Mycat水平分表

环境说明

主机名	IP	角色	数据库
node1	192.168.114.129	Mycat	node_seq
node2	192.168.114.133	Mysql	student_db01 student_db02
node3	192.168.114.136	Mysql	student_db03 student_db04

实验

假设我们数据库中有一张学生表(stduent)，和一张学生详情表(student_detail)。因为数据量太大要分表，把原来一张表能够存储的数据，水平扩展到4个数据库中。

寻找分片字段

• 水平切分整张表，需要找一个分片键，作为分片的依据
• 分片后各个节点上的数据尽可能存储均匀
• 分片键最好是高频查询用到的查询条件
• 如果要分片的表还有子表，那么子表也应该使用ER表形式，把相关联数据分配到同一个分片节点上

创建表

#node2
create database student_db01 default charset utf8;
create database student_db02 default charset utf8;

#node3
create database student_db03 default charset utf8;
create database student_db04 default charset utf8;


#stduent01,student02,student03,student04 节点
CREATE TABLE `student` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(32) NOT NULL COMMENT '学生姓名',
  `class_id` bigint(20) NOT NULL DEFAULT '0' COMMENT '班级id',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='学生表';

CREATE TABLE `student_detail` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `student_id` varchar(32) NOT NULL COMMENT '学生表id',
  `address` varchar(50) DEFAULT '' COMMENT '学生地址',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='学生详情表';

分片配置用到的文件

• 使用schema.xml 配置逻辑库和逻辑表
• 使用rule.xml 配置分片表的分片规则
• 使用server.xml 配置访问用户及权限

配置 rule.xml

进行水平分片是才用到这个xml

<tableRule name="student_sharding">
    <rule>
        <columns>class_id</columns>
        <algorithm>mod-long</algorithm>
    </rule>
</tableRule>

配置全局唯一id

全局唯一id的用处是，即使主键是自增的情况下，保证各个节点不会出现重复主键

允许创建函数

vim my.conf
    log_bin_trust_function_creators=1

msql创建自增规则表

mysql> mysql -uroot -p
mysql> create database node_seq default charset utf8;

导入
mysql -uroot -p node_seq < /usr/local/mycat/conf/dbseq.sql

mysql > insert into MYCAT_SEQUENCE values('STUDENT',1,1);
mysql > insert into MYCAT_SEQUENCE values('STUDENT_DETAIL',1,1);

mysql > grant all on *.* to 'mycat_connect'@'192.168.114.%';
mysql > flush privileges;

修改配置

指定相关表和数据库之间的关系

 vim /usr/local/mycat/conf/sequence_db_conf.properties
    STUDENT=node_seq
    STUDENT_DETAIL=node_seq

server id生成方式

vim /usr/local/mycat/conf/server.xml
    <property name="sequnceHandlerType">1</property>
    <!-- sequnceHandlerType = 1 --- 表示采用数据库对象-->

配置

vim /usr/local/mycat/conf/schema.xml

<schema name="school_db" checkSQLschema="false" sqlMaxLimit="100">
   
	<table name="student" primaryKey="id" dataNode="student_db01,student_db02,student_db03,student_db04" rule="student_sharding" autoIncrement="true">
		<childTable name="student_detail" primaryKey="id" joinKey="student_id" parentKey="student_id" autoIncrement="true"></childTable>
	</table>

    
</schema>
	

<dataNode name="student_db01" dataHost="mysql133" database="student_db01" />
<dataNode name="student_db02" dataHost="mysql133" database="student_db02" />
<dataNode name="student_db03" dataHost="mysql136" database="student_db03" />
<dataNode name="student_db04" dataHost="mysql136" database="student_db04" />

<!--使用全角自增id-->
<dataNode name="node_seq" dataHost="mysql129" database="node_seq" />

<dataHost name="mysql133" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1">
		<heartbeat>select user()</heartbeat>
		<writeHost host="192.168.114.133" url="192.168.114.133:3306" user="mycat_connect" password="123456" />
</dataHost>
<dataHost name="mysql136" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1">
		<heartbeat>select user()</heartbeat>
		<writeHost host="192.168.114.136" url="192.168.114.136:3306" user="mycat_connect" password="123456" />
</dataHost>



<dataHost name="mysql129" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1">
            <heartbeat>select user()</heartbeat>
            <writeHost host="192.168.114.129" url="192.168.114.129:3306" user="mycat_connect" password="123456" />
</dataHost>
<!--autoIncrement = true 表示表开启全局自增id -->

配置 server.xml

<system>
                <property name="nonePasswordLogin">0</property> <!-- 0为需要密码登陆、1为不需要密码登陆 ,默认为0，设置为1则需要指定默认账户-->
                <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">1</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">4</property>
                <property name="charset">utf8</property>
                <property name="txIsolation">2</property>
                <property name="sqlExecuteTimeout">300</property>
                <property name="defaultMaxLimit">100</property>
                <property name="maxPacketSize">104857600</property>
                <property name="sqlInterceptor">io.mycat.server.interceptor.impl.StatisticsSqlInterceptor</property>
                <property name="sqlInterceptorType">UPDATE,DELETE,INSERT</property>
                <property name="sqlInterceptorFile">/tmp/sql.txt</property>
</system>

 <user name="mycat_connect" defaultAccount="true">
                <property name="password">123456</property>
                <property name="schemas">school_db</property>
</user>

重新启动mycat

mycat restart

验证

先清除以往订单
mysql -umycat_connect -p -h 192.168.114.129 -P 8066

插入数据

#student表中插入数据
insert into student(`name`,`class_id`) values('tom',1);
insert into student(`name`,`class_id`) values('lily',2);
insert into student(`name`,`class_id`) values('jack',4);
insert into student(`name`,`class_id`) values('json',3);
insert into student(`name`,`class_id`) values('hok',3);
insert into student(`name`,`class_id`) values('haolly',3);
insert into student(`name`,`class_id`) values('jerry',3);
insert into student(`name`,`class_id`) values('wrrol',3);
insert into student(`name`,`class_id`) values('brant',2);
insert into student(`name`,`class_id`) values('james',4);

#stduent_detail 中插入数据
填写真实的student_id
insert into student_detail(student_id,address) values('','北京');



#分别进入各个分片数据库中查看数据和分片对应情况 stduent_db01, stduent_db02, stduent_db03, stduent_db04
select id,mod(class_id,4) from student;
select student_id from student_detail;

#mycat 关联查询
select * from student as a join student_detail  b on a.id = b.student_id;