MyCat 全局表 | Eddie'Blog
MyCat 全局表

MyCat 全局表

eddie 505 2020-11-05

目录

全局表

一、描述

之前说的都是分片表，水平拆分到不同的库表。但是如果存在一个情况，不用分片的表(字典表，省份表)。

比如用户需要获取省份的数据，如果分片了，又要想办法去关联获取省份的数据，就很麻烦。 使用全局表功能，就只关联自己的分片库即可实现。避免跨库这些麻烦操作！

二、schema.xml配置

  • type属性：global为全局表 ，不指定则为分片表
[root@localhost bin]# cat /opt/mycat/conf/schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">

        <schema name="user" checkSQLschema="true" sqlMaxLimit="100">
                <!-- auto sharding by id (long) -->
                <table name="user" dataNode="dn246,dn247" rule="mod-long" />
                <!-- 全局表 -->
                <table name="province" dataNode="dn246,dn247" type="global"/>

                <!-- <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="dn246" dataHost="db246" database="user_246" />
        <dataNode name="dn247" dataHost="db247" database="user_247" />
        <!-- <dataNode name="dn3" dataHost="localhost1" database="db3" />  -->

        <!--<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="db246" 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="M1" url="192.168.8.246:3306" user="eddie" password="Abc@123456">
                        <readHost host="S1" url="192.168.8.245:3306" user="eddie" password="Abc@123456" /> 
                </writeHost>

                <!-- <writeHost host="M2" url="192.168.8.245:3306" user="eddie" password="Abc@123456"/> -->

                <!-- <writeHost host="hostS1" url="localhost:3316" user="root"
                                   password="123456" /> -->

                <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
        </dataHost>

        <dataHost name="db247" 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="M1" url="192.168.8.247:3306" user="eddie"
                                   password="Abc@123456">
                        <!-- can have multi read hosts -->
                        <!-- <readHost host="hostS2" url="192.168.1.200:3306" user="root" password="xxx" /> -->
                </writeHost>
                <!-- <writeHost host="hostS1" url="192.168.8.247:3316" user="root"
                                                        password="123456" /> -->

                <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->
        </dataHost>


        <!--
                <dataHost name="sequoiadb1" maxCon="1000" minCon="1" balance="0" dbType="sequoiadb" dbDriver="jdbc">
                <heartbeat>             </heartbeat>
                 <writeHost host="hostM1" url="sequoiadb://1426587161.dbaas.sequoialab.net:11920/SAMPLE" user="jifeng"  password="jifeng"></writeHost>
                 </dataHost>

          <dataHost name="oracle1" maxCon="1000" minCon="1" balance="0" writeType="0"   dbType="oracle" dbDriver="jdbc"> <heartbeat>select 1 from dual</heartbeat>
                <connectionInitSql>alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss'</connectionInitSql>
                <writeHost host="hostM1" url="jdbc:oracle:thin:@127.0.0.1:1521:nange" user="base"       password="123456" > </writeHost> </dataHost>

                <dataHost name="jdbchost" maxCon="1000"         minCon="1" balance="0" writeType="0" dbType="mongodb" dbDriver="jdbc">
                <heartbeat>select       user()</heartbeat>
                <writeHost host="hostM" url="mongodb://192.168.0.99/test" user="admin" password="123456" ></writeHost> </dataHost>

                <dataHost name="sparksql" maxCon="1000" minCon="1" balance="0" dbType="spark" dbDriver="jdbc">
                <heartbeat> </heartbeat>
                 <writeHost host="hostM1" url="jdbc:hive2://feng01:10000" user="jifeng"         password="jifeng"></writeHost> </dataHost> -->

        <!-- <dataHost name="jdbchost" maxCon="1000" minCon="10" balance="0" dbType="mysql"
                dbDriver="jdbc"> <heartbeat>select user()</heartbeat> <writeHost host="hostM1"
                url="jdbc:mysql://localhost:3306" user="root" password="123456"> </writeHost>
                </dataHost> -->
</mycat:schema>

四、重载配置

mysql> reload @@config_all;
Query OK, 1 row affected (0.24 sec)
Reload config success

五、测试


-- 192.168.8.246 和 192.168.8.247 分别运行创表DDL
CREATE TABLE `province` (
  `province_id` int NOT NULL,
  `province_name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

-- MyCat - 192.168.8.245 运行插入语句
INSERT INTO `user`.`province`(`province_id`, `province_name`) VALUES (10000, '广州')

-- 查看 192.168.8.246 和 192.168.8.247 是否存在 (10000, '广州') 数据
SELECT * FROM `province` WHERE `province_id` = 10000 AND `province_name` = '广州' LIMIT 1

按测试来看，那么只需要在MyCAT进行操作，就会自动同步到其他的库表。

MySQL