mycat的分库分表配置

之前配置过MySQL的搭建、主从复制、mycat的读写分离，接下来配置一下mycat的分库分表功能。
https://blog.csdn.net/baidu_41634343/article/details/109472549 MySQL主从复制
https://blog.csdn.net/baidu_41634343/article/details/109485894 mycat读写分离
其实mycat主要编辑的是conf目录下的schema.xml、rule.xml、server.xml、sequence_db_conf.properties四个文件。
schema.xml主要配置物理数据库的信息，逻辑数据库名称以及表和路由策略之间的关系等；
rule.xml主要配置路由策略、拆分规则等；
server.xml主要配置逻辑数据库的信息，包括用户名、密码、端口等，也是代码中数据库连接的地址；
sequence_db_conf.properties主要配置主键自增说明。

修改server.xml

我主要是修改了其中的用户名与密码 主要用于登录mycat

<?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. -->
        <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="useHandshakeV10">1</property>
        <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 | type 2 NettyBufferPool -->
                <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> -->
                <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">64k</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">false</property>

                <!-- XA Recovery Log日志路径 -->
                <!--<property name="XARecoveryLogBaseDir">./</property>-->

                <!-- XA Recovery Log日志名称 -->
                <!--<property name="XARecoveryLogBaseName">tmlog</property>-->
                <!--如果为 true的话 严格遵守隔离级别,不会在仅仅只有select语句的时候在事务中切换连接-->
                <property name="strictTxIsolation">false</property>

                <property name="useZKSwitch">true</property>

        </system>

        <!-- 全局SQL防火墙设置 -->
        <!--白名单可以使用通配符%或着*-->
        <!--例如<host host="127.0.0.*" user="root"/>-->
        <!--例如<host host="127.0.*" user="root"/>-->
        <!--例如<host host="127.*" user="root"/>-->
        <!--例如<host host="1*7.*" user="root"/>-->
        <!--这些配置情况下对于127.0.0.1都能以root账户登录-->
        <!--
        <firewall>
           <whitehost>
              <host host="1*7.0.0.*" user="root"/>
           </whitehost>
       <blacklist check="false">
       </blacklist>
        </firewall>
        -->

        <user name="mycat" defaultAccount="true">
                <property name="password">123456</property>
                <property name="schemas">TESTDB</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">TESTDB</property>
                <property name="readOnly">true</property>
        </user>

</mycat:server>

修改rule.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:rule SYSTEM "rule.dtd">
<mycat:rule xmlns:mycat="http://io.mycat/">
        <!--枚举规则-->
        <tableRule name="auto-sharding-long">
                <rule>
                        <columns>id</columns>
                        <algorithm>rang-long</algorithm>
                </rule>
        </tableRule>
	<!-- PartitionByMod求模法 -->
   <function name="rang-long" class="io.mycat.route.function.PartitionByMod">
    <property name="count">3</property><!-- 这里是schema.xml中有三个库所以这里填写3 -->
</function>

<!--    <function name="rang-long" class="io.mycat.route.function.AutoPartitionByLong">
                <property name="mapFile">autopartition-long.txt</property>
        </function>
 -->
</mycat:rule>

修改schema.xml

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

        <schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">
        		<!-- t_User对应的数据库表    dataNode对应的数据库的库名--这里是三个库  rule对应rule.xml中的分片规则-->
                <table name="t_user" primaryKey="id" autoIncrement="true" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />
        </schema>
        <dataNode name="dn1" dataHost="localhost1" database="db1" />
        <dataNode name="dn2" dataHost="localhost1" database="db2" />
        <dataNode name="dn3" dataHost="localhost1" database="db3" />
        <dataHost name="localhost1" maxCon="1000" minCon="10" 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="192.168.31.113:3306" user="root"
                                   password="123456">
                        <!-- can have multi read hosts -->
                        <readHost host="hostS1" url="192.168.31.114:3306" user="root" password="123456" />
                </writeHost>
        </dataHost>
</mycat:schema>

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
数据库的垂直与水平拆分
数据库垂直拆分：
分库：其实就是把不同业务模块分到不同的数据库（可以每个库都在一个实例里，也可以每个库在不同实例里）中去。

数据库水平拆分
在单机上：可以看成是分表，把一个大表，拆分成多个表结构相同的表来共同存储表数据
在多机上：这种叫做分库分表，也就是说在单表水平分表的情况下，把每一个分的表都放到一个库（实例上去）上去。


mycat的优缺点： https://blog.csdn.net/yinni11/article/details/82707757
mycat的分片规则： https://www.cnblogs.com/756623607-zhang/p/6656022.html

mycat的官方网站可以查看 http://www.mycat.org.cn/ 《Mycat权威指南》进行详解。