一个完整的mysql读写分离环境包括以下几个部分：
应用程序client
database proxy
database集群
在本次实战中，应用程序client基于c3p0连接后端的database proxy。database proxy负责管理client实际访问database的路由策略，采用开源框架amoeba。database集群采用mysql的master-slave的replication方案。整个环境的结构图如下所示：
实战步骤与详解
一.搭建mysql的master-slave环境
1）分别在host1（10.20.147.110）和host2（10.20.147.111）上安装mysql（5.0.45），具体安装方法可见官方文档
2）配置master
首先编辑/etc/my.cnf，添加以下配置：
log-bin=mysql-bin #slave会基于此log-bin来做replication
server-id=1 #master的标示
binlog-do-db = amoeba_study #用于master-slave的具体数据库
然后添加专门用于replication的用户：
mysql> GRANT REPLICATION SLAVE ON *.* TO repl@10.20.147.111 IDENTIFIED BY '111111';
重启mysql，使得配置生效：
/etc/init.d/mysqld restart
最后查看master状态：
3）配置slave
首先编辑/etc/my.cnf，添加以下配置：
server-id=2 #slave的标示
配置生效后，配置与master的连接：
mysql> CHANGE MASTER TO
-> MASTER_HOST='10.20.147.110',
-> MASTER_USER='repl',
-> MASTER_PASSWORD='111111',
-> MASTER_LOG_FILE='mysql-bin.000003',
-> MASTER_LOG_POS=161261;
其中MASTER_HOST是master机的ip，MASTER_USER和MASTER_PASSWORD就是我们刚才在master上添加的用户，MASTER_LOG_FILE和MASTER_LOG_POS对应与master status里的信息
最后启动slave：
mysql> start slave;
4）验证master-slave搭建生效
通过查看slave机的log（/var/log/mysqld.log）：
100703 10:51:42 [Note] Slave I/O thread: connected to master 'repl@10.20.147.110:3306', replication started in log 'mysql-bin.000003' at position 161261
如看到以上信息则证明搭建成功，如果有问题也可通过此log找原因
二.搭建database proxy
此次实战中database proxy采用amoeba ，它的相关信息可以查阅官方文档，不在此详述
1）安装amoeba
下载amoeba（1.2.0-GA）后解压到本地（D:/openSource/amoeba-mysql-1.2.0-GA），即完成安装
2）配置amoeba
先配置proxy连接和与各后端mysql服务器连接信息（D:/openSource/amoeba-mysql-1.2.0-GA/conf/amoeba.xml）：
<server>
<!-- proxy server绑定的端口 -->
<property name="port">8066</property>
<!-- proxy server绑定的IP -->
<!--
<property name="ipAddress">127.0.0.1</property>
-->
<!-- proxy server net IO Read thread size -->
<property name="readThreadPoolSize">20</property>
<!-- proxy server client process thread size -->
<property name="clientSideThreadPoolSize">30</property>
<!-- mysql server data packet process thread size -->
<property name="serverSideThreadPoolSize">30</property>
<!-- socket Send and receive BufferSize(unit:K) -->
<property name="netBufferSize">128</property>
<!-- Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm). -->
<property name="tcpNoDelay">true</property>
<!-- 对外验证的用户名 -->
<property name="user">root</property>
<!-- 对外验证的密码 -->
<property name="password">root</property>
</server>
<server> <!-- proxy server绑定的端口 --> <property name="port">8066</property> <!-- proxy server绑定的IP --> <!-- <property name="ipAddress">127.0.0.1</property> --> <!-- proxy server net IO Read thread size --> <property name="readThreadPoolSize">20</property> <!-- proxy server client process thread size --> <property name="clientSideThreadPoolSize">30</property> <!-- mysql server data packet process thread size --> <property name="serverSideThreadPoolSize">30</property> <!-- socket Send and receive BufferSize(unit:K) --> <property name="netBufferSize">128</property> <!-- Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm). --> <property name="tcpNoDelay">true</property> <!-- 对外验证的用户名 --> <property name="user">root</property> <!-- 对外验证的密码 --> <property name="password">root</property> </server>
以上是proxy提供给client的连接配置
<dbServerList>
<dbServer name="server1">
<!-- PoolableObjectFactory实现类 -->
<factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory">
<property name="manager">defaultManager</property>
<!-- 真实mysql数据库端口 -->
<property name="port">3306</property>
<!-- 真实mysql数据库IP -->
<property name="ipAddress">10.20.147.110</property>
<property name="schema">amoeba_study</property>
<!-- 用于登陆mysql的用户名 -->
<property name="user">root</property>
<!-- 用于登陆mysql的密码 -->
<property name="password"></property>
</factoryConfig>
<!-- ObjectPool实现类 -->
<poolConfig class="com.meidusa.amoeba.net.poolable.PoolableObjectPool">
<property name="maxActive">200</property>
<property name="maxIdle">200</property>
<property name="minIdle">10</property>
<property name="minEvictableIdleTimeMillis">600000</property>
<property name="timeBetweenEvictionRunsMillis">600000</property>
<property name="testOnBorrow">true</property>
<property name="testWhileIdle">true</property>
</poolConfig>
</dbServer>
<dbServer name="server2">
<!-- PoolableObjectFactory实现类 -->
<factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory">
<property name="manager">defaultManager</property>
<!-- 真实mysql数据库端口 -->
<property name="port">3306</property>
<!-- 真实mysql数据库IP -->
<property name="ipAddress">10.20.147.111</property>
<property name="schema">amoeba_study</property>
<!-- 用于登陆mysql的用户名 -->
<property name="user">root</property>
<!-- 用于登陆mysql的密码 -->
<property name="password"></property>
</factoryConfig>
<!-- ObjectPool实现类 -->
<poolConfig class="com.meidusa.amoeba.net.poolable.PoolableObjectPool">
<property name="maxActive">200</property>
<property name="maxIdle">200</property>
<property name="minIdle">10</property>
<property name="minEvictableIdleTimeMillis">600000</property>
<property name="timeBetweenEvictionRunsMillis">600000</property>
<property name="testOnBorrow">true</property>
<property name="testWhileIdle">true</property>
</poolConfig>
</dbServer>
</dbServerList>
<dbServerList> <dbServer name="server1"> <!-- PoolableObjectFactory实现类 --> <factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory"> <property name="manager">defaultManager</property> <!-- 真实mysql数据库端口 --> <property name="port">3306</property> <!-- 真实mysql数据库IP --> <property name="ipAddress">10.20.147.110</property> <property name="schema">amoeba_study</property> <!-- 用于登陆mysql的用户名 --> <property name="user">root</property> <!-- 用于登陆mysql的密码 --> <property name="password"></property> </factoryConfig> <!-- ObjectPool实现类 --> <poolConfig class="com.meidusa.amoeba.net.poolable.PoolableObjectPool"> <property name="maxActive">200</property> <property name="maxIdle">200</property> <property name="minIdle">10</property> <property name="minEvictableIdleTimeMillis">600000</property> <property name="timeBetweenEvictionRunsMillis">600000</property> <property name="testOnBorrow">true</property> <property name="testWhileIdle">true</property> </poolConfig> </dbServer> <dbServer name="server2"> <!-- PoolableObjectFactory实现类 --> <factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory"> <property name="manager">defaultManager</property> <!-- 真实mysql数据库端口 --> <property name="port">3306</property> <!-- 真实mysql数据库IP --> <property name="ipAddress">10.20.147.111</property> <property name="schema">amoeba_study</property> <!-- 用于登陆mysql的用户名 --> <property name="user">root</property> <!-- 用于登陆mysql的密码 --> <property name="password"></property> </factoryConfig> <!-- ObjectPool实现类 --> <poolConfig class="com.meidusa.amoeba.net.poolable.PoolableObjectPool"> <property name="maxActive">200</property> <property name="maxIdle">200</property> <property name="minIdle">10</property> <property name="minEvictableIdleTimeMillis">600000</property> <property name="timeBetweenEvictionRunsMillis">600000</property> <property name="testOnBorrow">true</property> <property name="testWhileIdle">true</property> </poolConfig> </dbServer> </dbServerList>
以上是proxy与后端各mysql数据库服务器配置信息，具体配置见注释很明白了
最后配置读写分离策略：
<queryRouter class="com.meidusa.amoeba.mysql.parser.MysqlQueryRouter">
<property name="LRUMapSize">1500</property>
<property name="defaultPool">server1</property>
<property name="writePool">server1</property>
<property name="readPool">server2</property>
<property name="needParse">true</property>
</queryRouter>
<queryRouter class="com.meidusa.amoeba.mysql.parser.MysqlQueryRouter"> <property name="LRUMapSize">1500</property> <property name="defaultPool">server1</property> <property name="writePool">server1</property> <property name="readPool">server2</property> <property name="needParse">true</property> </queryRouter>
从以上配置不然发现，写操作路由到server1（master），读操作路由到server2（slave）
3）启动amoeba
在命令行里运行D:/openSource/amoeba-mysql-1.2.0-GA/amoeba.bat即可：
log4j:WARN log4j config load completed from file:D:/openSource/amoeba-mysql-1.2.0-GA/conf/log4j.xml
log4j:WARN ip access config load completed from file:D:/openSource/amoeba-mysql-1.2.0-GA/conf/access_list.conf
2010-07-03 09:55:33,821 INFO net.ServerableConnectionManager - Server listening on 0.0.0.0/0.0.0.0:8066.
三.client端调用与测试
1）编写client调用程序
具体程序细节就不详述了，只是一个最普通的基于mysql driver的jdbc的数据库操作程序
2）配置数据库连接
本client基于c3p0，具体数据源配置如下：
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
<property name="driverClass" value="com.mysql.jdbc.Driver" />
<property name="jdbcUrl" value="jdbc:mysql://localhost:8066/amoeba_study" />
<property name="user" value="root" />
<property name="password" value="root" />
<property name="minPoolSize" value="1" />
<property name="maxPoolSize" value="1" />
<property name="maxIdleTime" value="1800" />
<property name="acquireIncrement" value="1" />
<property name="maxStatements" value="0" />
<property name="initialPoolSize" value="1" />
<property name="idleConnectionTestPeriod" value="1800" />
<property name="acquireRetryAttempts" value="6" />
<property name="acquireRetryDelay" value="1000" />
<property name="breakAfterAcquireFailure" value="false" />
<property name="testConnectionOnCheckout" value="true" />
<property name="testConnectionOnCheckin" value="false" />
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close"> <property name="driverClass" value="com.mysql.jdbc.Driver" /> <property name="jdbcUrl" value="jdbc:mysql://localhost:8066/amoeba_study" /> <property name="user" value="root" /> <property name="password" value="root" /> <property name="minPoolSize" value="1" /> <property name="maxPoolSize" value="1" /> <property name="maxIdleTime" value="1800" /> <property name="acquireIncrement" value="1" /> <property name="maxStatements" value="0" /> <property name="initialPoolSize" value="1" /> <property name="idleConnectionTestPeriod" value="1800" /> <property name="acquireRetryAttempts" value="6" /> <property name="acquireRetryDelay" value="1000" /> <property name="breakAfterAcquireFailure" value="false" /> <property name="testConnectionOnCheckout" value="true" /> <property name="testConnectionOnCheckin" value="false" /> </bean>
值得注意是，client端只需连到proxy，与实际的数据库没有任何关系，因此jdbcUrl、user、password配置都对应于amoeba暴露出来的配置信息
3）调用与测试
首先插入一条数据：insert into zone_by_id(id,name) values(20003,'name_20003')
通过查看master机上的日志/var/lib/mysql/mysql_log.log：
100703 11:58:42 1 Query set names latin1
1 Query SET NAMES latin1
1 Query SET character_set_results = NULL
1 Query SHOW VARIABLES
1 Query SHOW COLLATION
1 Query SET autocommit=1
1 Query SET sql_mode='STRICT_TRANS_TABLES'
1 Query SHOW VARIABLES LIKE 'tx_isolation'
1 Query SHOW FULL TABLES FROM `amoeba_study` LIKE 'PROBABLYNOT'
1 Prepare [1] insert into zone_by_id(id,name) values(?,?)
1 Prepare [2] insert into zone_by_id(id,name) values(?,?)
1 Execute [2] insert into zone_by_id(id,name) values(20003,'name_20003')
得知写操作发生在master机上
通过查看slave机上的日志/var/lib/mysql/mysql_log.log：
100703 11:58:42 2 Query insert into zone_by_id(id,name) values(20003,'name_20003')
得知slave同步执行了这条语句
然后查一条数据：select t.name from zone_by_id t where t.id = 20003
通过查看slave机上的日志/var/lib/mysql/mysql_log.log：
100703 12:02:00 33 Query set names latin1
33 Prepare [1] select t.name from zone_by_id t where t.id = ?
33 Prepare [2] select t.name from zone_by_id t where t.id = ?
33 Execute [2] select t.name from zone_by_id t where t.id = 20003
得知读操作发生在slave机上
并且通过查看slave机上的日志/var/lib/mysql/mysql_log.log发现这条语句没在master上执行