Mycat读写分离与注意事项

最简单的配置方式，一个主Mysql服务器，一个从Mysql服务器，主从关系先配置好。写都写到主服务器，读可以读主或者从服务器。

一、mycat配置

server。xml：

<?xml version="1.0" encoding="UTF-8"?>
<!-- - - Licensed under the Apache License, Version 2.0 (the "License");
    - you may not use this file except in compliance with the License. - You
    may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0
    - - Unless required by applicable law or agreed to in writing, software -
    distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT
    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the
    License for the specific language governing permissions and - limitations
    under the License. -->
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
    <system>
    <property name="useSqlStat">0</property>  <!-- 1为开启实时统计、0为关闭 -->
    <property name="useGlobleTableCheck">0</property>  <!-- 1为开启全加班一致性检测、0为关闭 -->

        <property name="sequnceHandlerType">2</property>
      <!--  <property name="useCompression">1</property>--> <!--1为开启mysql压缩协议-->
        <!--  <property name="fakeMySQLVersion">5.6.20</property>--> <!--设置模拟的MySQL版本号-->
    <!-- <property name="processorBufferChunk">40960</property> -->
    <!--
    <property name="processors">1</property>
    <property name="processorExecutor">32</property>
     -->
        <!--默认为type 0: DirectByteBufferPool | type 1 ByteBufferArena-->
        <property name="processorBufferPoolType">0</property>
        <!--默认是65535 64K 用于sql解析时最大文本长度 -->
        <!--<property name="maxStringLiteralLength">65535</property>-->
        <!--<property name="sequnceHandlerType">0</property>-->
        <!--<property name="backSocketNoDelay">1</property>-->
        <!--<property name="frontSocketNoDelay">1</property>-->
        <!--<property name="processorExecutor">16</property>-->
        <!--
            <property name="serverPort">8066</property> <property name="managerPort">9066</property>
            <property name="idleTimeout">300000</property> <property name="bindIp">0.0.0.0</property>
            <property name="frontWriteQueueSize">4096</property> <property name="processors">32</property> -->
        <!--分布式事务开关，0为不过滤分布式事务，1为过滤分布式事务（如果分布式事务内只涉及全局表，则不过滤），2为不过滤分布式事务,但是记录分布式事务日志-->
        <property name="handleDistributedTransactions">0</property>
       
            <!--
            off heap for merge/order/group/limit      1开启   0关闭
        -->
        <property name="useOffHeapForMerge">1</property>

        <!--
            单位为m
        -->
        <property name="memoryPageSize">1m</property>

        <!--
            单位为k
        -->
        <property name="spillsFileBufferSize">1k</property>

        <property name="useStreamOutput">0</property>

        <!--
            单位为m
        -->
        <property name="systemReserveMemorySize">384m</property>

        <!--是否采用zookeeper协调切换  -->
        <property name="useZKSwitch">true</property>

    </system>
   
    <!-- 全局SQL防火墙设置 -->
    <!--
    <firewall>
       <whitehost>
          <host host="127.0.0.1" user="mycat"/>
          <host host="127.0.0.2" user="mycat"/>
       </whitehost>
       <blacklist check="false">
       </blacklist>
    </firewall>
    -->
   
    <user name="root">
        <property name="password">123456</property>
        <property name="schemas">thesisdb</property>
    </user>

    <user name="user">
        <property name="password">user</property>
        <property name="schemas">thesisdb</property>
        <property name="readOnly">true</property>
    </user>

</mycat:server>

-----------------------------------------------------------------------------------------------

红色部分表示mycat的账号为root，密码123456，逻辑数据库为thesisdb

-------------------------------------------------------------------------------------------------------------

schema.xml：

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">

        <schema name="thesisdb" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1">

</schema>

<dataNode name="dn1" dataHost="localhost1" database="thesisdb" />

<dataHost name="localhost1" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">

<heartbeat>select user()</heartbeat>

<writeHost host="hostM1" url="127.0.0.1:3306" user="root" password="123456">

<readHost host="hostS1" url="127.0.0.1:3307" user="root" password="123456" />

                </writeHost>

        </dataHost>

 

</mycat:schema>

红色部分为物理服务器，hostM1为主，hostS1为从

那么访问mycat数据就是用户名root，密码123456，默认端口为8066，然后就按照普通的Mysql服务器那样去访问mycat。

二、SSH项目配置

一般使用框架都会用到事务，如果都要到事务那么就都会访问主服务器，达不到分离的效果，因此配置事务的时候要注意区分，比如只对包含增删改的进行事务配置：

<!-- 配置事务管理器 -->
    <bean name="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>

    <!-- 拦截器方式配置-->
    <tx:advice id="transactionAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="add*" />
            <tx:method name="save*" />
            <tx:method name="update*" propagation="REQUIRED" />
            <tx:method name="modify*" />
            <tx:method name="edit*" />
            <tx:method name="delete*" />
            <tx:method name="remove*" />
            <tx:method name="repair" />
            <tx:method name="deleteAndRepair" />
        </tx:attributes>
    </tx:advice>
    <aop:config>
        <aop:pointcut id="transactionPointcut" expression="execution(* com.kpt.service..*Impl.*(..))" />
        <aop:advisor pointcut-ref="transactionPointcut" advice-ref="transactionAdvice" />
    </aop:config>