Mysql 实战之——读写分离方案

Linux环境：Centos 6.8  64-bit

Mysql 版本：5.1.7

 

一、准备工作：部署Mysql主从复制

二、使用Amoeba数据库代理来实现读写分离

Amoeba作为数据库代理，以中间件的形式存在，拓扑图如下所示：（Amoeba官网的一张图）

1、下载Amoeba：https://sourceforge.net/projects/amoeba/files/

2、解压并复制到local目录

[root@ linux ~]# unzip amoeba-mysql-3.0.5-RC-distribution.zip[root@ linux ~]# cp -rf amoeba-mysql-3.0.5-RC /usr/local

3、启动Amoeba。

[root@chenllcentos ~]# /usr/local/amoeba-mysql-3.0.5-RC/bin/launcher

如果出现fatal exception：

The stack size specified is too small, Specify at least 228kError: Could not create the Java Virtual Machine.Error: A fatal exception has occurred. Program will exit.

原因是由于stack size太小，导致JVM启动失败，要如何修改呢？

 解决：

[root@ linux ~]# vi /usr/local/amoeba-mysql-3.0.5-RC/jvm.properties

将内容：

JVM_OPTIONS="-server -Xms256m -Xmx1024m -Xss196k -XX:PermSize=16m -XX:MaxPermSize=96m"

替换为：

JVM_OPTIONS="-server -Xms1024m -Xmx1024m -Xss256k -XX:PermSize=16m -XX:MaxPermSize=96m"

4、修改配置文件：Amoeba完成读写分离的实现主要是依靠2个非常重要的配置文件：

dbServers.xml  和  amoeba.xml

4.1、首先，看看dbServers.xml文件

[root@localhost conf]# cat dbServer.xml

这个文件主要是配置数据库链接，主库，还有从库（slave）节点的信息，以及数据库连接池信息

如下内容就是这个文件的配置

<?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   --><!-- 该dbServer节点abstractive="true"，包含Mysql的公共配置信息，其他dbServer节点都继承该节点 --><!-- 设置节点配置的继承结构，可以避免重复配置相同信息，减少配置文件冗余 --><dbServer name="abstractServer" abstractive="true">    <factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory">        <property name="connectionManager">${defaultManager}</property>        <property name="sendBufferSize">64</property>        <property name="receiveBufferSize">128</property>        <!-- mysql port -->        <!-- Mysql默认端口 -->        <property name="port">3306</property>        <!-- mysql schema -->        <!-- 默认连接的数据库，若不存在需要事先创建，否则Amoeba启动报错 -->        <property name="schema">testdb</property>        <!-- mysql user -->        <property name="user">root</property>        <property name="password">222</property>    </factoryConfig>    <poolConfig class="com.meidusa.toolkit.common.poolable.PoolableObjectPool">        <property name="maxActive">500</property>        <property name="maxIdle">500</property>        <property name="minIdle">1</property>        <property name="minEvictableIdleTimeMillis">600000</property>        <property name="timeBetweenEvictionRunsMillis">600000</property>        <property name="testOnBorrow">true</property>        <property name="testOnReturn">true</property>        <property name="testWhileIdle">true</property>    </poolConfig></dbServer><!-- Mysql主服务器master节点继承abstractServer --><dbServer name="master"  parent="abstractServer">    <factoryConfig>        <!-- master数据库主机地址 -->        <property name="ipAddress">192.168.48.133</property>    </factoryConfig></dbServer><!-- Mysql从服务器slave节点继承abstractServer --><dbServer name="slave1"  parent="abstractServer">    <factoryConfig>        <!-- slave数据库主机地址 -->        <property name="ipAddress">192.168.48.132</property>    </factoryConfig></dbServer><!-- 如果有多个从服务器节点, 可以复制多个dbServer --><!-- 配置数据库读取连接池 Amoeba实现读写分离根据readPool 连接池来实现--><dbServer name="readPool" 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">slave1</property>    </poolConfig></dbServer>

配置完成之后：

4.2、接着配置amoeba.xml

vi amoeba.xml

内容如下：

<?xml version="1.0" encoding="gbk"?><!DOCTYPE amoeba:configuration SYSTEM "amoeba.dtd"><amoeba:configuration xmlns:amoeba="http://amoeba.meidusa.com/"><proxy><!-- service class must implements com.meidusa.amoeba.service.Service --><service name="Amoeba for Mysql" class="com.meidusa.amoeba.mysql.server.MySQLService"><!-- port --><property name="port">8066</property><!-- bind ipAddress --><!-- <property name="ipAddress">127.0.0.1</property> --><property name="connectionFactory"><bean class="com.meidusa.amoeba.mysql.net.MysqlClientConnectionFactory"><property name="sendBufferSize">128</property><property name="receiveBufferSize">64</property></bean></property><property name="authenticateProvider"><bean class="com.meidusa.amoeba.mysql.server.MysqlClientAuthenticator"><property name="user">root</property><property name="password"></property><property name="filter"><bean class="com.meidusa.toolkit.net.authenticate.server.IPAccessController"><property name="ipFile">${amoeba.home}/conf/access_list.conf</property></bean></property></bean></property></service><runtime class="com.meidusa.amoeba.mysql.context.MysqlRuntimeContext"><!-- proxy server client process thread size --><property name="executeThreadSize">128</property><!-- per connection cache prepared statement size  --><property name="statementCacheSize">500</property><!-- default charset --><property name="serverCharset">utf8</property><!-- query timeout( default: 60 second , TimeUnit:second) --><property name="queryTimeout">60</property></runtime></proxy><!-- Each ConnectionManager will start as threadmanager responsible for the Connection IO read , Death Detection--><connectionManagerList><connectionManager name="defaultManager" class="com.meidusa.toolkit.net.MultiConnectionManagerWrapper"><property name="subManagerClassName">com.meidusa.toolkit.net.AuthingableConnectionManager</property></connectionManager></connectionManagerList><!-- default using file loader --><dbServerLoader class="com.meidusa.amoeba.context.DBServerConfigFileLoader"><property name="configFile">${amoeba.home}/conf/dbServers.xml</property></dbServerLoader><queryRouter class="com.meidusa.amoeba.mysql.parser.MysqlQueryRouter"><property name="ruleLoader"><bean class="com.meidusa.amoeba.route.TableRuleFileLoader"><property name="ruleFile">${amoeba.home}/conf/rule.xml</property><property name="functionFile">${amoeba.home}/conf/ruleFunctionMap.xml</property></bean></property><property name="sqlFunctionFile">${amoeba.home}/conf/functionMap.xml</property><property name="LRUMapSize">1500</property><property name="defaultPool">multiPool</property><!--<property name="writePool">server1</property><property name="readPool">server1</property>--><property name="needParse">true</property></queryRouter></amoeba:configuration>

我们需要改的有3个地方：

5、启动

cd /usr/local/amoeba-mysql-3.0.5-RC/bin/./launcher

出现如下信息就是启动成功了

2016-10-11 23:20:55 [INFO] Project Name=Amoeba-MySQL, PID=4097 , System shutdown ....2016-10-11 23:27:49 [INFO] Project Name=Amoeba-MySQL, PID=4162 , starting...log4j:WARN log4j config load completed from file:/usr/local/amoeba-mysql-3.0.5-RC/conf/log4j.xml2016-10-11 23:27:50,736 INFO  context.MysqlRuntimeContext - Amoeba for Mysql current versoin=5.1.45-mysql-amoeba-proxy-3.0.4-BETAlog4j:WARN ip access config load completed from file:/usr/local/amoeba-mysql-3.0.5-RC/conf/access_list.conf2016-10-11 23:27:51,863 INFO  net.ServerableConnectionManager - Server listening on 0.0.0.0/0.0.0.0:8066.

6、测试

先停止从库的主从复制

mysql>slave stop;

 查询主库的数据

mysql> select * from t_test;+------+------+| id   | name |+------+------+|    3 | t3   |+------+------+

查询从库的数据

mysql> select * from t_test;+------+------+| id   | name |+------+------+|    1 | aaa  |+------+------+

 登录Amoeba

mysql -uroot -p111111 -h192.168.48.133 -P8066

先使用查询语句

-- 经过多次测试查询，始终返回从库的数据mysql> select * from t_test ;+------+------+| id   | name |+------+------+|    1 | aaa  |+------+------+1 row in set (0.00 sec)

再使用insert语句

mysql> insert into t_test (id,name) values (100,'100');Query OK, 1 row affected (0.02 sec)mysql> insert into t_test (id,name) values (200,'200');Query OK, 1 row affected (0.00 sec)

现在看看insert语句的结果：

-- 查询从库的结果：mysql> select * from t_test;+------+------+| id   | name |+------+------+|  100 | 100  ||  200 | 200  |+------+------+

-- 查询主库的结果mysql> select * from t_test;+------+------+| id   | name |+------+------+|  200 | 200  ||  100 | 100  |+------+------+2 rows in set (0.00 sec)

--在Amoeba执行查询的结果：mysql> select * from t_test ;+------+------+| id   | name |+------+------+|  100 | 100  ||  200 | 200  |+------+------+2 rows in set (0.07 sec)

已经成功了。。。查询操作，始终查询的是从库的数据，而insert操作，始终是对主库进行操作

JAVA程序中整合amoeba的话，只需要把数据库链接改成amoeba的就行了。。

在企业的实际项目中，这样做的好处是，不需要对代码进行硬编码，具备非常高的解耦作用，而且，Amoeba的配置也非常的简单，其实还有分库和分表的操作，这里就不做演示

三、报错信息

amoeba里查询的时候报错：amoeba ERROR 1044 (42000): Could not create a validated object, cause: ValidateObject failed

这个问题，我在网上找到了一个原因，就是，amoeba去从库查询的时候，账号没权限。grant 赋予从库那个账号所有权限就好了。