MyCat 讀寫分離,負載均衡

docker mysql 主從復制

配合Spring 事務 注意事項

 

配置好JRE，安裝好MYCAT

在mysql主庫創建表，會同步到從庫

CREATE TABLE `user` (
  `id` int(11) NOT NULL,
  `user` varchar(255) NOT NULL COMMENT '名稱',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

mycat schema.xml

balance="3"，所有讀請求隨機的分發到wiriterHost對應的readhost執行，writerHost不負擔讀壓力

switchType='-1'意味着當主掛掉的時候，不進行自動切換，即hostS1和hostS2並不會被提升為主，仍只提供讀的功能。

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
    <schema name="slavetest" checkSQLschema="false" sqlMaxLimit="10000">
        <!-- 測試表 -->
        <table name="user" primaryKey="id" dataNode="dn1" />
    </schema>
    <!-- <dataNode name="dn1$0-743" dataHost="localhost1" database="db$0-743"/> -->
    <dataNode name="dn1" dataHost="localhost1" database="slavetest" />
    <dataHost name="localhost1" maxCon="1000" minCon="1000" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="-1"  slaveThreshold="100">
        <heartbeat>select user()</heartbeat>
        <!-- can have multi write hosts -->
        <writeHost host="hostM1" url="192.168.1.9:3306" user="root" password="masterpwd">
            <!-- can have multi read hosts -->
            <readHost host="hostS2" url="192.168.1.9:3307" user="slave" password="slavepwd" />
        </writeHost>
    </dataHost>
</mycat:schema>

 

mycat server.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
    <system>
    <property name="useSqlStat">0</property>  <!-- 1為開啟實時統計、0為關閉 -->
    <property name="useGlobleTableCheck">0</property>  <!-- 1為開啟全加班一致性檢測、0為關閉 -->

        <property name="sequnceHandlerType">2</property>

        <property name="processorBufferPoolType">0</property>
        <property name="handleDistributedTransactions">0</property>
        
            <!--
            off heap for merge/order/group/limit      1開啟   0關閉
        -->
        <property name="useOffHeapForMerge">1</property>

        <!--
            單位為m
        -->
        <property name="memoryPageSize">1m</property>

        <!--
            單位為k
        -->
        <property name="spillsFileBufferSize">1k</property>

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

        <!--
            單位為m
        -->
        <property name="systemReserveMemorySize">384m</property>


        <!--是否采用zookeeper協調切換  -->
        <property name="useZKSwitch">true</property>


    </system>
    
    <user name="root">
        <property name="password">123456</property>
        <property name="schemas">slavetest</property>
    </user>

</mycat:server>

修改mycat log4j.xml 方便查看讀寫分離是否生效

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d [%-5p][%t] %m %throwable{full} (%C:%F:%L) %n"/>
        </Console>

        <RollingFile name="RollingFile" fileName="${sys:MYCAT_HOME}/logs/mycat.log"
                     filePattern="${sys:MYCAT_HOME}/logs/$${date:yyyy-MM}/mycat-%d{MM-dd}-%i.log.gz">
        <PatternLayout>
                <Pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %5p [%t] (%l) - %m%n</Pattern>
            </PatternLayout>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="250 MB"/>
                <TimeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>
    </Appenders>
    <Loggers>
        <asyncRoot level="debug" includeLocation="true">

            <AppenderRef ref="FILE" />
            <AppenderRef ref="RollingFile"/>

        </asyncRoot>
    </Loggers>
</Configuration>

重啟mycat 登錄mycat

root@0b763a8d1ddd:/# mysql -uroot -p123456 -h192.168.1.9 -P8066

插入測試數據

mysql> insert into user values(1,"laizhenwei");
Query OK, 1 row affected (0.01 sec)

mysql> select * from user limit 1;
+----+------------+
| id | user       |
+----+------------+
|  1 | laizhenwei |
+----+------------+
1 row in set (0.00 sec)

查看mycat日志