Mysql读写分离（mysql-proxy）

MySQL-Proxy是一个处于你的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、查询分析，查询过滤和修改等等。

MySQL-Proxy就是这么一个中间层代理，简单的说，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，可以实现复杂的连接控制和过滤，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机器做为冗余，在应用服务器的连接池配置中配置到多个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，让从库处理SELECT查询。数据库复制被用来把事务性查询导致的变更同步到集群中的从库。

mysql-proxy 命令

• --help-all ———— 用于获取全部帮助信息

• --proxy-address=host:port ———— 代理服务监听的地址和端口

• --admin-address=host:port ———— 管理模块监听的地址和端口

• --proxy-backend-addresses=host:port ———— 后端mysql服务器的地址和端口（主服务器）

• --proxy-read-only-backend-addresses=host:port ———— 后端只读mysql服务器的地址和端口（从服务器）

• --proxy-lua-script=file ———— 完成mysql代理功能的Lua脚本

• --daemon ———— 以守护进程模式启动mysql-proxy

• --defaults-file=/path/to/conf_file_name ———— 默认使用的配置文件路径

• --log-file=/path/to/log_file_name ———— 日志文件名称

• --log-level=level ———— 日志级别

• --log-use-syslog ———— 基于syslog记录日志

• --user=user_name ———— 运行mysql-proxy进程的用户

本文以下内容是在上一篇博客（mysql主从复制）基础上完成。

http://www.cnblogs.com/Eivll0m/p/3776496.html

1.环境及系统软件版本介绍：

系统版本：CentOS 6.3_x86_64

Mysql版本：mysql-5.6.17

mysql-proxy版本：mysql-proxy-0.8.4（下载地址：http://cdn.mysql.com/Downloads/MySQL-Proxy/mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit.tar.gz）

2.部署mysql-proxy，以下操作未经特殊说明，均表示在mysql-prxoy（172.16.10.60）服务器上进行。

2.1检查是否安装了lua包，mysql-proxy需要用到lua脚本，以下表示已经安装过。

# rpm -q lua
lua-5.1.4-4.1.el6.x86_64

2.2创建代理用户

# useradd -r mysql-proxy

2.3下载通用的压缩包mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit.tar.gz（直接解压使用）

# wget http://cdn.mysql.com/Downloads/MySQL-Proxy/mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit.tar.gz
# tar xf mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local
# cd /usr/local/  
# ln -sv mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit mysql-proxy

2.4设置mysql-proxy相关文件权限

chown -R root:mysql-proxy /usr/local/mysql-proxy/*

2.5更新环境变量

# vi /etc/profile.d/mysql-proxy.sh
export PATH=$PATH:/usr/local/mysql-proxy/bin
# . /etc/profile

2.6启动mysql-proxy

# mysql-proxy  --daemon --log-level=debug --log-file=/var/log/mysql-proxy.log --plugins="proxy" --proxy-backend-addresses="172.16.10.72:3306" --proxy-read-only-backend-addresses="172.16.10.61:3306"

2.7检查mysql-proxy是否正常启动

通过命令netstat -antpl|grep mysql-prxoy或tail /var/log/mysql-proxy.log进行查看

2.8在master服务器(172.16.10.72)上创建测试账号

mysql> GRANT ALL ON *.* TO proxy@'172.16.10.%' IDENTIFIED BY '123456';        
Query OK, 0 rows affected (0.22 sec)

mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.03 sec)'

2.9在slave服务器（172.16.10.61）上测试是否能通过代理端口4040 端口连接到 mysql-proxy（以下表示测试成功）

root@mysql_slave ~]# mysql -uproxy -p -h172.16.10.60 -P 4040             
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 456
Server version: 5.6.17-log Source distribution

Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> 

2.10配置读写分离，mysql-proxy 的安装目录中有一个名为rw-splitting.lua的 脚本，通过它可以实现读写分离，路径是/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua。

# ls /usr/local/mysql-proxy/share/doc/mysql-proxy/|grep rw-splitting.lua 
rw-splitting.lua

杀掉当前mysql-proxy进程，然后把lua脚本加入到启动选项里面重新启动mysql-proxy，实现读写分离

# mysql-proxy --daemon --log-level=debug --log-file=/var/log/mysql-proxy.log --plugins="proxy" --proxy-backend-addresses="172.16.10.72:3306" --proxy-read-only-backend-addresses="172.16.10.61:3306" --proxy-lua-script=" /usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"

查看日志

# tail /var/log/mysql-proxy.log 
2014-06-13 16:23:04: (message) added read/write backend: 172.16.10.72:3306
2014-06-13 16:23:04: (message) added read-only backend: 172.16.10.61:3306
2014-06-13 16:40:11: (message) Initiating shutdown, requested from signal handler
2014-06-13 16:40:11: (message) shutting down normally, exit code is: 0
2014-06-13 16:40:17: (debug) chassis-path.c.122: adjusting relative path ( /usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua) to base_dir (/usr/local/mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit). New path: /usr/local/mysql-proxy-0.8.4-linux-glibc2.3-x86-64bit/ /usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua
2014-06-13 16:40:17: (critical) plugin proxy 0.8.4 started
2014-06-13 16:40:17: (debug) max open file-descriptors = 1024
2014-06-13 16:40:17: (message) proxy listening on port :4040
2014-06-13 16:40:17: (message) added read/write backend: 172.16.10.72:3306
2014-06-13 16:40:17: (message) added read-only backend: 172.16.10.61:3306

2.11为mysql-proxy 提供一个管理接口，方便以后随时查看后端mysql 服务器的状态和访问类型，实现管理功能

 

# vi /usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua
function set_error(errmsg)  
    proxy.response = {  
        type = proxy.MYSQLD_PACKET_ERR,  
        errmsg = errmsg or "error"  
    }  
end
function read_query(packet) 
    if packet:byte() ~= proxy.COM_QUERY then  
        set_error("[admin] we only handle text-based queries (COM_QUERY)")  
        return proxy.PROXY_SEND_RESULT  
    end
    local query = packet:sub(2)
    local rows = { } 
    local fields = { }
    if query:lower() == "select * from backends" then 
        fields = {   
            { name = "backend_ndx",   
              type = proxy.MYSQL_TYPE_LONG },
            { name = "address", 
              type = proxy.MYSQL_TYPE_STRING },  
            { name = "state",  
              type = proxy.MYSQL_TYPE_STRING },  
            { name = "type",  
              type = proxy.MYSQL_TYPE_STRING },  
            { name = "uuid",  
              type = proxy.MYSQL_TYPE_STRING },  
            { name = "connected_clients",   
              type = proxy.MYSQL_TYPE_LONG },  
        }
        for i = 1, #proxy.global.backends do 
            local states = {  
                "unknown",  
                "up",  
                "down"  
            }  
            local types = {  
                "unknown",  
                "rw",  
                "ro"  
            }  
            local b = proxy.global.backends[i]
            rows[#rows + 1] = { 
                i,  
                b.dst.name,          -- configured backend address  
                states[b.state + 1], -- the C-id is pushed down starting at 0  
                types[b.type + 1],   -- the C-id is pushed down starting at 0  
                b.uuid,              -- the MySQL Server's UUID if it is managed  
                b.connected_clients  -- currently connected clients  
            }  
        end  
    elseif query:lower() == "select * from help" then  
        fields = {   
            { name = "command",   
              type = proxy.MYSQL_TYPE_STRING },  
            { name = "description",   
              type = proxy.MYSQL_TYPE_STRING },  
        }  
        rows[#rows + 1] = { "SELECT * FROM help", "shows this help" }  
        rows[#rows + 1] = { "SELECT * FROM backends", "lists the backends and their state" }  
    else  
        set_error("use 'SELECT * FROM help' to see the supported commands")  
        return proxy.PROXY_SEND_RESULT  
    end
    proxy.response = { 
        type = proxy.MYSQLD_PACKET_OK,  
        resultset = {  
            fields = fields,  
            rows = rows  
        }  
    }  
    return proxy.PROXY_SEND_RESULT  
end

2.12重新启动mysql-proxy

注，这次启动要添加以下启动选项 ，因为我们添加了额外的插件，把新加功能添加进来,选项如下。

• --plugins=admin  在mysql-proxy启动时加载的插件；

• --admin-username="admin" 运行mysql-proxy进程管理的用户；

• --admin-password="admin" 密码

• --admin-lua-script="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua" 插件使用的配置文件路径；

# killall mysql-proxy
# mysql-proxy --daemon --log-level=debug --log-file=/var/log/mysql-proxy.log --plugins="proxy" --proxy-backend-addresses="172.16.10.72:3306" --proxy-read-only-backend-addresses="172.16.10.61:3306" --proxy-lua-script=" /usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua" --plugins=admin --admin-username="admin" --admin-password="admin" --admin-lua-script="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua" 

查看mysql-proxy是否启

# netstat -antpl|grep mysql
tcp        0      0 0.0.0.0:4040                0.0.0.0:*                   LISTEN      9511/mysql-proxy    
tcp        0      0 0.0.0.0:4041                0.0.0.0:*                   LISTEN      9511/mysql-proxy   #4041为新生成的管理端口

2.13在slave服务器（172.16.10.61）上进行测试，使用管理端口4041 登陆，密码是admin。（测试成功！）

Bye
[root@mysql_slave ~]# mysql -uadmin -p -h172.16.10.60 -P 4041                 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1
Server version: 5.0.99-agent-admin

Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> 

2.14测试是否可以连接

root@mysql_slave ~]# mysql -uadmin -p -h172.16.10.60 -P 4041                 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 1
Server version: 5.0.99-agent-admin

Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> select * from backends;
+-------------+-------------------+---------+------+------+-------------------+
| backend_ndx | address           | state   | type | uuid | connected_clients |
+-------------+-------------------+---------+------+------+-------------------+
|           1 | 172.16.10.72:3306 | unknown | rw   | NULL |                 0 |
|           2 | 172.16.10.61:3306 | unknown | ro   | NULL |                 0 |
+-------------+-------------------+---------+------+------+-------------------+
2 rows in set (0.00 sec)

mysql> 

由于此时没有进行任何操作，所以主从状态都是unknown。

2.15配置启动脚本，并修连接端口（连接mysql-proxy时，原来用的端口是4040，下面修改为3306）

# vi /etc/sysconfig/mysql-proxy
# Options for mysql-proxy  
ADMIN_USER="admin"  
ADMIN_PASSWORD="admin"  
ADMIN_ADDRESS=""  
ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"  
PROXY_ADDRESS="0.0.0.0:3306"  
PROXY_USER="mysql-proxy"  
PROXY_OPTIONS="--daemon --log-level=info --log-file="/var/log/mysql-proxy.log" --plugins=proxy --plugins=admin --proxy-backend-addresses=172.16.10.72:3306 --proxy-read-only-backend-addresses=172.16.10.61:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"

添加sysV脚本

# vi /etc/init.d/mysql-proxy
#!/bin/bash  
#  
# mysql-proxy This script starts and stops the mysql-proxy daemon  
#  
# chkconfig: - 78 30  
# processname: mysql-proxy  
# description: mysql-proxy is a proxy daemon for mysql
# Source function library. 
. /etc/rc.d/init.d/functions
prog="/usr/local/mysql-proxy/bin/mysql-proxy"
# Source networking configuration. 
if [ -f /etc/sysconfig/network ]; then  
    . /etc/sysconfig/network  
fi
# Check that networking is up. 
[ ${NETWORKING} = "no" ] && exit 0
# Set default mysql-proxy configuration. 
ADMIN_USER="admin"  
ADMIN_PASSWD="admin"  
ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"  
PROXY_OPTIONS="--daemon"  
PROXY_PID=/var/run/mysql-proxy.pid  
PROXY_USER="mysql-proxy"
# Source mysql-proxy configuration. 
if [ -f /etc/sysconfig/mysql-proxy ]; then  
    . /etc/sysconfig/mysql-proxy  
fi
RETVAL=0
start() { 
    echo -n $"Starting $prog: "  
    daemon $prog $PROXY_OPTIONS --pid-file=$PROXY_PID --proxy-address="$PROXY_ADDRESS" --user=$PROXY_USER --admin-username="$ADMIN_USER" --admin-lua-script="$ADMIN_LUA_SCRIPT" --admin-password="$ADMIN_PASSWORD"  
    RETVAL=$?  
    echo  
    if [ $RETVAL -eq 0 ]; then  
        touch /var/lock/subsys/mysql-proxy  
    fi  
}
stop() { 
    echo -n $"Stopping $prog: "  
    killproc -p $PROXY_PID -d 3 $prog  
    RETVAL=$?  
    echo  
    if [ $RETVAL -eq 0 ]; then  
        rm -f /var/lock/subsys/mysql-proxy  
        rm -f $PROXY_PID  
    fi  
}  
# See how we were called.  
case "$1" in  
    start)  
        start  
        ;;  
    stop)  
        stop  
        ;;  
    restart)  
        stop  
        start  
        ;;  
    condrestart|try-restart)  
        if status -p $PROXY_PIDFILE $prog >&/dev/null; then  
            stop  
            start  
        fi  
        ;;  
    status)  
        status -p $PROXY_PID $prog  
        ;;  
    *)  
        echo "Usage: $0 {start|stop|restart|reload|status|condrestart|try-restart}"  
        RETVAL=1  
        ;;  
esac
exit $RETVAL

# chmod +x /etc/rc.d/init.d/mysql-proxy
# chkconfig --add mysql-proxy
# chkconfig mysql-proxy on

2.16重启mysql-proxy并查看端口（4040端口已消失）

# service mysql-proxy restart
# netstat -antpl|grep mysql      
tcp        0      0 0.0.0.0:4041                0.0.0.0:*                   LISTEN      12427/mysql-proxy   
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      12427/mysql-proxy  

2.17测试读写分离

执行读写操作

[root@mysql_slave ~]# mysql -uproxy -p -h172.16.10.60 -e "show databases;"     
Enter password: 
+--------------------+
| Database           |
+--------------------+
| information_schema |
| eivll0m            |
| mysql              |
| performance_schema |
| test               |
+--------------------+
[root@mysql_slave ~]# mysql -uproxy -p -h172.16.10.60 -e "create database mydb1;"
Enter password: 

mysql> select * from backends;
+-------------+-------------------+---------+------+------+-------------------+
| backend_ndx | address           | state   | type | uuid | connected_clients |
+-------------+-------------------+---------+------+------+-------------------+
|           1 | 172.16.10.72:3306 | up      | rw   | NULL |                 0 |
|           2 | 172.16.10.61:3306 | unknown | ro   | NULL |                 0 |
+-------------+-------------------+---------+------+------+-------------------+
2 rows in set (0.00 sec)

由于master是支持读写的，所以只发现master状态变为了up是正常现象，要想观看到从的状态，可以执行多次查询。

# mysql -uproxy -p -h172.16.10.60 -e "select user,host from mysql.user"
Enter password: 
+-------+--------------+
| user  | host         |
+-------+--------------+
| root  | 127.0.0.1    |
| proxy | 172.16.10.%  |
| root  | ::1          |
|       | localhost    |
| root  | localhost    |
|       | mysql\_slave |
| root  | mysql\_slave |
+-------+--------------+

mysql> select * from backends;
+-------------+-------------------+-------+------+------+-------------------+
| backend_ndx | address           | state | type | uuid | connected_clients |
+-------------+-------------------+-------+------+------+-------------------+
|           1 | 172.16.10.72:3306 | up    | rw   | NULL |                 0 |
|           2 | 172.16.10.61:3306 | up    | ro   | NULL |                 0 |
+-------------+-------------------+-------+------+------+-------------------+
2 rows in set (0.00 sec)

现在，主从状态全部变成了up状态。