ProxySQL实现Mysql读写分离 - 部署手册

ProxySQL是一个高性能的MySQL中间件，拥有强大的规则引擎。ProxySQL是用C++语言开发的，也是percona推的一款中间件，虽然也是一个轻量级产品，但性能很好(据测试，能处理千亿级的数据)，功能也足够，能满足中间件所需的绝大多数功能。

ProxySQL具备了很多优质特性，具体总结如下:
-> 连接池，而且是multiplexing
-> 主机和用户的最大连接数限制
-> 自动下线后端DB
    -> 延迟超过阀值
    ->  ping 延迟超过阀值
    ->  网络不通或宕机
-> 强大的规则路由引擎
    -> 实现读写分离
    -> 查询重写
    -> sql流量镜像
-> 支持prepared statement
-> 支持Query Cache
-> 支持负载均衡，与gelera结合自动failover
-> 可定制基于用户、基于schema、基于语句的规则对SQL语句进行路由。换句话说，规则很灵活。基于schema和与语句级的规则，可以实现简单的sharding。
-> 可缓存查询结果。虽然ProxySQL的缓存策略比较简陋，但实现了基本的缓存功能，绝大多数时候也够用了。此外，作者已经打算实现更丰富的缓存策略。
-> 监控后端节点。ProxySQL可以监控后端节点的多个指标，包括：ProxySQL和后端的心跳信息，后端节点的read-only/read-write，slave和master的数据同步延迟性(replication lag)。

ProxySQL是一个能实实在在用在生产环境的MySQL中间件，可以实现读写分离，支持 Query 路由功能，支持动态指定某个 SQL 进行 cache，支持动态加载配置、故障切换和一些 SQL的过滤功能。还有一些同类产品比如 DBproxy、MyCAT、OneProxy 等。但经过反复对比和测试之后，还是觉得ProxySQL是一款性能不谙，靠谱稳定的MySQL 中间件产品 ！

 ProxySQL+Mysql实现数据库读写分离实战记录 

1. 基础环境准备

172.16.60.212    mysql-master      安装Mysql5.7
172.16.60.213    mysql-slave       安装Mysql5.7
172.16.60.214    mysql-proxy       安装ProxySQL，Mysql-client

1) 三个节点各自设置主机名
[root@mysql-master ~]# hostnamectl --static set-hostname mysql-master
[root@mysql-master ~]# hostname
mysql-master

[root@mysql-slave ~]# hostnamectl --static set-hostname mysql-slave
[root@mysql-slave ~]# hostname
mysql-slave

[root@mysql-proxy ~]# hostnamectl --static set-hostname mysql-proxy
[root@mysql-proxy ~]# hostname
mysql-proxy

2) 三个节点都要绑定hosts
[root@mysql-master ~]# cat /etc/hosts
.........
172.16.60.212    mysql-master
172.16.60.213    mysql-slave
172.16.60.214    mysql-proxy

3）三个节点都关闭selinux和iptables防火墙 (为了实验方面，线上环境可以打开，允许3306端口规则)
[root@mysql-master ~]# setenforce 0
[root@mysql-master ~]# cat /etc/sysconfig/selinux |grep "SELINUX=disabled"
SELINUX=disabled

[root@mysql-master ~]# iptables -F
[root@mysql-master ~]# systemctl disable firewalld
[root@mysql-master ~]# systemctl stop firewalld
[root@mysql-master ~]# firewall-cmd --state
not running

2. 安装Mysql 5.7  (在mysql-master 和 mysql-slave节点)

在两个mysql节点机上使用yum方式安装Mysql5.7，参考：https://www.cnblogs.com/kevingrace/p/8340690.html

安装MySQL yum资源库
[root@mysql-master ~]# yum localinstall https://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm

安装MySQL 5.7
[root@mysql-master ~]# yum install -y mysql-community-server

启动MySQL服务器和MySQL的自动启动
[root@mysql-master ~]# systemctl start mysqld.service
[root@mysql-master ~]# systemctl enable mysqld.service

设置登录密码
由于MySQL从5.7开始不允许首次安装后使用空密码进行登录！为了加强安全性，系统会随机生成一个密码以供管理员首次登录使用，
这个密码记录在/var/log/mysqld.log文件中，使用下面的命令可以查看此密码：
[root@mysql-master ~]# cat /var/log/mysqld.log|grep 'A temporary password'
2019-01-11T05:53:17.824073Z 1 [Note] A temporary password is generated for root@localhost: TaN.k:*Qw2xs

使用上面查看的密码TaN.k:*Qw2xs 登录mysql，并重置密码为123456
[root@mysql-master ~]# mysql -p                 #输入默认的密码：TaN.k:*Qw2xs
.............
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)

mysql> set password=password("123456");
Query OK, 0 rows affected, 1 warning (0.00 sec)

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

查看mysql版本
[root@mysql-master ~]# mysql -p123456
........
mysql> select version();
+-----------+
| version() |
+-----------+
| 5.7.24    |
+-----------+
1 row in set (0.00 sec)

=====================================================================
温馨提示
mysql5.7通过上面默认安装后，执行语句可能会报错：
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

这个报错与Mysql 密码安全策略validate_password_policy的值有关，validate_password_policy可以取0、1、2三个值：
解决办法：
set global validate_password_policy=0;
set global validate_password_length=1;

3. 配置Mysql基于GTID的主从同步  (在mysql-master 和 mysql-slave节点)

由于这两台节点机之前做过别的实验，为了保证数据环境干净，可以删除/var/lib/mysql，然后再次重启mysqld即可!
# systemctl stop mysqld
# rm -rf /var/lib/mysql
# systemctl start mysqld

这样操作后，mysql数据库就等于重新初始化了一次，之前的数据环境全部被干掉了，密码也是初始化后的随机密码
如下查看初始密码
# cat /var/log/mysqld.log|grep 'A temporary password'

然后再进行密码重置等操作，这里就不赘述了，在前面安装mysql的时候已经提到过了。
==================================================================

1) mysql-master 作为主数据库节点，其my.cnf配置为:
[root@mysql-master ~]# >/etc/my.cnf
[root@mysql-master ~]# vim /etc/my.cnf
[mysqld]
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

#GTID:
server_id = 1
gtid_mode = on
enforce_gtid_consistency = on

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

#relay log
skip_slave_start = 1

配置完成之后，别忘了重启Mysql
[root@mysql-master ~]# systemctl restart mysqld

查看一下master状态， 发现多了一项"Executed_Gtid_Set "
mysql> show master status;
+-------------------+----------+--------------+------------------+------------------------------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                        |
+-------------------+----------+--------------+------------------+------------------------------------------+
| master-bin.000002 |      550 |              |                  | 88d43a34-1ec8-11e9-b0b5-00505688047c:1-2 |
+-------------------+----------+--------------+------------------+------------------------------------------+
1 row in set (0.00 sec)

mysql> show global variables like '%uuid%';
+---------------+--------------------------------------+
| Variable_name | Value                                |
+---------------+--------------------------------------+
| server_uuid   | 88d43a34-1ec8-11e9-b0b5-00505688047c |
+---------------+--------------------------------------+
1 row in set (0.00 sec)

mysql> show global variables like '%gtid%';
+----------------------------------+------------------------------------------+
| Variable_name                    | Value                                    |
+----------------------------------+------------------------------------------+
| binlog_gtid_simple_recovery      | ON                                       |
| enforce_gtid_consistency         | ON                                       |
| gtid_executed                    | 88d43a34-1ec8-11e9-b0b5-00505688047c:1-2 |
| gtid_executed_compression_period | 1000                                     |
| gtid_mode                        | ON                                       |
| gtid_owned                       |                                          |
| gtid_purged                      |                                          |
| session_track_gtids              | OFF                                      |
+----------------------------------+------------------------------------------+
8 rows in set (0.00 sec)

主库执行从库复制授权
mysql> grant replication slave,replication client on *.* to slave@'172.16.60.213' identified by "slave@123";
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)

mysql> show grants for slave@'172.16.60.213';
+-------------------------------------------------------------------------------+
| Grants for slave@172.16.60.213                                                |
+-------------------------------------------------------------------------------+
| GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'172.16.60.213' |
+-------------------------------------------------------------------------------+
1 row in set (0.00 sec)

在主数据库机器上创建一个测试库kevin（为了测试效果）
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

mysql> CREATE DATABASE kevin CHARACTER SET utf8 COLLATE utf8_general_ci;
Query OK, 1 row affected (0.01 sec)

mysql> use kevin;
Database changed
mysql> create table if not exists haha (id int(10) PRIMARY KEY AUTO_INCREMENT,name varchar(50) NOT NULL);
Query OK, 0 rows affected (0.27 sec)

mysql> insert into kevin.haha values(1,"congcong"),(2,"huihui"),(3,"grace");
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from kevin.haha;
+----+----------+
| id | name     |
+----+----------+
|  1 | congcong |
|  2 | huihui   |
|  3 | grace    |
+----+----------+
3 rows in set (0.00 sec)

==========================================================================
2) 从数据库172.16.60.206的操作
my.cnf文件里GTID复制的配置内容如下：
与主服务器配置大概一致，除了server_id不一致外，从服务器还可以在配置文件里面添加："read_only＝on" ,
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；

[root@mysql-slave ~]# > /etc/my.cnf
[root@mysql-slave ~]# vim /etc/my.cnf
[mysqld]
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

#GTID:
server_id = 2
gtid_mode = on
enforce_gtid_consistency = on

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

#relay log
skip_slave_start = 1
read_only = on

配置完成之后，别忘了重启Mysql
[root@mysql-slave ~]# systemctl restart mysqld

接着登录mysql，做主从同步
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

在从数据库里，使用change master 配置主从复制
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> change master to master_host='172.16.60.212',master_user='slave',master_password='slave@123',master_auto_position=1;
Query OK, 0 rows affected, 2 warnings (0.50 sec)

mysql> start slave;
Query OK, 0 rows affected (0.05 sec)

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 172.16.60.212
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: master-bin.000002
          Read_Master_Log_Pos: 1753
               Relay_Log_File: mysql-slave-relay-bin.000002
                Relay_Log_Pos: 1968
        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: 1753
              Relay_Log_Space: 2181
              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: 88d43a34-1ec8-11e9-b0b5-00505688047c
             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: 88d43a34-1ec8-11e9-b0b5-00505688047c:1-7
            Executed_Gtid_Set: 872832c0-1ec8-11e9-84a5-005056880888:1-2,
88d43a34-1ec8-11e9-b0b5-00505688047c:1-7
                Auto_Position: 1
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

ERROR:
No query specified

接着查看从数据库的数据，发现kevin库已经同步过来了!
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| kevin              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> select * from kevin.haha;
+----+----------+
| id | name     |
+----+----------+
|  1 | congcong |
|  2 | huihui   |
|  3 | grace    |
+----+----------+
3 rows in set (0.00 sec)

查看从数据库的gtid信息
mysql> show global variables like '%gtid%';
+----------------------------------+-------------------------------------------------------------------------------------+
| Variable_name                    | Value                                                                               |
+----------------------------------+-------------------------------------------------------------------------------------+
| binlog_gtid_simple_recovery      | ON                                                                                  |
| enforce_gtid_consistency         | ON                                                                                  |
| gtid_executed                    | 872832c0-1ec8-11e9-84a5-005056880888:1-2,
88d43a34-1ec8-11e9-b0b5-00505688047c:1-11 |
| gtid_executed_compression_period | 1000                                                                                |
| gtid_mode                        | ON                                                                                  |
| gtid_owned                       |                                                                                     |
| gtid_purged                      |                                                                                     |
| session_track_gtids              | OFF                                                                                 |
+----------------------------------+-------------------------------------------------------------------------------------+
8 rows in set (0.00 sec)

3) 然后回到主数据库中查看master状态
mysql> show slave hosts;
+-----------+------+------+-----------+--------------------------------------+
| Server_id | Host | Port | Master_id | Slave_UUID                           |
+-----------+------+------+-----------+--------------------------------------+
|         2 |      | 3306 |         1 | 872832c0-1ec8-11e9-84a5-005056880888 |
+-----------+------+------+-----------+--------------------------------------+
1 row in set (0.00 sec)

通过上面一系列配置，则mysql基于GTID的主从复制环境就部署好了。

4) 下面开始验证：
在172.16.60.212的主数据库里插入新数据
mysql> insert into kevin.haha values(10,"heifei"),(11,"huoqiu"),(12,"chengxihu");
Query OK, 3 rows affected (0.05 sec)
Records: 3  Duplicates: 0  Warnings: 0

到172.16.60.213的从数据库里查看，发现已经同步过来了
mysql> select * from kevin.haha;
+----+-----------+
| id | name      |
+----+-----------+
|  1 | congcong  |
|  2 | huihui    |
|  3 | grace     |
| 10 | heifei    |
| 11 | huoqiu    |
| 12 | chengxihu |
+----+-----------+
6 rows in set (0.00 sec)

4. 安装配置ProxySQL，实现读写分离 (在mysql-proxy节点)

也可以参考另一篇博文https://www.cnblogs.com/kevingrace/p/5569652.html，这篇文档里已介绍了利用proxysql实现读写分离操作 (一主两从，一写两读模式)。

-  安装mysql客户端，用于在本机连接到ProxySQL的管理接口

[root@mysql-proxy ~]# vim /etc/yum.repos.d/mariadb.repo
[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.3.5/centos6-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

安装mysql-clinet客户端
[root@mysql-proxy ~]# yum install -y MariaDB-client

--------------------------------------------------------------------------------------------------------------------------------------------------------
如果遇到报错：
Error: MariaDB-compat conflicts with 1:mariadb-libs-5.5.60-1.el7_5.x86_64
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest

解决办法：
[root@mysql-proxy ~]# rpm -qa|grep mariadb*
mariadb-libs-5.5.56-2.el7.x86_64
[root@mysql-proxy ~]# rpm -e mariadb-libs-5.5.56-2.el7.x86_64 --nodeps
[root@mysql-proxy ~]# yum install -y MariaDB-client

-  安装proxysql

proxysql的rpm包下载地址: https://pan.baidu.com/s/1S1_b5DKVCpZSOUNmtCXrrg
提取密码: 5t1c

[root@mysql-proxy ~]# wget https://github.com/sysown/proxysql/releases/download/v1.4.8/proxysql-1.4.8-1-centos7.x86_64.rpm
[root@mysql-proxy ~]# rpm -ivh proxysql-1.4.8-1-centos7.x86_64.rpm --force

配置文件详解
[root@mysql-proxy ~]# egrep -v "^#|^$" /etc/proxysql.cnf
datadir="/var/lib/proxysql"                                   #数据目录
admin_variables=
{
        admin_credentials="admin:admin"                       #连接管理端的用户名与密码
        mysql_ifaces="0.0.0.0:6032"                           #管理端口，用来连接proxysql的管理数据库
}
mysql_variables=
{
        threads=4                                             #指定转发端口开启的线程数量
        max_connections=2048
        default_query_delay=0
        default_query_timeout=36000000
        have_compress=true
        poll_timeout=2000
        interfaces="0.0.0.0:6033"                             #指定转发端口，用于连接后端mysql数据库的，相当于代理作用
        default_schema="information_schema"
        stacksize=1048576
        server_version="5.5.30"                               #指定后端mysql的版本
        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=
(
)

# 在部署过程中，最好使用官方推荐的方式来配置proxy sql

-  启动服务并查看

[root@mysql-proxy ~]# /etc/init.d/proxysql start
Starting ProxySQL: DONE!

[root@mysql-proxy ~]# ss -lntup|grep proxy
tcp    LISTEN     0      128       *:6032                  *:*                   users:(("proxysql",pid=2943,fd=24))
tcp    LISTEN     0      128       *:6033                  *:*                   users:(("proxysql",pid=2943,fd=22))
tcp    LISTEN     0      128       *:6033                  *:*                   users:(("proxysql",pid=2943,fd=21))
tcp    LISTEN     0      128       *:6033                  *:*                   users:(("proxysql",pid=2943,fd=20))
tcp    LISTEN     0      128       *:6033                  *:*                   users:(("proxysql",pid=2943,fd=19))

可以看出转发端口6033是启动了四个线程

-  在mysql-master主数据库节点上执行：(只需master执行即可，会复制给slave从数据库)

mysql> GRANT ALL ON *.* TO 'proxysql'@'172.16.60.%' IDENTIFIED BY '123456';
Query OK, 0 rows affected, 1 warning (0.03 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.04 sec)

-  proxysql默认数据库说明

[root@mysql-proxy ~]# mysql -uadmin -padmin -h127.0.0.1 -P6032
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.

MySQL [(none)]> 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 (0.001 sec)

ProxySQL提供了几个库，每个库都有各自的意义；
-> main内存配置数据库，表里存放后端db实例、用户验证、路由规则等信息。表名以 runtime_开头的表示proxysql当前运行的配置内容，
   不能通过dml语句修改，只能修改对应的不以 runtime_ 开头的（在内存）里的表，然后 LOAD 使其生效， SAVE 使其存到硬盘以供下次重启加载。
-> disk 是持久化到硬盘的配置，sqlite数据文件。
-> stats 是proxysql运行抓取的统计信息，包括到后端各命令的执行次数、流量、processlist、查询种类汇总/执行时间等等。
-> monitor 库存储 monitor 模块收集的信息，主要是对后端db的健康/延迟检查。

-  proxysql的配置系统

ProxySQL具有一个复杂但易于使用的配置系统，可以满足以下需求：
-> 允许轻松动态更新配置（这是为了让ProxySQL用户可以在需要零宕机时间配置的大型基础架构中使用它）。与MySQL兼容的管理界面可用于此目的。
-> 允许尽可能多的配置项目动态修改，而不需要重新启动ProxySQL进程
-> 可以毫不费力地回滚无效配置
-> 这是通过多级配置系统实现的，其中设置从运行时移到内存，并根据需要持久保存到磁盘。

3级配置由以下几层组成:
+-------------------------+
|         RUNTIME         |
+-------------------------+
       /|\          |
        |           |
    [1] |       [2] |
        |          \|/
+-------------------------+
|         MEMORY          |
+-------------------------+ _
       /|\          |      |\
        |           |        \
    [3] |       [4] |         \ [5]
        |          \|/         \
+-------------------------+  +-------------------------+
|          DISK           |  |       CONFIG FILE       |
+-------------------------+  +-------------------------+

可以参考官方文章：https://github.com/sysown/proxysql/wiki/Configuring-ProxySQL

-  配置proxysql管理用户

MySQL [(none)]> show tables;
+--------------------------------------------+
| tables                                     |
+--------------------------------------------+
| global_variables                           |
| mysql_collations                           |
| mysql_group_replication_hostgroups         |
| mysql_query_rules                          |
| mysql_query_rules_fast_routing             |
| mysql_replication_hostgroups               |
| mysql_servers                              |
| mysql_users                                |
| proxysql_servers                           |
| runtime_checksums_values                   |
| runtime_global_variables                   |
| 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_scheduler                          |
| scheduler                                  |
+--------------------------------------------+
20 rows in set (0.000 sec)

下面使用insert into语句来动态配置（插入语句里使用主机名或ip都可以），而可以不需要重启!!!

MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(1,'mysql-master','3306',1,'Write Group');
Query OK, 1 row affected (0.000 sec)

MySQL [(none)]> insert into mysql_servers(hostgroup_id,hostname,port,weight,comment) values(2,'mysql-slave','3306',1,'Read Group');
Query OK, 1 row affected (0.000 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     |
+--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+-------------+
| 1            | mysql-master | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              | Write Group |
| 2            | mysql-slave  | 3306 | ONLINE | 1      | 0           | 1000            | 0                   | 0       | 0              | Read Group  |
+--------------+--------------+------+--------+--------+-------------+-----------------+---------------------+---------+----------------+-------------+
2 rows in set (0.000 sec)

接下来将刚刚在mysql客户端创建的用户写入到proxy sql主机的mysql_users表中，它也是用于proxysql客户端访问数据库，默认组是写组，
当读写分离规则出现问题时，它会直接访问默认组的数据库。

MySQL [(none)]> INSERT INTO mysql_users(username,password,default_hostgroup) VALUES ('proxysql','123456',1);
Query OK, 1 row affected (0.000 sec)

MySQL [(none)]> select * from mysql_users;
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| username | password | active | use_ssl | default_hostgroup | default_schema | schema_locked | transaction_persistent | fast_forward | backend | frontend | max_connections |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
| proxysql | 123456   | 1      | 0       | 1                 | NULL           | 0             | 1                      | 0            | 1       | 1        | 10000           |
+----------+----------+--------+---------+-------------------+----------------+---------------+------------------------+--------------+---------+----------+-----------------+
1 row in set (0.000 sec)

-  在mysql-master主数据库节点上添加监控的用户：(只需master执行即可，会复制给slave从数据库)

mysql> GRANT SELECT ON *.* TO 'monitor'@'172.16.60.%' IDENTIFIED BY 'monitor';
Query OK, 0 rows affected, 1 warning (0.03 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.03 sec)

-  在mysql-proxy节点上配置监控用户

MySQL [(none)]> set mysql-monitor_username='monitor';
Query OK, 1 row affected (0.001 sec)

MySQL [(none)]> set mysql-monitor_password='monitor';
Query OK, 1 row affected (0.000 sec)

-  配置proxysql的转发规则

MySQL [(none)]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) values(1,1,'^SELECT.*FOR UPDATE$',1,1);
Query OK, 1 row affected (0.000 sec)

MySQL [(none)]> insert into mysql_query_rules(rule_id,active,match_digest,destination_hostgroup,apply) values(2,1,'^SELECT',2,1);
Query OK, 1 row affected (0.000 sec)

MySQL [(none)]> select rule_id,active,match_digest,destination_hostgroup,apply from mysql_query_rules;
+---------+--------+----------------------+-----------------------+-------+
| rule_id | active | match_digest         | destination_hostgroup | apply |
+---------+--------+----------------------+-----------------------+-------+
| 1       | 1      | ^SELECT.*FOR UPDATE$ | 1                     | 1     |
| 2       | 1      | ^SELECT              | 2                     | 1     |
+---------+--------+----------------------+-----------------------+-------+
2 rows in set (0.000 sec)

以上配置后，可以得知：
-> 配置查询select的请求转发到hostgroup_id=2组上（读组）;
-> 征对select * from table_name  for update这样的修改语句，我们是需要将请求转到写组，也就是hostgroup_id=1;
-> 对于其它没有被规则匹配的请求全部转发到默认的组（mysql_users表中default_hostgroup）;

- 更新配置到RUNTIME中

由上面的配置系统层级关系可以得知所有进来的请求首先是经过RUNTIME层

MySQL [(none)]> load mysql users to runtime;
Query OK, 0 rows affected (0.001 sec)

MySQL [(none)]> load mysql servers to runtime;
Query OK, 0 rows affected (0.004 sec)

MySQL [(none)]> load mysql query rules to runtime;
Query OK, 0 rows affected (0.001 sec)

MySQL [(none)]> load mysql variables to runtime;
Query OK, 0 rows affected (0.001 sec)

MySQL [(none)]> load admin variables to runtime;
Query OK, 0 rows affected (0.001 sec)

-  将所有配置保存至磁盘上
所有配置数据保存到磁盘上，也就是永久写入/var/lib/proxysql/proxysql.db这个文件中

MySQL [(none)]> save mysql users to disk;
Query OK, 0 rows affected (0.103 sec)

MySQL [(none)]> save mysql servers to disk;
Query OK, 0 rows affected (0.273 sec)

MySQL [(none)]> save mysql query rules to disk;
Query OK, 0 rows affected (0.320 sec)

MySQL [(none)]> save mysql variables to disk;
Query OK, 94 rows affected (0.084 sec)

MySQL [(none)]> save admin variables to disk;
Query OK, 31 rows affected (0.059 sec)

MySQL [(none)]> load mysql users to runtime;
Query OK, 0 rows affected (0.001 sec)

-  测试读写分离

通过转发端口连接数据库，这时连接到的才是我们真正需要的数据 （注意转发端口是6033）
[root@mysql-proxy ~]# mysql -uproxysql -p123456 -h 127.0.0.1 -P 6033
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.5.30 (ProxySQL)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| kevin              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.002 sec)

MySQL [(none)]> 

这时发现的才是我们真正的数据库
MySQL [(none)]> select * from kevin.haha;
+----+-----------+
| id | name      |
+----+-----------+
|  1 | congcong  |
|  2 | huihui    |
|  3 | grace     |
| 10 | heifei    |
| 11 | huoqiu    |
| 12 | chengxihu |
+----+-----------+
6 rows in set (0.001 sec)

下载开始创建数据与表，测试读写分离情况
MySQL [(none)]> delete from kevin.haha where id > 9;
Query OK, 3 rows affected (0.218 sec)

MySQL [(none)]> create database test_proxysql;
Query OK, 1 row affected (0.027 sec)

MySQL [(none)]> select * from kevin.haha;
+----+----------+
| id | name     |
+----+----------+
|  1 | congcong |
|  2 | huihui   |
|  3 | grace    |
+----+----------+
3 rows in set (0.001 sec)

MySQL [(none)]> insert into kevin.haha values(10,"heifei"),(11,"huoqiu"),(12,"chengxihu");
Query OK, 3 rows affected (0.045 sec)
Records: 3  Duplicates: 0  Warnings: 0

MySQL [(none)]> select * from kevin.haha;
+----+-----------+
| id | name      |
+----+-----------+
|  1 | congcong  |
|  2 | huihui    |
|  3 | grace     |
| 10 | heifei    |
| 11 | huoqiu    |
| 12 | chengxihu |
+----+-----------+
6 rows in set (0.001 sec)

MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| kevin              |
| mysql              |
| performance_schema |
| sys                |
| test_proxysql      |
+--------------------+
6 rows in set (0.001 sec)

[root@mysql-proxy ~]# mysql -uproxysql -p123456 -h 127.0.0.1 -P 6033 -e "select @@server_id"
+-------------+
| @@server_id |
+-------------+
|           2 |
+-------------+
[root@mysql-proxy ~]# mysql -uproxysql -p123456 -h 127.0.0.1 -P 6033 -e "select * from kevin.haha"
+----+-----------+
| id | name      |
+----+-----------+
|  1 | congcong  |
|  2 | huihui    |
|  3 | grace     |
| 10 | heifei    |
| 11 | huoqiu    |
| 12 | chengxihu |
+----+-----------+

在proxysql管理端查看读写分离 （注意管理端口是6032）
[root@mysql-proxy ~]# mysql -uadmin -padmin -h127.0.0.1 -P6032
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
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.

MySQL [(none)]> select * from stats_mysql_query_digest;
+-----------+--------------------+----------+--------------------+------------------------------------------------+------------+------------+------------+----------+----------+----------+
| hostgroup | schemaname         | username | digest             | digest_text                                    | count_star | first_seen | last_seen  | sum_time | min_time | max_time |
+-----------+--------------------+----------+--------------------+------------------------------------------------+------------+------------+------------+----------+----------+----------+
| 2         | information_schema | proxysql | 0x3EA85877510AC608 | select * from stats_mysql_query_digest         | 1          | 1548230792 | 1548230792 | 819      | 819      | 819      |
| 1         | information_schema | proxysql | 0xB9EF28C84E4207EC | create database test_proxysql                  | 1          | 1548230738 | 1548230738 | 26859    | 26859    | 26859    |
| 1         | information_schema | proxysql | 0x9316817E8C74BCB2 | insert into kevin.haha values(?,?),(?,?),(?,?) | 1          | 1548230755 | 1548230755 | 44572    | 44572    | 44572    |
| 1         | information_schema | proxysql | 0xF6FA5DFBB674D5FF | delete from kevin.haha where id > ?            | 1          | 1548230729 | 1548230729 | 218165   | 218165   | 218165   |
| 2         | information_schema | proxysql | 0xD8AAAE77FA99AC44 | select * from kevin.haha                       | 4          | 1548230646 | 1548231045 | 3590     | 781      | 1149     |
| 2         | information_schema | proxysql | 0xDA65260DF35B8D13 | select @@server_id                             | 2          | 1548231028 | 1548231030 | 1335     | 578      | 757      |
| 2         | information_schema | proxysql | 0xF8F2DF2E08F87E71 | select * from mysql.kevin                      | 1          | 1548230640 | 1548230640 | 2004     | 2004     | 2004     |
| 1         | information_schema | proxysql | 0x02033E45904D3DF0 | show databases                                 | 2          | 1548230538 | 1548230771 | 2957     | 905      | 2052     |
| 1         | information_schema | proxysql | 0x226CD90D52A2BA0B | select @@version_comment limit ?               | 4          | 1548229930 | 1548231045 | 0        | 0        | 0        |
+-----------+--------------------+----------+--------------------+------------------------------------------------+------------+------------+------------+----------+----------+----------+
9 rows in set (0.002 sec)

从上述结果就可以看出proxysql实现的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!!

整个读写分离的架构配置到此就完成了，但是此架构存在需要优化的地方，那就是此架构存在单点问题。实际生产环境中可采用MHA+ProxySQL+Mysql这类架构解来避免单点故障问题。