使用mycat 对数据库做分库

• 首先这边是有四个测试库环境 两台在3.10 两台在3.125  
• mycat 分片常用的规则 https://blog.csdn.net/tototuzuoquan/article/details/80362892
• 关于mycat的核心配置有三个xml 文件分别是rule 、server、schema 下面分别是我这边三个xml的配置

  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE mycat:rule SYSTEM "rule.dtd">
  <mycat:rule xmlns:mycat="http://io.mycat/">
      <tableRule name="sharding-by-mod"> 
          <rule> 
               <!--属性指定对应表中用于分片的列名-->
              <columns>uid</columns> 
               <!--属性对应function 中指定的算法的名称-->
              <algorithm>sharding-by-mod</algorithm> 
          </rule> 
  
      </tableRule>        
      <tableRule name="sharding-by-murmur-userid">
                      <rule>
                                 <columns>Id</columns>
                              <algorithm>sharding-by-murmur-userid</algorithm>
                      </rule>
      </tableRule>
      <tableRule name="sharding-by-murmur-fzid">
                      <rule>
                                 <columns>FzId</columns>
                              <algorithm>sharding-by-murmur-userid</algorithm>
                      </rule>
      </tableRule>
      <function name="sharding-by-mod" class="io.mycat.route.function.PartitionByMod">
                 <!-- 共有多少个节点 -->
                   <property name="count">4</property>
          </function>
      <function name="sharding-by-murmur-userid" class="io.mycat.route.function.PartitionByMurmurHash">
          <property name="seed">0</property><!-- 默认是0 -->
          <property name="count">4</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
          <property name="virtualBucketTimes">160</property><!-- 一个实际的数据库节点被映射为这么多虚拟节点，默认是160倍，也就是虚拟节点数是物理节点数的160倍 -->
          <!-- <property name="weightMapFile">weightMapFile</property> 节点的权重，没有指定权重的节点默认是1。以properties文件的格式填写，以从0开始到count-1的整数值也就是节点索引为key，以节点权重值为值。>所有权重值必须是正整数，否则以1代替 -->
          <!-- <property name="bucketMapPath">/usr/local/mycat/logs/bucketMapPath-murmur-userid</property>
          用于测试时观察各物理节点与虚拟节点的分布情况，如果指定了这个属性，会把虚拟节点的murmur hash值与物理节点的映射按行输出到这个文件，没有默认值，如果不指定，就不会输出任何东西 -->
      </function>
  </mycat:rule>

  <?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="processorBufferPoolType">0</property>                                              
          <property name="serverPort">8066</property>      <!-- 8066 为连接mycat的端口-->                                         
          <property name="managerPort">9066</property>       <!-- 9066 为连接mycat管理地址的端口-->                 
          <property name="idleTimeout">300000</property> 
          <property name="bindIp">0.0.0.0</property>                        
          <property name="frontWriteQueueSize">4096</property> 
          <property name="processors">32</property>                
          <property name="handleDistributedTransactions">0</property>                
          <property name="useOffHeapForMerge">1</property>                
          <property name="memoryPageSize">1m</property>                
          <property name="spillsFileBufferSize">1k</property>                
          <property name="useStreamOutput">0</property>                
          <property name="systemReserveMemorySize">384m</property>                
          <property name="useZKSwitch">true</property>        
      </system>        
      <!-- 配置连接mycat的账号密码, 和逻辑库名称, 可以设置多个-->        
      <user name="root">                
          <property name="password">123456</property>          
           <!-- 多个数据库用英文逗号隔开-->     
          <property name="schemas">test,fzuser</property>        
      </user>        
  
      <user name="user">                
          <property name="password">123456</property>                
          <property name="schemas">test</property>                
          <property name="readOnly">true</property>        
      </user>
  
  </mycat:server>

  <?xml version="1.0"?>
  <!DOCTYPE mycat:schema SYSTEM "schema.dtd">
  <mycat:schema xmlns:mycat="http://io.mycat/">
  
      <!-- name="TESTDB"是在server.xml中配置<property name="schemas">TESTDB</property>-->
      <schema name="test" checkSQLschema="false" sqlMaxLimit="100"  >
          <table name="tb_user" dataNode="dn1,dn2,dn3,dn4" rule="sharding-by-mod" primaryKey="uid"/>
         <table name="tb_user_area" dataNode="dn1,dn2,dn3,dn4" rule="sharding-by-mod" primaryKey="aid"/>
      </schema>
      
      <schema name="fzuser" checkSQLschema="false" sqlMaxLimit="100"  >
          <table name="tb_account" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-fzid" primaryKey="FzId"/>
          <table name="tb_parent_student_relation" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id"/>
          <table name="tb_student_class" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id"/>
          <table name="tb_teacher_class" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id"/>
          <table name="tb_third_account" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id"/>
          <table name="tb_user" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id"/>
      </schema>
      <!--配置mysql数据库testdb2,cespimp_hazard  mycat逻辑库名为 dn1,dn2,dn3-->
      <dataNode name="dn1" dataHost="dataHost01" database="mycat1" />
      <dataNode name="dn2" dataHost="dataHost01" database="mycat2" />
      <dataNode name="dn3" dataHost="dataHost02" database="mycat3" />
      <dataNode name="dn4" dataHost="dataHost02" database="mycat4" /> 
      
      <dataNode name="user1" dataHost="dataHost01" database="fz_platform_userdata" />
      <dataNode name="user2" dataHost="dataHost01" database="fz_platform_userdata2" />
      <dataNode name="user3" dataHost="dataHost02" database="fz_platform_userdata3" />
      <dataNode name="user4" dataHost="dataHost02" database="fz_platform_userdata4" /> 
      
      
      <!--配置数据类型 balance="0"读写不分离 -->
      <dataHost name="dataHost01" maxCon="1000" minCon="10" balance="0"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1" slaveThreshold="100">
              <!--心跳包 -->
              <heartbeat>select user()</heartbeat>
              <!--配置mysql数据 账户密码 -->
              <writeHost host="hostM1" url="192.168.3.125:3306" user="root" password="k8-sgM&amp;W" />
      </dataHost>
  
     <!--配置数据类型 balance="0"读写不分离 -->
      <dataHost name="dataHost02" maxCon="1000" minCon="10" balance="0"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1" slaveThreshold="100">
              <!--心跳包 -->
              <heartbeat>select user()</heartbeat>
              <!--配置mysql数据 账户密码 -->
              <writeHost host="hostM2" url="192.168.3.10:3306" user="root" password="123456" />
      </dataHost>
  
  </mycat:schema>

   如果是需要使用到join 建议使用E R 分片

• <?xml version="1.0"?>
  <!DOCTYPE mycat:schema SYSTEM "schema.dtd">
  <mycat:schema xmlns:mycat="http://io.mycat/">
  
      <!-- name="TESTDB"是在server.xml中配置<property name="schemas">TESTDB</property>-->
      <schema name="test" checkSQLschema="false" sqlMaxLimit="100"  >
                  <table name="tb_user" dataNode="dn1,dn2,dn3,dn4" rule="sharding-by-mod" primaryKey="uid"/>
             <table name="tb_user_area" dataNode="dn1,dn2,dn3,dn4" rule="sharding-by-mod" primaryKey="aid"/>
      </schema>
      <schema name="fzuser" checkSQLschema="false" sqlMaxLimit="100"  >
                  <table name="tb_account" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-fzid" primaryKey="FzId"/>
                  <table name="tb_user" dataNode="user1,user2,user3,user4" rule="sharding-by-murmur-userid" primaryKey="Id">
                          <childTable  name="tb_student_class" joinKey="StudentId" parentKey="Id"  primaryKey="Id"/>
                          <childTable  name="tb_teacher_class" joinKey="TeacherId" parentKey="Id"  primaryKey="Id"/>
                          <childTable  name="tb_parent_student_relation" joinKey="StudentId" parentKey="Id"  primaryKey="Id"/>
                          <childTable  name="tb_third_account" joinKey="UserId" parentKey="Id" primaryKey="Id"/>
                          <childTable  name="tb_use_product" joinKey="UserId" parentKey="Id" primaryKey="Id"/>
                          <childTable  name="tb_user_mergelog" joinKey="UserId" parentKey="Id" primaryKey="Id"/>
                  </table>
      </schema>
  
      <!--配置mysql数据库testdb2,cespimp_hazard  mycat逻辑库名为 dn1,dn2,dn3-->
      <dataNode name="dn1" dataHost="dataHost01" database="mycat1" />
      <dataNode name="dn2" dataHost="dataHost01" database="mycat2" />
      <dataNode name="dn3" dataHost="dataHost02" database="mycat3" />
      <dataNode name="dn4" dataHost="dataHost02" database="mycat4" />
  
      <dataNode name="user1" dataHost="dataHost01" database="fz_platform_userdata" />
      <dataNode name="user2" dataHost="dataHost01" database="fz_platform_userdata2" />
      <dataNode name="user3" dataHost="dataHost02" database="fz_platform_userdata3" />
      <dataNode name="user4" dataHost="dataHost02" database="fz_platform_userdata4" />
  
  
      <!--配置数据类型 balance="0"读写不分离 -->
      <dataHost name="dataHost01" maxCon="1000" minCon="10" balance="0"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1" slaveThreshold="100">
              <!--心跳包 -->
              <heartbeat>select user()</heartbeat>
              <!--配置mysql数据 账户密码 -->
              <writeHost host="hostM1" url="192.168.3.125:3306" user="root" password="k8-sgM&amp;W" />
      </dataHost>
  
     <!--配置数据类型 balance="0"读写不分离 -->
      <dataHost name="dataHost02" maxCon="1000" minCon="10" balance="0"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1" slaveThreshold="100">
              <!--心跳包 -->
              <heartbeat>select user()</heartbeat>
              <!--配置mysql数据 账户密码 -->
              <writeHost host="hostM2" url="192.168.3.10:3306" user="root" password="123456" />
      </dataHost>
  
  </mycat:schema>
  ~                     

• 然后使用mysql客户端链接工具使用 server.xml 配置好的账号密码进行登录 。mycat端口默认是8066