mycat实现分库分表（雪花算法唯一主键）

最新推荐文章于 2024-06-02 22:32:10 发布

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最新推荐文章于 2024-06-02 22:32:10 发布

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分类专栏： mycat 文章标签： mycat

本文链接：https://blog.youkuaiyun.com/pycharm_u/article/details/102372346

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一、前言

数据库数据达到百万级的数量时，数据库的性能就会下降，这样就引出了分库分表的概念，将数据存入不同的数据库中。在本文中，将以mycat为例实现分库分表。

二、mycat配置

1.server.xml配置

<!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">USER</property>
		
		<!-- 表级 DML 权限设置 -->
		<!-- 		
		<privileges check="false">
			<schema name="TESTDB" dml="0110" >
				<table name="tb01" dml="0000"></table>
				<table name="tb02" dml="1111"></table>
			</schema>
		</privileges>		
		 -->
	</user>

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

</mycat:server>

schemas：虚拟表的名称，可以改写，但是必须和schema中的虚拟表名称一致。

2.schema.xml配置

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

	<schema name="USER" checkSQLschema="false" sqlMaxLimit="100">
		<table name="user" primaryKey="ID" dataNode="dn1,dn2"
			   rule="mod-long" />
	</schema>
	<dataNode name="dn1" dataHost="localhost1" database="db01" />
	<dataNode name="dn2" dataHost="localhost1" database="db02" />
	<dataHost name="localhost1" maxCon="1000" minCon="10" balance="0"
			  writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
		<heartbeat>select user()</heartbeat>
		<!-- can have multi write hosts -->
		<writeHost host="hostM1" url="localhost:3306" user="root"
				   password="123456">
			<!-- can have multi read hosts -->
			<readHost host="hostS2" url="localhost:3306" user="root" password="123456" />
		</writeHost>
	</dataHost>
</mycat:schema>

配置分片以及映射关系的配置文件。

3.rule.xml配置

<!DOCTYPE mycat:rule SYSTEM "rule.dtd">
<mycat:rule xmlns:mycat="http://io.mycat/">
	<tableRule name="mod-long">
		<rule>
			<columns>ID</columns>
			<algorithm>mod-long</algorithm>
		</rule>
	</tableRule>
	
	<function name="mod-long" class="io.mycat.route.function.PartitionByMod">
		<!-- how many data nodes -->
		<property name="count">2</property>
	</function>
</mycat:rule>

三、数据库

CREATE TABLE `user` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `username` varchar(20) NOT NULL,
  `password` varchar(64) NOT NULL,
  `create_time` varchar(30) DEFAULT NULL,
  `last_login_time` varchar(30) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `user_id_uindex` (`id`),
  UNIQUE KEY `user_username_uindex` (`username`)
) ENGINE=InnoDB AUTO_INCREMENT=378894585638047751 DEFAULT CHARSET=utf8;

在localhost创建两个库db01,db02，与上面scmehe中的databse对应。