
Query OK, 1 row affected (0.01 sec)

mysql> insert into mysql_users(username,password,default_hostgroup) values('stnduser','Password@01',1);
Query OK, 1 row affected (0.00 sec)

mysql_users表有不少字段，最主要的三个字段为username、password和default_hostgroup：
    username：前端连接ProxySQL，以及ProxySQL将SQL语句路由给MySQL所使用的用户名。
    password：用户名对应的密码。可以是明文密码，也可以是hash密码。如果想使用hash密码，可以先在某个MySQL节点上执行select password(PASSWORD)，然后将加密结果复制到该字段。
    default_hostgroup：该用户名默认的路由目标。例如，指定root用户的该字段值为10时，则使用root用户发送的SQL语句默认情况下将路由到hostgroup_id=10组中的某个节点。

mysql> select * from mysql_users\G
*************************** 1. row ***************************
              username: root
              password: Password@01
                active: 1
               use_ssl: 0
     default_hostgroup: 1
        default_schema: NULL
         schema_locked: 0
transaction_persistent: 1
          fast_forward: 0
               backend: 1
              frontend: 1
       max_connections: 10000
            attributes:
               comment:
*************************** 2. row ***************************
              username: stnduser
              password: Password@01
                active: 1
               use_ssl: 0
     default_hostgroup: 1
        default_schema: NULL
         schema_locked: 0
transaction_persistent: 1
          fast_forward: 0
               backend: 1
              frontend: 1
       max_connections: 10000
            attributes:
               comment:
2 rows in set (0.00 sec)

mysql> update mysql_users set transaction_persistent=1 where username='root';
Query OK, 1 row affected (0.00 sec)

mysql> update mysql_users set transaction_persistent=1 where username='stnduser';
Query OK, 1 row affected (0.00 sec)

mysql> load mysql users to runtime;
Query OK, 0 rows affected (0.01 sec)

mysql> save mysql users to disk;
Query OK, 0 rows affected (0.02 sec)

# 测试连接终端，分别使用root用户和stnduser用户测试下它们是否能路由到默认的hostgroup_id=1(它是一个写组)读、写数据。
[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1 -e "select @@server_id"；　　# 这是通过转发端口6033连接的，连接的是转发到后端真正的数据库!
+-------------+
| @@server_id |
+-------------+
|          37 |
+-------------+

[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1 -e "create database proxy_db";　　# 远程Mysql-Master01并创建proxy_db
[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1 -e "show databases like 'proxy_db'";
+---------------------+
| Database (proxy_db) |
+---------------------+
| proxy_db            |
+---------------------+

[root@Mysql-Proxy01 ~]# mysql -ustnduser -pPassword@01 -P6033 -h127.0.0.1 -e "show databases like 'proxy_db'";
+---------------------+
| Database (proxy_db) |
+---------------------+
| proxy_db            |
+---------------------+

# Proxy查询规则
mysql> show tables from stats;　　
+--------------------------------------+
| tables                               |
+--------------------------------------+
| global_variables                     |
| stats_memory_metrics                 |
| stats_mysql_commands_counters        |
| stats_mysql_connection_pool          |
| stats_mysql_connection_pool_reset    |
| stats_mysql_errors                   |
| stats_mysql_errors_reset             |
| stats_mysql_free_connections         |
| stats_mysql_global                   |
| stats_mysql_gtid_executed            |
| stats_mysql_prepared_statements_info |
| stats_mysql_processlist              |
| stats_mysql_query_digest             |
| stats_mysql_query_digest_reset       |
| stats_mysql_query_rules              |
| stats_mysql_users                    |
| stats_proxysql_servers_checksums     |
| stats_proxysql_servers_metrics       |
| stats_proxysql_servers_status        |
+--------------------------------------+
19 rows in set (0.00 sec)

mysql> select * from stats.stats_mysql_connection_pool\G　　　　# 显示与 MySQL 后端以及连接和总体流量相关的信息
*************************** 1. row ***************************
        hostgroup: 1
         srv_host: 172.16.70.37
         srv_port: 3306
           status: ONLINE
         ConnUsed: 0
         ConnFree: 1
           ConnOK: 1
          ConnERR: 0
      MaxConnUsed: 1
          Queries: 11
Queries_GTID_sync: 0
  Bytes_data_sent: 258
  Bytes_data_recv: 156
       Latency_us: 1496
*************************** 2. row ***************************
        hostgroup: 2
         srv_host: 172.16.70.181
         srv_port: 3306
           status: ONLINE
         ConnUsed: 0
         ConnFree: 0
           ConnOK: 0
          ConnERR: 0
      MaxConnUsed: 0
          Queries: 0
Queries_GTID_sync: 0
  Bytes_data_sent: 0
  Bytes_data_recv: 0
       Latency_us: 1320
2 rows in set (0.01 sec)

mysql> select * from stats_mysql_commands_counters where total_cnt\G　　　　# 返回有关执行的语句类型和执行时间分布的详细信息
*************************** 1. row ***************************
      Command: CREATE_DATABASE
Total_Time_us: 6514
    Total_cnt: 6
    cnt_100us: 0
    cnt_500us: 1
      cnt_1ms: 2
      cnt_5ms: 3
     cnt_10ms: 0
     cnt_50ms: 0
    cnt_100ms: 0
    cnt_500ms: 0
       cnt_1s: 0
       cnt_5s: 0
      cnt_10s: 0
     cnt_INFs: 0
*************************** 2. row ***************************
      Command: SELECT
Total_Time_us: 2683
    Total_cnt: 13
    cnt_100us: 11
    cnt_500us: 0
      cnt_1ms: 1
      cnt_5ms: 1
     cnt_10ms: 0
     cnt_50ms: 0
    cnt_100ms: 0
    cnt_500ms: 0
       cnt_1s: 0
       cnt_5s: 0
      cnt_10s: 0
     cnt_INFs: 0
*************************** 3. row ***************************
      Command: SHOW
Total_Time_us: 3158
    Total_cnt: 3
    cnt_100us: 0
    cnt_500us: 0
      cnt_1ms: 2
      cnt_5ms: 1
     cnt_10ms: 0
     cnt_50ms: 0
    cnt_100ms: 0
    cnt_500ms: 0
       cnt_1s: 0
       cnt_5s: 0
      cnt_10s: 0
     cnt_INFs: 0
3 rows in set (0.00 sec)

# 插入两个规则，目的是将select语句分离到hostgroup_id=2的读组，但由于select语句中有一个特殊语句SELECT...FOR UPDATE它会申请写锁，所以应该路由到hostgroup_id=1的写组。
mysql> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) VALUES (1,1,'^SELECT.*FOR UPDATE$',1,1), (2,1,'^SELECT',2,1);
Query OK, 2 rows affected (0.01 sec)

说明：
  rule_id        规则的id。规则是按照rule_id的顺序进行处理的。
  active        只有该字段值为1的规则才会加载到runtime数据结构，所以只有这些规则才会被查询处理模块处理。
  username
  match_digest        用户名筛选，当设置为非NULL值时，只有匹配的用户建立的连接发出的查询才会被匹配。
  destination_hostgroup        将匹配到的查询路由到该主机组。但注意，如果用户的transaction_persistent=1(见mysql_users表)，
  　　　　　　　　　　　　　　　　　且该用户建立的连接开启了一个事务，则这个事务内的所有语句都将路由到同一主机组，无视匹配规则。
  apply        当设置为1后，当匹配到该规则后，将立即应用该规则，不会再评估其它的规则(注意：应用之后，将不会评估mysql_query_rules_fast_routing中的规则)。

mysql> load mysql query rules to runtime;
Query OK, 0 rows affected (0.00 sec)

mysql> save mysql query rules to disk;
Query OK, 0 rows affected (0.01 sec)

注意：
　　select ... for update规则的rule_id必须要小于普通的select规则的rule_id，因为ProxySQL是根据rule_id的顺序进行规则匹配的。

# 再次测试，读操作是否给hostgroup_id=2的读组
[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1 -e "select @@server_id"
+-------------+
| @@server_id |
+-------------+
|         181 |
+-------------+

# 再看写操作
[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1 -e 'start transaction;select @@server_id;commit;select @@server_id;'
+-------------+
| @@server_id |
+-------------+
|          37 |
+-------------+
+-------------+
| @@server_id |
+-------------+
|         181 |
+-------------+

# 测试读写分离
[root@Mysql-Proxy01 ~]# mysql -uroot -pPassword@01 -P6033 -h127.0.0.1
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 26
Server version: 5.5.30 (ProxySQL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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> show databses;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb01             |
| mysql              |
| performance_schema |
| proxy_db           |
| sys                |
+--------------------+

# 创建数据
mysql> create table proxy_tb(name varchar(20),age int(4));
Query OK, 0 rows affected (0.03 sec)

mysql> insert into proxy_tb values('zhaojiu','20');
Query OK, 1 row affected (0.01 sec)

# 在proxysql管理端查看读写分离
[root@Mysql-Proxy01 ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1
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 27
Server version: 5.5.30 (ProxySQL Admin Module)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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> select * from stats_mysql_query_digest;
+-----------+--------------------+----------+----------------+--------------------+---------------------------------------------------+------------+------------+------------+----------+----------+----------+-------------------+---------------+
| hostgroup | schemaname         | username | client_address | digest             | digest_text                                       | count_star | first_seen | last_seen  | sum_time | min_time | max_time | sum_rows_affected | sum_rows_sent |
+-----------+--------------------+----------+----------------+--------------------+---------------------------------------------------+------------+------------+------------+----------+----------+----------+-------------------+---------------+
| 2         | proxy_db           | root     |                | 0x4A754D38BB86DC46 | select * from proxy_tb                            | 1          | 1629875080 | 1629875080 | 689      | 689      | 689      | 0                 | 4             |
| 2         | proxy_db           | root     |                | 0x57D3532A839C8743 | SELECT * FROM `proxy_tb` WHERE ?=?                | 1          | 1629875054 | 1629875054 | 9386     | 9386     | 9386     | 0                 | 0             |
| 1         | information_schema | root     |                | 0xF439051B8ABC188E | insert into proxy_tb values(?,?)                  | 1          | 1629875034 | 1629875034 | 5281     | 5281     | 5281     | 0                 | 0             |
| 2         | information_schema | root     |                | 0x620B328FE9D6D71A | SELECT DATABASE()                                 | 2          | 1629865271 | 1629875054 | 6089     | 2261     | 3828     | 0                 | 2             |
| 1         | proxy_db           | root     |                | 0x59D85BA7DD54E405 | create table proxy_tb(name varchar(?),age int(?)) | 1          | 1629865334 | 1629865334 | 29689    | 29689    | 29689    | 0                 | 0             |
+-----------+--------------------+----------+----------------+--------------------+---------------------------------------------------+------------+------------+------------+----------+----------+----------+-------------------+---------------+
5 rows in set (0.00 sec)

# 从上述结果就可以看出读写分离配置是成功的，读请求是转发到2组，写请求转发到1组

说明：
  hostgroup：查询将要路由到的目标主机组。如果值为-1，则表示命中了查询缓存，直接从缓存取数据返回给客户端。
  schemaname：当前正在执行的查询所在的schema名称。
  username：MySQL客户端连接到ProxySQL使用的用户名。
  digest：一个十六进制的hash值，唯一地代表除了参数值部分的查询语句。
  digest_text：参数化后的SQL语句的文本。注意，如果重写了SQL语句，则这个字段是显示的是重写后的字段。换句话说，这个字段是真正路由到后端，被后端节点执行的语句。
  count_star：该查询(参数相同、值不同)总共被执行的次数。
  first_seen：unix格式的timestamp时间戳，表示该查询首次被ProxySQL路由出去的时间点。
  last_seen：unix格式的timestamp时间戳，到目前为止，上一次该查询被ProxySQL路由出去的时间点。
  sum_time：执行该类查询所花的总时间(单位微秒)。在想要找出程序中哪部分语句消耗时间最长的语句时非常有用，此外根据这个结果还能提供一个如何提升性能的良好开端。
  min_time, max_time：执行该类查询的时间范围。min_time表示的是目前为止执行该类查询所花的最短时间，max_time则是目前为止，执行该类查询所花的最长时间，单位都是微秒。

至此，MySQL主从复制(GTID)+读写分离的环境部署已经实现！