mysql-poxy 实现mysql主从架构读写分离

        在高并发系统设计中，后端数据库的性能往往会成为系统的瓶颈，这时候就需要进行合理的设计，以分摊后端数据库的压力，比如在数据层前面构建缓存层、数据文件存放在RAID这样的设备、对数据进行分库分表分区存放、合理利用索引、进行数据的读写分离等。mysql-proxy提供了mysql数据库的读写分离能力，mysql-proxy通过Lua脚本能分析得出用户的sql请求，如果发现在是read请求，则会转化到master-slave模型的slave中，如果是write请求，则会转发到master中，以达到读写分离的目的，在一定程度上能大大增加系统的性能。下面来一步步通过mysql-proxy搭建mysql的读写分离。

一、环境准备

    os：centos6.4

    mysql-slave：version：5.6.13    ip：192.168.1.111

    mysql-master：version：5.6.13    ip：192.168.1.110

    mysql-proxy：version：0.85    ip：192.168.1.112

二、环境搭建

    1、mysql主从复制搭建

        mysql安装具体参考：http://crazytechnology.blog.51cto.com/6906973/1640197

        tips：mysql从5.6起，主从复制中采用了GTID，GTID为每个数据库事务编码一个number，并为

        每个server赋予一个global uuid，通过uuid和事务编号来进行数据的复制和恢复，这种方案更有利

        于在高可用的环境中数据的恢复。在5.6后，mysql主从架构中还支持多线程复制，即可以启动多个

        sql thread对relay log进行处理，默认的线程数建议为要同步的数据库的个数。

        由于是搭建5.6.13的mysql主从架构，因上安装好mysql后。在/etc/my.cnf中主要配置如下：

        master:

        [mysqld]

        port = 3306

        datadir = /data/mysql

        server_id = 1

        socket = /tmp/mysql.sock

        innodb_file_per_table = 1

        log-bin = master-bin

        binlog-format=ROW

        log-slave-updates=true

        gtid-mode=on

        enforce-gtid-consistency=true

        master-info-repository=TABLE

        relay-log-info-repository=TABLE

        sync-master-info=1

        slave-parallel-workers=2

        binlog-checksum=CRC32

        master-verify-checksum=1

        slave-sql-verify-checksum=1

        binlog-rows-query-log_events=1

        report-port=3306

        report-host=master.lee.com

            

            vim /etc/hosts添加一条条目

            192.168.1.110 master.lee.com master

        slave：

        [mysqld]

        datadir = /data/mysql    #存放数据目录

        port = 3306    #启动端口

        server_id = 100    #server_id

        socket = /tmp/mysql.sock

        innodb_file_per_table = 1    #每表一个表空间

        binlog-format=ROW    

        log-slave-updates=true

        gtid-mode=on     #启动gtid

        enforce-gtid-consistency=true

        master-info-repository=TABLE    #master记录bin-log的位置（myql.slave_master_info）

        relay-log-info-repository=TABLE    #slave记录relay-log的地方，默认为file

        sync-master-info=1    #启用后可确保无信息丢失

        slave-parallel-workers=2    #启动的sql thread线程数

        binlog-checksum=CRC32    #二进制校验算法crc32

        master-verify-checksum=1    #启用复制有关的校验功能

        slave-sql-verify-checksum=1    #启用复制有关的校验功能

        binlog-rows-query-log_events=1    #记录相关事件信息，降低排错复杂度

        report-port=3306    #通知给master的端口号

        log-bin=mysql-bin.log    #开启二进制日志功能，可以拥有自己的从服务器

        report-host=slave.lee.com    #通知给master的主机名

        

        在master中创建主从复制用户

        mysql> grant replication slave on *.* to 'repluser'@'192.168.1.%' identified by 'replpass';

        在slave中连接master:

        mysql> change master to master_host='192.168.1.110',master_user='repluser',master_password

        ='replpass',master_auto_position=1;

        启动myql slave

        mysql> start slave

        

    2、安装mysql-proxy

        tar xf mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit.tar.gz -C /usr/local

        cd /usr/local

        ln -sv mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit/ mysql-proxy

        创建mysql-proxy用户

        useradd -r -s /sbin/nologin mysql-proxy

   

     

      为mysql-proxy提供SysV脚本，将下面代码复制到/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/init.d/mysql-proxy

        chkconfig --add mysql-proxy

        chkconfig mysql-proxy on

        为mysql-prox提供服务脚本

        vim /etc/sysconfig/mysql-proxy

        

       DMIN_USER="admin"    #管理员用户名

        ADMIN_PASSWORD="admin"    #管理员用户密码

        ADMIN_ADDRESS="192.168.1.112:4041"    #管理mysql-proxy监听的套接字

           #admin lua脚本

        ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"

        PROXY_ADDRESS="192.168.1.112:3306"    #mysql-proxy监听的套接字

        PROXY_USER="mysql-proxy"    #启动mysql-proxy服务的用户

          #mysql-proxy启动的选项

        PROXY_OPTIONS="--daemon --log-level=debug --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.1.110:3306 --proxy-read-only-backend-addresses=192.168.1.111:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua

        

        #--daemon：以守护进程方式启动

        #--log-level=debug，日志级别,此处为了调试而用

        #--log-use-syslog ： 通过系统的syslog记录日志

        #--plugins：插件

        #--proxy-backend-addresses：后台读写数据库服务器(rw)，可添加多个

        #--proxy-read-only-backend-addresses：后台只读数据库服务器(ro)，可添加多个

        #--proxy-lua-script：mysql读写分离lua脚本

        复制下面代码，到/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua文件中

        

    --[[ $%BEGINLICENSE%$

     Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.

    

     This program is free software; you can redistribute it and/or

     modify it under the terms of the GNU General Public License as

     published by the Free Software Foundation; version 2 of the

     License.

    

     This program is distributed in the hope that it will be useful,

     but WITHOUT ANY WARRANTY; without even the implied warranty of

     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

     GNU General Public License for more details.

    

     You should have received a copy of the GNU General Public License

     along with this program; if not, write to the Free Software

     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA

     02110-1301  USA

    

     $%ENDLICENSE%$ --]]

    

    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

    
     启动mysql-proxy

        service mysql-proxy start

        查看是否启动成功

        netstat -tlnp可查看到mysql-proxy监听在3306和4041（管理）端口上。

    3、读写分离测试

        在master中创建一个测试管理用户mproxyadmin

        mysql> grant all on *.* to 'mproxyadmin'@'192.168.1.112' identified by 'mproxypass';

        mysql> flush priviledges;

        选择从slave中登录mysql-proxy

        mysql -umproxyadmin -h192.168.1.112 -p;

        登录进去

        创建一个aa数据库

        mysql> create database aa;

        可以看到主从数据库都有已经创建了aa数据库。

        

        在slave中登录mysql-proxy所的admin管理后台

        mysql -uadmin -padmin -h192.168.1.112 --port=4041

        管理后台只有一条sql语句有用，查看backends的状态信息：

        mysql> select * from backends;

        

        可看到此时的backends有两个，但状态为unknown.，且master为读写模式，slave为主从模式

        当在主中进行相关非查询操作时，master的state会变成up。当进行查询时，slave的状态也会变

        成up,当二者都激活后，mysql-proxy就能进行读写分离了。

        

        由于mysql-proxy启动时日志级别设计为debug,所以在mysql-proxy所在机子可以轻易地看到日志

        信息，首先在slave上连接上mysq_proxy，在刚才创建的aa数据库中创建一张test表，

        

        这时在mysql-proxy中看到的日志是：

        

        由is_slave为false可知道，这个创表语句是在master中执行的。

        下面我们为这个表插入一条数据，然后再select出来

        mysql> insert into test values(1,"test");

        mysql> select * from test;

        

    这时发现select语句，is_slave为true,也就是查询是在slave中执行的。

    以后每执行查询操作都会在slave中执行，其它的操作都会在master中执行，这就实现了mysql的读写

    分离。