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 running2. 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。
来源：oschina
链接：https://my.oschina.net/u/4342956/blog/3919423