mysql读写分离Amoeba3.x的实现
1）安装amoeba（http://sourceforge.net/projects/amoeba/files/）
下载amoeba（1.2.0-GA）后解压到本地（/usr/local/amoeba），即完成安装
2）配置amoeba
# ls
access_list.conf amoeba.xml dbServers.xml functionMap.xml log4j.xml ruleFunctionMap.xml
amoeba.dtd dbserver.dtd function.dtd log4j.dtd rule.dtd rule.xml
在这里我主要介绍配置 amoeba.xml、dbServers.xml、log4j.xml 三个主要的配置文件，其它文件没有特殊需要默认就可以了夺
# vi access_list.conf 修改允许访问列表
2.0）192.168.152.*:yes
# vi amoeba.xml 修改主配置文件
2.1）把默认端口8066改成3306；前提是你的数据库与amoeba安装的机器不在同一个机器上
<property name="port">3066</property>
2.2）把默认连接用户名和密码改成自己的
<property name="user">root</property>
<property name="password">123456</property>
2.3）把默认的代理服务器客户端进程线程大小数改成300
<!-- proxy server client process thread size -->
<property name="executeThreadSize">300</property>
2.4）把默认注释掉的读写分离选项，把注释去掉并readpool修改成server2
<property name="writePool">server1</property>
<property name="readPool">server2</property>
vi dbServers.xml
增加SEVER2模块，里面的连接用户名密码及地址都表示两台MYSQL的物理机器，192.168.1.11和192.168.1.13 另SERVER1是写，SERVER是读
需要手动增加SERVER2代码,最终改变成如下：
<?xml version="1.0" encoding="gbk"?>
<!DOCTYPE amoeba:dbServers SYSTEM "dbserver.dtd">
<amoeba:dbServers xmlns:amoeba="http://amoeba.meidusa.com/">
<!--
Each dbServer needs to be configured into a Pool,
If you need to configure multiple dbServer with load balancing that can be simplified by the following configuration:
add attribute with name virtual = "true" in dbServer, but the configuration does not allow the element with name factoryConfig
such as 'multiPool' dbServer
-->
<dbServer name="abstractServer" abstractive="true">
<factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory">
<property name="manager">${defaultManager}</property>
<property name="sendBufferSize">64</property>
<property name="receiveBufferSize">128</property>
<!-- mysql port -->
<property name="port">3306</property>
<!-- mysql schema -->
<property name="schema">test</property>
<!-- mysql user -->
<property name="user">root</property>
<!-- mysql password -->
<property name="password">123456</property>
</factoryConfig>
<poolConfig class="com.meidusa.amoeba.net.poolable.PoolableObjectPool">
<property name="maxActive">500</property>
<property name="maxIdle">500</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="server1" parent="abstractServer">
<factoryConfig>
<!-- mysql ip -->
<property name="ipAddress">192.168.2.11</property>
</factoryConfig>
</dbServer>
<dbServer name="server2" parent="abstractServer">
<factoryConfig>
<!-- mysql ip -->
<property name="ipAddress">192.168.2.13</property>
</factoryConfig>
</dbServer>
<dbServer name="multiPool" virtual="true">
<poolConfig class="com.meidusa.amoeba.server.MultipleServerPool">
<!-- Load balancing strategy: 1=ROUNDROBIN , 2=WEIGHTBASED , 3=HA-->
<property name="loadbalance">1</property>
<!-- Separated by commas,such as: server1,server2,server1 -->
<property name="poolNames">server1</property>
</poolConfig>
</dbServer>
</amoeba:dbServers>
6：修改log4j.xml 取消日志文件生成（太大了，磁盘很容易满；）
暂时还不清楚如何进行修改
7：性能优化，打开bin/amoeba（window下可用）
DEFAULT_OPTS="-server -Xms256m -Xmx256m -Xss128k"
改成
DEFAULT_OPTS="-server -Xms512m -Xmx512m -Xmn100m -Xss1204k"
8.设置压力比
大家可能会想到，我们加入只有两台数据库服务器，一台主，一台从，按照上面的配置只能是主和从的读取比率是1:1,而写又全部在主上进行，这样主的压力就很大了，所以如果能让主和从的读设置权重，比如设置成1:3,这样就可以很好的解决主从不压力均衡的问题！通过研究确实可以！
配置就是将上面的读的池的配置更改一下：
将<property name="poolNames">server1,server2</property>更改成
<property name="poolNames">server1,server2,server2,server2</property>
9：启动amoeba(1.2的nohup /usr/local/amoeba/bin/amoeba start 2>&1 >/dev/null &)
/usr/local/amoeba/bin/launcher
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.
10.设置mysql主从服务器的允许访问的用户和地址
三.client端调用与测试
1）在装有mysql客户端的机器上使用:
mysql -uroot -p123456 -P3306 -h192.168.152.146
参数分别是amoeba的用户名、密码、端口号和所做主机的地址
2）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
通过以上验证得知简单的master-slave搭建和实战得以生效
==========================注意事项=================================================================
Amoeba不支持事务
Amoeba不支持跨库join和排序
Insert语句必须指定表的列名
Amoeba不支持分库分表。
Amoeba不支持分库分表，只能分MySQL实例。
Amoeba不支持大数据量的查询。
Amoeba需要更严格的SQL语句规范
