Hi！我是小小，一个双鱼座的佛系程序猿，今日的blog将会写关于MyCat最后一点学习内容，读写分离，与MyCat实际应用案例和一个小小的例子。

MyCat 读写分离

MyCat的读写分离是建立在MySQL主从复制基础之上实现的，所以必须先搭建MySQL的主从复制。数据库读写分离对于大型系统或者访问量很高的互联网应用来说，是必不可少的一个重要功能。对于MySQL来说，标准的读写分离是主从模式，一个写节点Master后面跟着多个读节点，读节点的数量取决于系统的压力，通常是1-3个读节点的配置Mycat实现的读写分离和自动切换机制，需要mysql的主从复制机制配合。

MyCat 配置

Mycat 1.4 支持MySQL主从复制状态绑定的读写分离机制，让读更加安全可靠，配置如下：

<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="1" writeType="0" dbType="mysql" dbDriver="native" switchType="2" slaveThreshold="100"><heartbeat>show slave status</heartbeat><writeHost host="hostM" url="192.168.25.134:3306" user="root" password="root"><readHost host="hostS" url="192.168.25.166:3306" user="root" password="root" /></writeHost>
</dataHost>

(1) 设置 balance="1"与writeType="0"

Balance参数设置：

1. balance=“0”, 所有读操作都发送到当前可用的writeHost上。

2. balance=“1”，所有读操作都随机的发送到readHost。3. balance=“2”，所有读操作都随机的在writeHost、readhost上分发

WriteType参数设置：

1. writeType=“0”, 所有写操作都发送到可用的writeHost上。

2. writeType=“1”，所有写操作都随机的发送到readHost。3. writeType=“2”，所有写操作都随机的在writeHost、readhost分上发。

“readHost是从属于writeHost的，即意味着它从那个writeHost获取同步数据，因此，当它所属的writeHost宕机了，则它也不会再参与到读写分离中来，即“不工作了”，这是因为此时，它的数据已经“不可靠”了。基于这个考虑，目前mycat 1.3和1.4版本中，若想支持MySQL一主一从的标准配置，并且在主节点宕机的情况下，从节点还能读取数据，则需要在Mycat里配置为两个writeHost并设置banlance=1。”

(2) 设置 switchType="2" 与slaveThreshold="100"

switchType 目前有三种选择：-1：表示不自动切换1：默认值，自动切换2：基于MySQL主从同步的状态决定是否切换Mycat心跳检查语句配置为 show slave status ，dataHost 上定义两个新属性：switchType="2" 与slaveThreshold="100"，此时意味着开启MySQL主从复制状态绑定的读写分离与切换机制。Mycat心跳机制通过检测 show slave status 中的 "Seconds_Behind_Master", "Slave_IO_Running","Slave_SQL_Running" 三个字段来确定当前主从同步的状态以及Seconds_Behind_Master主从复制时延。

项目案例

案例图

schema.xml

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/"><schema name="db_store" checkSQLschema="false" sqlMaxLimit="100"><table name="tstore" dataNode="dn_store" primaryKey="ID" /></schema><schema name="db_user" checkSQLschema="false" sqlMaxLimit="100"><!-- global table is auto cloned to all defined data nodes ,so can joinwith any table whose sharding node is in the same data nodejoinKey ：外键parentKey ：指向外键的主键（tuser表）--><table name="tcode" primaryKey="ID" type="global"dataNode="dn_user1,dn_user2" /><table name="tuser" primaryKey="ID" dataNode="dn_user$1-2"rule="mod_userId_long"><childTable name="tuaddress" primaryKey="ID" joinKey="uid"parentKey="id" /></table></schema><dataNode name="dn_store" dataHost="storeHost" database="db_store" /><dataNode name="dn_user1" dataHost="userHost1" database="db_user" /><dataNode name="dn_user2" dataHost="userHost2" database="db_user" /><!--Node Server1 balance=1 M/S --><dataHost name="storeHost" maxCon="1000" minCon="10" balance="1"writeType="0" dbType="mysql" dbDriver="native"switchType="2" slaveThreshold="100"><heartbeat>select user()</heartbeat><!-- can have multi write hosts --><writeHost host="hostM1" url="192.168.24.128:3306" user="root"password="root"><!-- can have multi read hosts --><readHost host="hostS1" url="192.168.24.129:3306"user="root" password="root" /></writeHost></dataHost><!--Node Server2 --><dataHost name="userHost1" 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="user_host1" url="192.168.24.128:3306" user="root"password="root" ></writeHost></dataHost><!--Node Server3 --><dataHost name="userHost2" 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="user_host2" url="192.168.24.129:3306"user="root"password="root"></writeHost></dataHost>
</mycat:schema>

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/"><tableRule name="rule1"><rule><columns>id</columns><algorithm>func1</algorithm></rule></tableRule><tableRule name="rule2"><rule><columns>user_id</columns><algorithm>func1</algorithm></rule></tableRule><tableRule name="sharding-by-intfile"><rule><columns>sharding_id</columns><algorithm>hash-int</algorithm></rule></tableRule><tableRule name="auto-sharding-long"><rule><columns>id</columns><algorithm>rang-long</algorithm></rule></tableRule><tableRule name="mod_userId_long"><rule><columns>id</columns><algorithm>mod-long</algorithm></rule></tableRule><tableRule name="sharding-by-murmur"><rule><columns>id</columns><algorithm>murmur</algorithm></rule></tableRule><tableRule name="crc32slot"><rule><columns>id</columns><algorithm>crc32slot</algorithm></rule></tableRule><tableRule name="sharding-by-month"><rule><columns>create_time</columns><algorithm>partbymonth</algorithm></rule></tableRule><tableRule name="latest-month-calldate"><rule><columns>calldate</columns><algorithm>latestMonth</algorithm></rule></tableRule><tableRule name="auto-sharding-rang-mod"><rule><columns>id</columns><algorithm>rang-mod</algorithm></rule></tableRule><tableRule name="jch"><rule><columns>id</columns><algorithm>jump-consistent-hash</algorithm></rule></tableRule><tableRule name="mod_userId_long"><rule><columns>id</columns><algorithm>mod-long</algorithm></rule></tableRule><function name="murmur"class="io.mycat.route.function.PartitionByMurmurHash"><property name="seed">0</property><!-- 默认是0 --><property name="count">2</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">/etc/mycat/bucketMapPath</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><function name="crc32slot"class="io.mycat.route.function.PartitionByCRC32PreSlot"><property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 --></function><function name="hash-int"class="io.mycat.route.function.PartitionByFileMap"><property name="mapFile">partition-hash-int.txt</property></function><function name="rang-long"class="io.mycat.route.function.AutoPartitionByLong"><property name="mapFile">autopartition-long.txt</property></function><function name="mod-long" class="io.mycat.route.function.PartitionByMod"><!-- how many data nodes --><property name="count">2</property></function><function name="func1" class="io.mycat.route.function.PartitionByLong"><property name="partitionCount">8</property><property name="partitionLength">128</property></function><function name="latestMonth"class="io.mycat.route.function.LatestMonthPartion"><property name="splitOneDay">24</property></function><function name="partbymonth"class="io.mycat.route.function.PartitionByMonth"><property name="dateFormat">yyyy-MM-dd</property><property name="sBeginDate">2015-01-01</property></function><function name="rang-mod"class="io.mycat.route.function.PartitionByRangeMod"><property name="mapFile">partition-range-mod.txt</property></function><function name="jump-consistent-hash"class="io.mycat.route.function.PartitionByJumpConsistentHash"><property name="totalBuckets">3</property></function>
</mycat:rule>

server.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: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">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> 进程数<property name="processorExecutor">32</property> 线程数--><!--默认为type 0: DirectByteBufferPool | type 1 ByteBufferArena--><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> <propertyname="managerPort">9066</property><property name="idleTimeout">300000</property> <propertyname="bindIp">0.0.0.0</property><property name="frontWriteQueueSize">4096</property> <propertyname="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">1</property><!--单位为m--><property name="memoryPageSize">1m</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">true</property></system><!-- 全局SQL防火墙设置 --><!--<firewall><whitehost> 白名单<host host="127.0.0.1" user="mycat"/><host host="127.0.0.2" user="mycat"/></whitehost>黑名单<blacklist check="false"></blacklist></firewall>--><user name="root"><property name="password">123456</property><property name="schemas">db_store,db_user</property><!-- 表级 DML 权限设置 --><!--<privileges check="false"> IUSD （1：可操作0：不可操作）<schema name="TESTDB" dml="0110" ><table name="tb01" dml="0000"></table><table name="tb02" dml="1111"></table></schema></privileges>--></user>
</mycat:server>

步骤：

1、先做好主从复制 2、在主库建立数据库db_user,db_store 3、从库同步db_user,db_store 4、按照上面的配置文件配置mycat,连接mycat 5、在db_store中建表tstore、并插入数据6、在db_user中建表tcode、tuser、tuaddress并插入数据

实例

用户购物下单实践

需求

需求：把订单信息分片，商家要查询出售的订单，用户要查询自己的订单。表设计：用户、商家订单、订单明细、用户订单分片规则：“用户表”---user_id 取模，“商家订单”----seller_user_id 取模“订单明细”----“商家订单”ER 分片，“买家订单”----buyer_user_id 取模

业务表

CREATE TABLE tb_user (login_name VARCHAR (32) comment '登录名',user_id BIGINT comment '用户标识',TYPE INT comment '用户类型 1 商家，2买家',passwd VARCHAR (128) comment '密码',primary key (user_id)) ;alter table tb_user comment '用户表';CREATE TABLE tb_seller_order (seller_user_id BIGINT comment '商家标识',buyer_user_id BIGINT comment '用户标识',order_id BIGINT comment '订单标识',price BIGINT comment '价格',STATUS INT comment '状态',primary key (order_id));alter table tb_seller_order comment '商家订单表';CREATE TABLE tb_order_detail(seller_user_id BIGINT comment '商家标识',order_detail_id BIGINT comment '订单明细标识',order_id BIGINT comment '订单标识',goods_id BIGINT comment '标识',goods_name VARCHAR(32) comment '商品名称',cnt INT comment '数量',unit_price INT comment '单价',primary key (order_detail_id));alter table tb_order_detail comment '订单明细';CREATE TABLE tb_buyer_order (buyer_user_id BIGINT comment '用户标识',seller_user_id BIGINT comment '商家标识',order_id BIGINT comment '订单标识',price BIGINT comment '价格',STATUS INT comment '状态',primary key (order_id));alter table tb_buyer_order comment '买家订单';

服务器分配

MySql

主 192.168.10.135
主 192.168.10.136
主 192.168.10.137

mycat：

192.168.10.137

表主键生成策略

使用mycat全局序列生成（mycat 全局序列号：http://blog.csdn.net/convict_eva/article/details/5191

添加MyCat全局序列号

USER_ID_SQUE=dn_master
ORDER_ID_SQUE=dn_master
DETAIL_ID_SQUE=dn_master

在dn_master结点执行：

insert into MYCAT_SEQUENCE(NAME,current_value,increment)
values('USER_ID_SQUE',1,100),('ORDER_ID_SQUE',1,100),('DETAIL_ID_SQUE',1,100);

重启mycat测试：

SELECT NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE;
SELECT NEXT VALUE FOR MYCATSEQ_ORDER_ID_SQUE;
SELECT NEXT VALUE FOR MYCATSEQ_DETAIL_ID_SQUE;

rule.xml配置

配置function 标签

找到function 标签name="mod-long" 的function 配置，修改总结点数为3（和使用的mysql 结点数一致）。

<function name="mod-long"
class="org.opencloudb.route.function.PartitionByMod">
<!-- how many data nodes -->
<property name="count">3</property>
</function>

配置tableRule标签

注意事项：name 要全局唯一rule.xml 配置添加如下配置

<!-- user分片规则 -->
<tableRule name="tb_user_mod-long"><rule><!-- 分片使用的字段 --><columns>user_id</columns><!-- 分片使用的方法，对应function 名称 --><algorithm>mod-long</algorithm></rule>
</tableRule><!-- 卖家订单分片规则 -->
<tableRule name="seller_order_mod-long">
<rule><columns>seller_user_id</columns><algorithm>mod-long</algorithm>
</rule>
</tableRule><!-- 买家订单分片规则 -->
<tableRule name="buyer_order_mod-long">
<rule><columns>buyer_user_id</columns><algorithm>mod-long</algorithm>
</rule>
</tableRule>

schema.xml 配置

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://org.opencloudb/"><schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100"><!-- auto sharding by id (long) --><table name="tb_a" dataNode="dn_master" /><!-- 全局表，使用type属性指定，多个结点要都执行建表语句。所有结点的数据一致。--><table name="tb_global_test"dataNode="dn_master,dn_master2,dn_master3" type="global" /><!-- 配置表所在的分片结点，指定主键和分片规则。指定主键是为了使用主键查询时mycat什么缓存主键对应的dn，提高查询效率。--><table name="tb_user" rule="tb_user_mod-long"primaryKey="user_id" dataNode="dn_master,dn_master2,dn_master3" /><table name="tb_seller_order" rule="seller_order_mod-long"primaryKey="order_id" dataNode="dn_master,dn_master2,dn_master3"><!-- 配置ER 分片，子表的存储依赖于主表，并且物理上紧邻存放。--><childTable name="tb_order_detail"primaryKey="order_detail_id" joinKey="order_id"parentKey="order_id" /></table><table name="tb_buyer_order" rule="buyer_order_mod-long"primaryKey="order_id" dataNode="dn_master,dn_master2,dn_master3" /></schema><!-- 配置数据结点 --><dataNode name="dn_master" dataHost="master"database="test_db" /><dataNode name="dn_master2" dataHost="master2"database="test_db" /><dataNode name="dn_master3" dataHost="master3"database="test_db" /><!-- ddata node host 配置 --><dataHost name="master" maxCon="1000" minCon="10" balance="3"writeType="0" dbType="mysql" dbDriver="native" switchType="1"slaveThreshold="100"><!-- 主从心跳语句配置 --><heartbeat>show slave status</heartbeat><writeHost host="hostM1" url="192.168.109.128:3306"user="root" password="Abc123!@#"><!-- 从库 --><readHost host="hostS2" url="192.168.109.130:3306"user="root" password="Abc123!@#" /></writeHost></dataHost><dataHost name="master2" maxCon="1000" minCon="10" balance="0"writeType="0" dbType="mysql" dbDriver="native" switchType="1"slaveThreshold="100"><heartbeat>select user()</heartbeat><writeHost host="hostM2" url="192.168.109.131:3306"user="root" password="Abc123!@#"></writeHost></dataHost><dataHost name="master3" maxCon="1000" minCon="10" balance="0"writeType="0" dbType="mysql" dbDriver="native" switchType="1"slaveThreshold="100"><heartbeat>select user()</heartbeat><writeHost host="hostM3" url="192.168.109.132:3306"user="root" password="Abc123!@#"></writeHost></dataHost>
</mycat:schema>

重启mycat，使用SQLyog连接到mycat，并执行建表语句。

测试

插入user

INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-1',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-2',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-3',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-4',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-5',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-6',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-7',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-8',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-9',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-10',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-11',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-12',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-13',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-14',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-15',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-16',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-17',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-18',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-19',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-20',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-21',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-22',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('name-23',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,1,'passwd-A');

查看插入的数据是否按照id取模分片。

下单测试

上面创建的是商家用户，下面创建买家用户。

INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('buyer-1',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,2,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('buyer-2',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,2,'passwd-A');
INSERT INTO `tb_user`(`login_name`,`user_id`,`TYPE`,`passwd`)
VALUES ('buyer-3',NEXT VALUE FOR MYCATSEQ_USER_ID_SQUE,2,'passwd-A');

所有的用户如下：mysql> select * from tb_user order by login_name; +------------+---------+------+----------+ | login_name | user_id | TYPE | passwd   | +------------+---------+------+----------+ | buyer-1    |  
248 |    2 | passwd-A | | buyer-2    |     249 |    2 | passwd-A | | buyer-3    |     250 |    2 | passwdA | | name-1     |     225 |    1 | passwd-A | | name-10    |     234 |    1 | passwd-A | | name-11    |    235 |    1 | passwd-A | | name-12    |     236 |    1 | passwd-A | | name-13    |     237 |    1 |passwd-A | | name-14    |     238 |    1 | passwd-A | | name-15    |     239 |    1 | passwd-A | |name-16    |     240 |    1 | passwd-A | | name-17    |     241 |    1 | passwd-A | | name-18    |  
242 |    1 | passwd-A | | name-19    |     243 |    1 | passwd-A | | name-2     |     226 |    1 |passwd-A | | name-20    |     244 |    1 | passwd-A | | name-21    |     245 |    1 | passwd-A | |name-22    |     246 |    1 | passwd-A | | name-23    |     247 |    1 | passwd-A | | name-3     |  
227 |    1 | passwd-A | | name-4     |     228 |    1 | passwd-A | | name-5     |     229 |    1 |passwd-A | | name-6     |     230 |    1 | passwd-A | | name-7     |     231 |    1 | passwd-A | |name-8     |     232 |    1 | passwd-A | | name-9     |     233 |    1 | passwd-A | +------------+---------+------+----------+

下单

SELECT NEXT VALUE FOR MYCATSEQ_ORDER_ID_SQUE;
INSERT INTO
`tb_seller_order`(`seller_user_id`,`buyer_user_id`,`order_id`,`price`)
VALUES (225,248,201,1222);
INSERT INTO `tb_order_detail`
(`seller_user_id`,`order_detail_id`,`order_id`,`goods_id`,`goods_name`,`cnt`,`un
it_price`)
VALUES (225, NEXT VALUE FOR MYCATSEQ_DETAIL_ID_SQUE,201,11,'goods_name',1,1220);
INSERT INTO `tb_order_detail`
(`seller_user_id`,`order_detail_id`,`order_id`,`goods_id`,`goods_name`,`cnt`,`un
it_price`)
VALUES (225, NEXT VALUE FOR MYCATSEQ_DETAIL_ID_SQUE,201,11,'goods_name2',1,2);

说明：商家225 在109.128 上，tb_seller_order表根据seller_user_id 取模分片，所有此订单数据存储在与user id为225 的商家同一分片 tb_order_detail 表使用的是与tb_seller_order ER 分片，使用order_id 关联，所以tb_order_detail 存储的分片与相同的order_id 的tb_seller_order 的数据在同一分片。再测试一条数据：user_id为238 的用户存储在109.131 分片上。

INSERT INTO
`tb_seller_order`(`seller_user_id`,`buyer_user_id`,`order_id`,`price`)
VALUES (238,248,203,1222);
INSERT INTO `tb_order_detail`
(`seller_user_id`,`order_detail_id`,`order_id`,`goods_id`,`goods_name`,`cnt`,`un
it_price`)
VALUES (238, NEXT VALUE FOR MYCATSEQ_DETAIL_ID_SQUE,203,11,'goods_name',1,1220);
INSERT INTO `tb_order_detail`
(`seller_user_id`,`order_detail_id`,`order_id`,`goods_id`,`goods_name`,`cnt`,`un
it_price`)
VALUES (238, NEXT VALUE FOR MYCATSEQ_DETAIL_ID_SQUE,203,11,'goods_name2',1,2);

测试结果：109.128数据为：mysql> select * from tb_user; +------------+---------+------+----------+ |login_name | user_id | TYPE | passwd   | +------------+---------+------+----------+ | name-1     |     225 |
1 | passwd-A | | name-4     |     228 |    1 | passwd-A | | name-7     |     231 |    1 | passwd-A | |name-10    |     234 |    1 | passwd-A | | name-13    |     237 |    1 | passwd-A | | name-16    |  
240 |    1 | passwd-A | | name-19    |     243 |    1 | passwd-A | | name-22    |     246 |    1 |passwd-A | | buyer-2    |     249 |    2 | passwd-A | +------------+---------+------+----------+ 9 rows in set(0.00 sec)mysql> select * from tb_seller_order; +----------------+---------------+----------+-------+--------+ |seller_user_id | buyer_user_id | order_id | price | STATUS | +----------------+---------------+----------+-------+--------+ |            225 |           248 |      201 |  1222 |   NULL | +----------------+---------------+----------+-------+--------+ 1 row in set (0.00 sec)mysql> select * from tb_order_detail; +----------------+-----------------+----------+----------+-------------+------+------------+ | seller_user_id | order_detail_id | order_id | goods_id | goods_name  | cnt  | unit_price| +----------------+-----------------+----------+----------+-------------+------+------------+ |            225 |             201 |
  201 |       11 | goods_name  |    1 |       1220 | |            225 |             202 |      201 |       11 |goods_name2 |    1 |          2 | +----------------+-----------------+----------+----------+-------------+------+------------

• 2 rows in set (0.00 sec)109.131数据为：mysql> select * from tb_user; +------------+---------+------+----------+ | login_name |user_id | TYPE | passwd   | +------------+---------+------+----------+ | name-2     |     226 |    1 | passwd-A| | name-5     |     229 |    1 | passwd-A | | name-8     |     232 |    1 | passwd-A | | name-11    |  
  235 |    1 | passwd-A | | name-14    |     238 |    1 | passwd-A | | name-17    |     241 |    1 |passwd-A | | name-20    |     244 |    1 | passwd-A | | name-23    |     247 |    1 | passwd-A | |buyer-3    |     250 |    2 | passwd-A | +------------+---------+------+----------+ 9 rows in set (0.00 sec)mysql> select * from tb_seller_order; +----------------+---------------+----------+-------+--------+ |seller_user_id | buyer_user_id | order_id | price | STATUS | +----------------+---------------+----------+-------+--------+ |            238 |           248 |      203 |  1222 |   NULL | +----------------+---------------+----------+-------+--------+ 1 row in set (0.00 sec)mysql> select * from tb_order_detail; +----------------+-----------------+----------+----------+-------------+------+------------+ | seller_user_id | order_detail_id | order_id | goods_id | goods_name  | cnt  | unit_price| +----------------+-----------------+----------+----------+-------------+------+------------+ |            238 |             203 |
  203 |       11 | goods_name  |    1 |       1220 | |            238 |             204 |      203 |       11 |goods_name2 |    1 |          2 | +----------------+-----------------+----------+----------+-------------+------+------------

• 2 rows in set (0.00 sec)

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