MySQL读写分离(ProxySQL)

不念不忘少年蓝@ 2022-01-11 09:31 315阅读 0赞

# MySQL读写分离(ProxySQL) #

## 读写分离原理 ##

读写分离就是用户在发送请求时，请求经过中间件，中间件将请求中的读和写操作分辨出来将读请求发送给后端的从服务器，将写请求发送给后端的主服务器，再又主服务器通过主从复制将数据复制给其他从服务器  
![MySQL读写分离(ProxySQL)][MySQL_ProxySQL]

## 常见MySQL中间件 ##

<table> 
 <thead> 
  <tr> 
   <th style="text-align:left;">名称</th> 
   <th style="text-align:left;">公司</th> 
   <th style="text-align:left;">站点地址</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="text-align:left;">mysql-proxy</td> 
   <td style="text-align:left;">Oracle</td> 
   <td style="text-align:left;"><a href="https://downloads.mysql.com/archives/proxy" rel="nofollow">https://downloads.mysql.com/archives/proxy</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Atlas</td> 
   <td style="text-align:left;">Qihoo</td> 
   <td style="text-align:left;"><a href="https://github.com/Qihoo360/Atlas/blob/master/README_ZH.md" rel="nofollow">https://github.com/Qihoo360/Atlas/blob/master/README_ZH.md</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">dbproxy</td> 
   <td style="text-align:left;">美团</td> 
   <td style="text-align:left;"><a href="https://github.com/Meituan-Dianping/DBProxy" rel="nofollow">https://github.com/Meituan-Dianping/DBProxy</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Cetus</td> 
   <td style="text-align:left;">网易乐得</td> 
   <td style="text-align:left;"><a href="https://github.com/Lede-Inc/cetus" rel="nofollow">https://github.com/Lede-Inc/cetus</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Amoeba</td> 
   <td style="text-align:left;"><a href="https://sourceforge.net/projects/amoeba/" rel="nofollow">https://sourceforge.net/projects/amoeba/</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Cobar</td> 
   <td style="text-align:left;">阿里巴巴</td> 
   <td style="text-align:left;">Amoeba的升级版</td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Mycat</td> 
   <td style="text-align:left;">基于Cobar</td> 
   <td style="text-align:left;"><a href="http://www.mycat.io" rel="nofollow">http://www.mycat.io</a></td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">ProxySQL</td> 
   <td style="text-align:left;"><a href="https://proxysql.com/" rel="nofollow">https://proxysql.com/</a></td> 
  </tr> 
 </tbody> 
</table>

本文以ProxySQL为例来介绍读写分离的使用方法

## ProxySQL简介 ##

ProxySQL为MySQL的中间件，其有两个版本官方版和percona版，percona版是基于官方版基础上修改而来。ProxySQL是由C++语言开发，轻量级但性能优异（支持处理千亿级数据），其具有中间件所需要的绝大多数功能，如：

1.  多种方式的读写分离
2.  定制基于用户、基于schema、基于语言的规则对SQL语句进行路由
3.  缓存查询结果
4.  后端节点的控制  
    ...  
    官方站点：[https://proxysql.com/][https_proxysql.com]  
    官方手册：[https://github.com/sysown/proxysql/wiki][https_github.com_sysown_proxysql_wiki]

### ProxySQL安装后生成的文件 ###

/etc/init.d/proxysql            #此为服务脚本存放在init.d目录下所以需要使用service命令去启动他
    /etc/proxysql.cnf
    /usr/bin/proxysql
    /usr/share/proxysql/tools/proxysql_galera_checker.sh
    /usr/share/proxysql/tools/proxysql_galera_writer.pl

### ProxySQL所使用的端口 ###

ProxySQL所使用的端口为6032和6033  
6032:用来配置ProxySQL，是个管理接口  
6033:用来被远程用户连接端口

### ProxySQL内置数据库 ###

以上这些库中主要配置的库为main库，里面存放了ProxySQL的各种配置。

### ProxySQL main库内的表 ###

main库中的表分为runtime开头和非runtime开头  
runtime开头为运行时的设置  
非runtime开头为需要设置的配置  
所有的配置修改后需要执行命令才能加载到runtime生效

LOAD ... TO RUNTIME

所有的配置修改后需要执行命令才能永久保存

SAVE ... TO DISK

### 日志查看 ###

查看read\_only和replication\_log的监控日志

MySQL [(none)]> select * from mysql_server_read_only_log;
    Empty set (0.00 sec)
    
    MySQL [(none)]> select * from mysql_server_replication_lag_log;
    Empty set (0.00 sec)

## ProxySQL实现读写分离 ##

ProxySQL在实现读写分离之前先要实现主从复制的共功能  
本实验总计使用4台主机，详细配置如下

<table> 
 <thead> 
  <tr> 
   <th style="text-align:left;">主机</th> 
   <th style="text-align:left;">ip地址</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td style="text-align:left;">Client</td> 
   <td style="text-align:left;">192.168.73.113</td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">ProxySQL</td> 
   <td style="text-align:left;">192.168.73.112</td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Master</td> 
   <td style="text-align:left;">192.168.73.110</td> 
  </tr> 
  <tr> 
   <td style="text-align:left;">Slave</td> 
   <td style="text-align:left;">192.168.73.111</td> 
  </tr> 
 </tbody> 
</table>

注意事项：在实现主从复制时从节点在配置文件中必须要设置read\_only，这是ProxySQL区分是用来作为读服务器还是写服务器的依据

--------------------

### 一、实现主从复制 ###

#### 主节点配置 ####

1.修改配置文件

[root@Master ~]# vim /etc/my.cnf
    [mysqld]
    server-id=1
    log-bin
    binlog-format=row

2.启动MySQL服务

[root@Master ~]# systemctl start mariadb
    [root@Master ~]# mysql -e "SHOW MASTER LOGS;"
    +--------------------+-----------+
    | Log_name           | File_size |
    +--------------------+-----------+
    | mariadb-bin.000001 |       245 |
    +--------------------+-----------+

3.创建用来复制的账号

[root@Master ~]# mysql -e "GRANT REPLICATION SLAVE ON *.* TO 'repluser'@'192.168.73.%' IDENTIFIED BY 'centos';"

#### 从节点配置 ####

1.修改配置文件

[root@Slave ~]# vim /etc/my.cnf
    [mysqld]
    server-id=2
    log-bin
    binlog-format=row
    read-only               #必须写

2.启动数据库服务

[root@Slave ~]# systemctl start mariadb

3.写入CHANGE MASTSER TO信息

MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='192.168.73.110', MASTER_USER='repluser',MASTER_PASSWORD='centos',MASTER_PORT=3306,MASTER_LOG_FILE='mariadb-bin.000001',MASTER_LOG_POS=245;
    Query OK, 0 rows affected (0.00 sec)

4.启动复制线程

MariaDB [(none)]> START SLAVE;
    Query OK, 0 rows affected (0.00 sec)

5.查看状态

MariaDB [(none)]> SHOW SLAVE STATUS\G;
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 192.168.73.110
                      Master_User: repluser
                      Master_Port: 3306
                    Connect_Retry: 60
                  Master_Log_File: mariadb-bin.000001
              Read_Master_Log_Pos: 402
                   Relay_Log_File: mariadb-relay-bin.000002
                    Relay_Log_Pos: 688
            Relay_Master_Log_File: mariadb-bin.000001
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes

#### 测试 ####

1.主节点导入数据库

2.从节点查看

主从复制配置完毕

### 二、在ProxySQL上配置读写分离 ###

1.在ProxySQL主机上配置yum源

[root@ProxySQL ~]# vim /etc/yum.repos.d/proxysql.repo
    [proxysql_repo] 
    name= ProxySQL YUM repository 
    baseurl=http://repo.proxysql.com/ProxySQL/proxysql-1.4.x/centos/\$releasever 
    gpgcheck=1
    gpgkey=http://repo.proxysql.com/ProxySQL/repo_pub_key

2.安装ProxySQL和mariadb客户端  
ProxySQL内置了一个轻量级的数据库，所以需要有MySQL客户端连上去对其进行配置

[root@ProxySQL ~]# yum install proxysql mariadb -y

3.启动ProxySQL服务

[root@ProxySQL ~]# service proxysql start
    Starting ProxySQL: 2019-05-08 14:03:07 [INFO] Using config file /etc/proxysql.cnf
    DONE!

4.连接管理端口

[root@ProxySQL ~]# mysql -uadmin -padmin -P6032 -h127.0.0.1
    Welcome to the MariaDB monitor.  Commands end with ; or \g.
    Your MySQL connection id is 1
    Server version: 5.5.30 (ProxySQL Admin Module)
    
    Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
    
    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

5.将MySQL主从服务器信息添加入mysql\_servers表中  
先将主从服务器存放在同一组内，等指定好读写规则后，系统会根据配置文件中的read-only值自动将其分别添加至读组和写组。

MySQL [(none)]> INSERT INTO mysql_servers(hostgroup_id,hostname,port) VALUES (10,'192.168.73.110',3306);
    Query OK, 1 row affected (0.00 sec)
    
    MySQL [(none)]> INSERT INTO mysql_servers(hostgroup_id,hostname,port) VALUES (10,'192.168.73.111',3306);
    Query OK, 1 row affected (0.00 sec)
    
    MySQL [(none)]> SELECT * FROM mysql_servers
        -> ;
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    | hostgroup_id | hostname       | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    | 10           | 192.168.73.110 | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
    | 10           | 192.168.73.111 | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    2 rows in set (0.00 sec)

6.在MySQL服务器的主节点上为ProxySQL添加账号用来查看MySQL节点是主还是从

[root@Master ~]# mysql -e "GRANT REPLICATION SLAVE ON *.* TO 'monitor'@'192.168.73.%' IDENTIFIED BY 'centos';"

7.在Proxy上配置监控账号

MySQL [(none)]> SET mysql-monitor_username='monitor';
    Query OK, 1 row affected (0.00 sec)
    
    MySQL [(none)]> SET mysql-monitor_password='centos';
    Query OK, 1 row affected (0.00 sec)

8.将配置加载至内存，将配置保存至磁盘

MySQL [(none)]> LOAD MYSQL VARIABLES TO RUNTIME;
    Query OK, 0 rows affected (0.00 sec)
    
    MySQL [(none)]> SAVE MYSQL VARIABLES TO DISK;
    Query OK, 97 rows affected (0.00 sec)

9.测试  
9.1查看连接状态

MySQL [(none)]> select * from mysql_server_connect_log;
    +----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
    | hostname       | port | time_start_us    | connect_success_time_us | connect_error                                                           |
    +----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
    | 192.168.73.110 | 3306 | 1557296528658352 | 0                       | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.111 | 3306 | 1557296648056186 | 0                       | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.110 | 3306 | 1557296649025169 | 0                       | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.110 | 3306 | 1557296708057600 | 0                       | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.111 | 3306 | 1557296708872496 | 0                       | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.110 | 3306 | 1557296758752550 | 2763                    | NULL                                                                    |  #此前由于没有创建监控账号所以连接一直失败
    | 192.168.73.111 | 3306 | 1557296759862679 | 3205                    | NULL                                                                    |
    | 192.168.73.110 | 3306 | 1557296818752346 | 1014                    | NULL                                                                    |
    | 192.168.73.111 | 3306 | 1557296819498108 | 3120                    | NULL                                                                    |
    | 192.168.73.110 | 3306 | 1557296878752978 | 3245                    | NULL                                                                    |
    | 192.168.73.111 | 3306 | 1557296879410404 | 3063                    | NULL                                                                    |
    +----------------+------+------------------+-------------------------+-------------------------------------------------------------------------+
    22 rows in set (0.00 sec)

9.2测试连接ping

MySQL [(none)]> select * from mysql_server_ping_log;
    +----------------+------+------------------+----------------------+-------------------------------------------------------------------------+
    | hostname       | port | time_start_us    | ping_success_time_us | ping_error                                                              |
    +----------------+------+------------------+----------------------+-------------------------------------------------------------------------+
    | 192.168.73.111 | 3306 | 1557296508118738 | 0                    | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    | 192.168.73.110 | 3306 | 1557296508302837 | 0                    | Access denied for user 'monitor'@'192.168.73.112' (using password: YES) |
    
    ...中间省略...
    
    | 192.168.73.110 | 3306 | 1557297088874658 | 675                  | NULL                                                                    |
    | 192.168.73.111 | 3306 | 1557297089037256 | 435                  | NULL                                                                    |
    | 192.168.73.110 | 3306 | 1557297098875954 | 1144                 | NULL                                                                    |
    | 192.168.73.111 | 3306 | 1557297099069333 | 1252                 | NULL                                                                    |
    +----------------+------+------------------+----------------------+-------------------------------------------------------------------------+
    122 rows in set (0.00 sec)
    #已经可以联通

10.设置读写分组

MySQL [(none)]> INSERT INTO mysql_replication_hostgroups VALUES(10,20,"test");
    Query OK, 1 row affected (0.00 sec)
    
    MySQL [(none)]> SELECT * FROM mysql_replication_hostgroups;
    +------------------+------------------+---------+
    | writer_hostgroup | reader_hostgroup | comment |
    +------------------+------------------+---------+
    | 10               | 20               | test    |
    +------------------+------------------+---------+
    1 row in set (0.00 sec)

11.让读写表生效

MySQL [(none)]> LOAD MYSQL SERVERS TO RUNTIME;
    Query OK, 0 rows affected (0.00 sec)

12.查看mysql\_server表此时已经将服务器分组

MySQL [(none)]> SELECT * FROM mysql_servers;
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    | hostgroup_id | hostname       | port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    | 10           | 192.168.73.110 | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
    | 20           | 192.168.73.111 | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              |         |
    +--------------+----------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
    2 rows in set (0.00 sec)

13.保存配置至磁盘

MySQL [(none)]> SAVE MYSQL SERVERS TO DISK;
    Query OK, 0 rows affected (0.02 sec)

至此读写分离配置完毕，接下来需要定义读写分离的规则

### 三、定义读写分离规则 ###

1.在主节点上创建一个账户让客户端连接调度器去访问主从服务器（此处授予的权限较大，实际生产中可以根据需要定义指定的那张表）

[root@Master ~]# mysql -e "GRANT ALL ON *.* TO 'sqluser'@'192.168.73.%' IDENTIFIED BY 'centos';"

2.在ProxySQL服务器上，将sqluser用户添加至mysql\_users表中

MySQL [(none)]> INSERT INTO mysql_users(username,password,default_hostgroup) VALUES ('sqluser','centos',10);
    Query OK, 1 row affected (0.00 sec)

3.查看mysql\_user表信息

4.生效存盘

MySQL [(none)]> load mysql users to runtime;
    Query OK, 0 rows affected (0.00 sec)
    
    MySQL [(none)]> SAVE MYSQL USERS TO DISK;
    Query OK, 0 rows affected (0.00 sec)

5.测试  
目前尚未设置读写路由规则，所有的请求都是发往主节点

[root@Client ~]# mysql -usqluser -pcentos -h192.168.73.112 -P6033 -e "SELECT @@server_id;"
    +-------------+
    | @@server_id |
    +-------------+
    |           1 |
    +-------------+

6.在ProxySQL上定义调度规则

MySQL [(none)]> INSERT INTO mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) VALUES (1,1,'^SELECT.*FOR UPDATE$',10,1),(2,1,'^SELECT',20,1);
    Query OK, 2 rows affected (0.00 sec)

7.查看定义规则

MySQL [(none)]>  SELECT * FROM mysql_query_rules\G;
    *************************** 1. row ***************************
                  rule_id: 1
                   active: 1
                 username: NULL
               schemaname: NULL
                   flagIN: 0
              client_addr: NULL
               proxy_addr: NULL
               proxy_port: NULL
                   digest: NULL
             match_digest: ^SELECT.*FOR UPDATE$
            match_pattern: NULL
     negate_match_pattern: 0
             re_modifiers: CASELESS
                  flagOUT: NULL
          replace_pattern: NULL
    destination_hostgroup: 10
                cache_ttl: NULL
                reconnect: NULL
                  timeout: NULL
                  retries: NULL
                    delay: NULL
        next_query_flagIN: NULL
           mirror_flagOUT: NULL
         mirror_hostgroup: NULL
                error_msg: NULL
                   OK_msg: NULL
              sticky_conn: NULL
                multiplex: NULL
                      log: NULL
                    apply: 1
                  comment: NULL
    *************************** 2. row ***************************
                  rule_id: 2
                   active: 1
                 username: NULL
               schemaname: NULL
                   flagIN: 0
              client_addr: NULL
               proxy_addr: NULL
               proxy_port: NULL
                   digest: NULL
             match_digest: ^SELECT
            match_pattern: NULL
     negate_match_pattern: 0
             re_modifiers: CASELESS
                  flagOUT: NULL
          replace_pattern: NULL
    destination_hostgroup: 20
                cache_ttl: NULL
                reconnect: NULL
                  timeout: NULL
                  retries: NULL
                    delay: NULL
        next_query_flagIN: NULL
           mirror_flagOUT: NULL
         mirror_hostgroup: NULL
                error_msg: NULL
                   OK_msg: NULL
              sticky_conn: NULL
                multiplex: NULL
                      log: NULL
                    apply: 1
                  comment: NULL
    2 rows in set (0.00 sec)

8.生效存盘

MySQL [(none)]> LOAD MYSQL QUERY RULES TO RUNTIME;
    Query OK, 0 rows affected (0.00 sec)
    
    MySQL [(none)]> SAVE MYSQL QUERY RULES TO DISK;
    Query OK, 0 rows affected (0.00 sec)

### 四、在Client端测试 ###

1.查询操作

[root@Client ~]# mysql -usqluser -pcentos -h192.168.73.112 -P6033 -e "SELECT @@server_id;"
    +-------------+
    | @@server_id |
    +-------------+
    |           2 |
    +-------------+

2.写操作

[root@Client ~]# mysql -usqluser -pcentos -h192.168.73.112 -P6033 -e "BEGIN;INSERT hellodb.teachers VALUE(5,'Long',30,'M');SELECT @@server_id;commit;"
    +-------------+
    | @@server_id |
    +-------------+
    |           1 |
    +-------------+

转载于:https://blog.51cto.com/11886307/2391101

[MySQL_ProxySQL]: https://s1.51cto.com/images/blog/201905/08/eabbb020e93a15aedb84739b50d6877b.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=
[https_proxysql.com]: https://proxysql.com/
[https_github.com_sysown_proxysql_wiki]: https://github.com/sysown/proxysql/wiki