mycat写库分片-526互联

之前的读写分离（一主一从）https://www.cnblogs.com/zwh0910/p/17267627.html

架构如下：

从该系统架构中，可以看出：

（1）、数据库从之前的单节点变为多节点提供服务

（2）、主节点数据，同步到从节点数据

（3）、应用程序需要连接到 2个数据库节点，并且在程序内部实现判断读写操作

但是上面的架构存在问题：所有操作都是将数据写入到主节点中，再同步到从节点。但是主节点只是一个单节点在存储数据，我们并没有解决数据存储量的问题，要想解决这个问题，必须采用分片，即有多个主节点，或者说多对主从节点，多个主节点看作是一个整体，可以把这多个主节点看作是一个大节点去存储数据

有两个数据库集群

MySQL集群1：

主机	端口	容器名称	角色
云服务器IP	3301	mysql-master	master
云服务器IP	3302	mysql-slave	slav

MySQL集群2：

主机	端口	容器名称	角色
云服务器IP	3401	mysql-master2	master
云服务器IP	3402	mysql-slave2	slav

下面的操作在这篇博客的基础上修改mycat配置：https://www.cnblogs.com/zwh0910/p/17267627.html#autoid-1-7-0

server.xml文件不用修改，配置如下：

<?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:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
    <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="ignoreUnknownCommand">0</property><!-- 0遇上没有实现的报文(Unknown command:),就会报错、1为忽略该报文，返回ok报文。
    在某些mysql客户端存在客户端已经登录的时候还会继续发送登录报文,mycat会报错,该设置可以绕过这个错误-->
    <property name="useHandshakeV10">1</property>
    <property name="removeGraveAccent">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="sqlExecuteTimeout">300</property>  <!-- SQL 执行超时 单位:秒-->
        <property name="sequnceHandlerType">1</property>
        <!--<property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property>
        INSERT INTO `travelrecord` (`id`,user_id) VALUES ('next value for MYCATSEQ_GLOBAL',"xxx");
        -->
        <!--必须带有MYCATSEQ_或者 mycatseq_进入序列匹配流程 注意MYCATSEQ_有空格的情况-->
        <property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property>
    <property name="subqueryRelationshipCheck">false</property> <!-- 子查询中存在关联查询的情况下,检查关联字段中是否有分片字段 .默认 false -->
    <property name="sequenceHanlderClass">io.mycat.route.sequence.handler.HttpIncrSequenceHandler</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="dataNodeIdleCheckPeriod">300000</property> 5 * 60 * 1000L; //连接空闲检查
            <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">0</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>
        <!--如果为0的话,涉及多个DataNode的catlet任务不会跨线程执行-->
        <property name="parallExecute">0</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="root" defaultAccount="true">
        <property name="password">123456</property>
        <property name="schemas">nacos_config</property>
        <property name="defaultSchema">nacos_config</property>
        <!--No MyCAT Database selected 错误前会尝试使用该schema作为schema，不设置则为null,报错 -->
        
        <!-- 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">nacos_config</property>
        <property name="readOnly">true</property>
        <property name="defaultSchema">nacos_config</property>
    </user>

</mycat:server>

修改schema.xml文件

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

    <schema name="nacos_config" checkSQLschema="true" sqlMaxLimit="100">
        <!-- auto sharding by id (long) -->
        <!--splitTableNames 启用<table name 属性使用逗号分割配置多个表,即多个表使用这个配置-->
        <table name="tb_ad,users" dataNode="dn1,dn2" rule="mod-long"/>
        <!-- <table name="oc_call" primaryKey="ID" dataNode="dn1$0-743" rule="latest-month-calldate"
            /> -->
    </schema>
    <!-- <dataNode name="dn1$0-743" dataHost="localhost1" database="db$0-743"
        /> -->
    <dataNode name="dn1" dataHost="localhost1" database="nacos_config" />
    <dataNode name="dn2" dataHost="localhost2" database="nacos_config" />
    <!--<dataNode name="dn4" dataHost="sequoiadb1" database="SAMPLE" />
     <dataNode name="jdbc_dn1" dataHost="jdbchost" database="db1" />
    <dataNode    name="jdbc_dn2" dataHost="jdbchost" database="db2" />
    <dataNode name="jdbc_dn3"     dataHost="jdbchost" database="db3" /> -->
    <dataHost name="localhost1" maxCon="1000" minCon="10" balance="3"
              writeType="1" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
        <heartbeat>select user()</heartbeat>
        <!-- can have multi write hosts -->
        <writeHost host="hostM1" url="localhost:3401" user="root"
                   password="123456">
             <readHost host="R1" url="localhost:3402" user="root" password="123456"/>
        </writeHost>
        <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
    </dataHost>
    <dataHost name="localhost2" maxCon="1000" minCon="10" balance="3"
                          writeType="1" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
                <heartbeat>select user()</heartbeat>
                <!-- can have multi write hosts -->
                <writeHost host="hostM2" url="localhost:3301" user="root"
                                   password="123456">
                         <readHost host="R2" url="localhost:3302" user="root" password="123456"/>
                </writeHost>
                <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
        </dataHost>
</mycat:schema>

修改rule.xml

<function name="mod-long" class="io.mycat.route.function.PartitionByMod">
        <!-- how many data nodes -->
        <property name="count">2</property>
    </function>

此时启动了四个mysql

CONTAINER ID   IMAGE          COMMAND                  CREATED        STATUS         PORTS                                                  NAMES
8c6de74fbbb9   mysql:8.0.26   "docker-entrypoint.s…"   18 hours ago   Up 18 hours    33060/tcp, 0.0.0.0:3402->3306/tcp, :::3402->3306/tcp   mysql-slave2
88af7650cb6f   mysql:8.0.26   "docker-entrypoint.s…"   18 hours ago   Up 16 hours    33060/tcp, 0.0.0.0:3401->3306/tcp, :::3401->3306/tcp   mysql-master2
3b754acc9a3e   mysql:8.0.26   "docker-entrypoint.s…"   3 days ago     Up 17 hours    33060/tcp, 0.0.0.0:3302->3306/tcp, :::3302->3306/tcp   mysql-slave
b21ba08b7665   mysql:8.0.26   "docker-entrypoint.s…"   3 days ago     Up 2 seconds   33060/tcp, 0.0.0.0:3301->3306/tcp, :::3301->3306/tcp   mysql-master

启动mycat

./mycat console

再执行脚本

./startup_nowrap.sh

现在我们来测试，在mycat中创建表

-- 创建表
CREATE TABLE `TB_AD` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`type` int(10) DEFAULT NULL COMMENT '广告类型',
`title` varchar(100) DEFAULT NULL COMMENT '描述',
`url` varchar(200) DEFAULT NULL COMMENT '图片URL地址',
`created` datetime DEFAULT NULL,
`updated` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT='广告表';

执行结果：

此时四个节点的nacos_config表中都有TB_AD表

插入数据

INSERT INTO `TB_AD` (`id`, `type`, `title`, `url`, `created`, `updated`) VALUES (1,
'1', 'UniCity万科天空之城', 'http://itcast-haoke.oss-cn-
qingdao.aliyuncs.com/images/2018/11/26/15432029097062227.jpg', '2018-11-26 11:28:49',
'2018-11-26 11:28:51');
INSERT INTO `TB_AD` (`id`, `type`, `title`, `url`, `created`, `updated`) VALUES (2,
'1', '天和尚海庭前', 'http://itcast-haoke.oss-cn-
qingdao.aliyuncs.com/images/2018/11/26/1543202958579877.jpg', '2018-11-26 11:29:27',
'2018-11-26 11:29:29');
INSERT INTO `TB_AD` (`id`, `type`, `title`, `url`, `created`, `updated`) VALUES (3,
'1', '[奉贤 南桥] 光语著', 'http://itcast-haoke.oss-cn-
qingdao.aliyuncs.com/images/2018/11/26/15432029946721854.jpg', '2018-11-26 11:30:04',
'2018-11-26 11:30:06');
INSERT INTO `TB_AD` (`id`, `type`, `title`, `url`, `created`, `updated`) VALUES (4,
'1', '[上海周边 嘉兴] 融创海逸长洲', 'http://itcast-haoke.oss-cn-
qingdao.aliyuncs.com/images/2018/11/26/15432030275359146.jpg', '2018-11-26 11:30:49',
'2018-11-26 11:30:53');