MySQL Proxy最壮大的一项功能是告终“读写离别(Read/Write Splitting)”。它的原理是让主数据库处理事务性查询，而从数据库处理SELECT查询。数据库复制被用来把事务性查询导致的改变同步到集群中的从数据库。
- max_conns = s.connected_clients
- max_conns_ndx = i
- end
- end
- end
至此，我们找到了一个具有安逸连接的从数据库
- if max_conns_ndx > 0 then
- proxy.connection.backend_ndx = max_conns_ndx
- end
- else
发送到主数据库
- end
- return proxy.PROXY_SEND_QUERY
始终想等到BETA版出来再试探的，可还是经不住勾引阿,下午终于有工夫测验一下了。
（本文参看地址：blog.chinaunix.net/u/8111/showart.php?id=451420）
一、必备软件：
1、LUA
能够去LUA的官方下载：dpa.nsysu.edu.tw/Downloads/MySQL-Proxy/。
可能去MYSQL官方下载源代码。
我这里下载了：
mysql.cdpa.nsysu.edu.tw/Downloads/MySQL-Proxy/mysql-proxy-0.6.0.tar.gz
3、测验过程中废止了B和C的REPLICATION。这么SQL语句一下子就看出来从哪里来的。
万一是M-S（能够先在SLAVE上举行STOP SLAVE）
二、测验主机地址：
1、MySQL Proxy 安装地址：192.168.0.234(简称A)
2、MySQL 服务器地址：192.168.0.235(简称B)/236(简称C)
三、安装经验：
万一是按照二进制包安装的，跳过这一步。
1、 LUA的安装
- [root@localhost ~]#tar zxvf lua-5.1.2.tar.gz -C /usr/local
- [root@localhost ~]# cd /usr/local/
- [root@localhost local]# mv lua-5.1 lua
- [root@localhost lua]# cd lua
- [root@localhost lua]#make local;make install;
导出环境变量：
- [root@localhost lua]#export LUA_CFLAGS="-I/usr/local/include" LUA_LIBS="-L/usr/local/lib -llua -ldl" LDFLAGS="-lm"
2、MySQL Proxy 安装
- [root@localhost ~]#tar -zxvf mysql-proxy-0.6.1-linux-rhel4-x86-32bit.tar.gz -C /usr/local/mysql/
- [root@localhost ~]#cd /usr/local/mysql
- [root@localhost mysql]#mv mysql-proxy-0.6.1-linux-rhel4-x86-32bit/ mysql-proxy
- [root@localhost sbin]# export PATH=$PATH:/usr/local/mysql/mysql-proxy/sbin/
四、利用MySQL Proxy
1、察看帮助选项
- [root@localhost ~]# mysql-proxy --help-all
2、对MySQL 垄断
MySQL服务器假想曾经安装。(安装环节这里就不写了)
两台机器上的表初始构造和数据都是一样的，而且都有t_girl_user这个用户。
- mysql> desc t;
- +-------+----------+------+-----+---------+----------------+
- | Field | Type | Null | Key | Default | Extra |
- +-------+----------+------+-----+---------+----------------+
- | id | int(11) | NO | PRI | NULL | auto_increment |
- | c_str | char(64) | NO | | | |
- +-------+----------+------+-----+---------+----------------+
- 2 rows in set (0.00 sec)
- 2 rows in set (0.00 sec)
我在B上插入一条登记
- mysql> insert into t(c_str) values('B');
- Query OK, 1 row affected (0.00 sec)
在C上同样插入一条登记
- mysql> insert into t(c_str) value('C');
- Query OK, 1 row affected (0.00 sec)
- mysql>
3、启用MySQL-Proxy（测验读写离别）
- [root@localhost sbin]# mysql-proxy --proxy-read-only-backend-addresses=192.168.0.236:3306 --proxy-backend-addresses=192.168.0.235:3306
- --proxy-lua-script=/usr/local/mysql/mysql-proxy/share/mysql-proxy/rw-splitting.lua &
- [1] 32554
让MYSQL PROXY积极启用的容易脚本
- #!/bin/sh
- # export PATH=$PATH:/usr/local/mysql-proxy
- cd /usr/local/mysql-proxy
- ./mysql-proxy --proxy-read-only-backend-addresses=192.168.0.236:3306 --proxy-backend-addresses=192.168.0.235:3306 --proxy-lua-script=rw-splitting.lua >> /tmp/log
这个例子中局限192.168.0.236为只读,192.168.0.235为可写。
#p#
4、下来我们来看试探收获。
我们用几台客户端开启4个连接。
- [root@localhost ~]# /usr/local/mysql/bin/mysql -ut_girl_user -p123456 -P4040 -h192.168.0.234 -Dt_girl
我这边曾经启用了好几个客户端，这里就不贴了，号召和上面的一样。
写数据。
- mysql> insert into t(c_str) values ('wangwang');
- Query OK, 1 row affected (0.01 sec)
- mysql> show processlist;
- +----+-------------+---------------------+--------+---------+------+-------+------------------+
- | Id | User | Host | db | Command | Time | State | Info |
- +----+-------------+---------------------+--------+---------+------+-------+------------------+
- | 12 | t_girl_user | 192.168.0.234:44975 | t_girl | Sleep | 28 | | NULL |
- | 13 | t_girl_user | 192.168.0.234:44976 | t_girl | Sleep | 15 | | NULL |
- | 14 | t_girl_user | 192.168.0.234:44977 | t_girl | Sleep | 19 | | NULL |
- | 15 | t_girl_user | 192.168.0.234:44978 | t_girl | Query | 0 | NULL | show processlist |
- +----+-------------+---------------------+--------+---------+------+-------+------------------+
- 4 rows in set (0.00 sec)
- 4 rows in set (0.00 sec)
读数据（目前还是写和读都在B上）
- mysql> select * from t;
- +----+----------+
- | id | c_str |
- +----+----------+
- | 1 | B |
- | 2 | wangwang |
- +----+----------+
- 2 rows in set (0.00 sec)
再添置一个客户端连接。
- 1 row in set (0.00 sec)
- mysql> show processlist;
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- | Id | User | Host | db | Command | Time | State | Info |
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- | 2 | system user | | NULL | Connect | 1842 | Has read all relay log; waiting for the slave I/O thread to update it | NULL |
- | 5 | root | localhost | t_girl | Query | 0 | NULL | show processlist |
- | 12 | t_girl_user | 192.168.0.234:44975 | t_girl | Sleep | 446 | | NULL |
- | 13 | t_girl_user | 192.168.0.234:44976 | t_girl | Sleep | 188 | | NULL |
- | 14 | t_girl_user | 192.168.0.234:44977 | t_girl | Sleep | 206 | | NULL |
- | 15 | t_girl_user | 192.168.0.234:44978 | t_girl | Sleep | 203 | | NULL |
- | 16 | t_girl_user | 192.168.0.234:44979 | t_girl | Sleep | 164 | | NULL |
- | 17 | t_girl_user | 192.168.0.234:44980 | t_girl | Sleep | 210 | | NULL |
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- 8 rows in set (0.00 sec)
目前我们来读数据。
- mysql> select * from t;
- +----+-------+
- | id | c_str |
- +----+-------+
- | 1 | C |
- +----+-------+
- 1 row in set (0.00 sec)
这个数据很显明是来自C的。
再插入一条登记
- mysql> insert into t(c_str) values ('wangwei');
- Query OK, 1 row affected (0.00 sec)
- mysql> select * from t;
- +----+-------+
- | id | c_str |
- +----+-------+
- | 1 | C |
- +----+-------+
- 1 row in set (0.00 sec)
C上的数据未曾变，还是未曾数据。
目前跑到B上看看kaibanla.com。
- mysql> show processlist;
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- | Id | User | Host | db | Command | Time | State | Info |
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- | 2 | system user | | NULL | Connect | 1842 | Has read all relay log; waiting for the slave I/O thread to update it | NULL |
- | 5 | root | localhost | t_girl | Query | 0 | NULL | show processlist |
- | 12 | t_girl_user | 192.168.0.234:44975 | t_girl | Sleep | 446 | | NULL |
- | 13 | t_girl_user | 192.168.0.234:44976 | t_girl | Sleep | 188 | | NULL |
- | 14 | t_girl_user | 192.168.0.234:44977 | t_girl | Sleep | 206 | | NULL |
- | 15 | t_girl_user | 192.168.0.234:44978 | t_girl | Sleep | 203 | | NULL |
- | 16 | t_girl_user | 192.168.0.234:44979 | t_girl | Sleep | 164 | | NULL |
- | 17 | t_girl_user | 192.168.0.234:44980 | t_girl | Sleep | 210 | | NULL |
- +----+-------------+---------------------+--------+---------+------+-----------------------------------------------------------------------+------------------+
- 8 rows in set (0.00 sec)
- mysql> select * from t;
- +----+----------+
- | id | c_str |
- +----+----------+
- | 1 | B |
- | 2 | wangwang |
- | 3 | wangwei |
- +----+----------+
- 3 rows in set (0.00 sec)
数据已成功插入到B中。
关于使用MySQL Proxy告终读写离别的知识就介绍到这里，希望能对您有所帮助。
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