Mycat实战之配置EP分片

ER分片介绍

   以mycat逻辑库里面自带的例子,例如客户（CUSTOMER）跟订单（orders）以及订单条目（orders_item),订单条目依
   赖订单表，订单表依赖客户，这样客户与订单以及订单条目之间存在依赖关系，这类似业务的切分可以抽象出合适的切分
   规则，比如根据用户ID切分,其它相关的表都依赖于用户ID，再或者根据订单ID进行切分，总之部分业务总会可以抽象出
   父子关系的表。这类表适用于ER分片表，子表的记录与所关联的父表记录存放在同一个数据分片上，避免数据Join跨库操
   作，以order与order_item例子为例和customer与order，schema.xml中定义合适的分片配置,order,order_item根
   据id迕行数据切分，保证相同id的数据分到同一个分片上，在进行数据插入操作时，Mycat会获取order所在的分片，然
   后将order_item也插入到order所在的分片。同理order与customer也是这样关系。

Tables	主键	对应的父表	关联关系
customer	id
orders	id	customer	orders.customer_id=customer.id
order_items	id	orders	order_items.order_id=orders.id
customer_addr	id	customer	customer_addr.customer_id= customer.id

1 修改 scehma.xml 添加 ER分片对应的父子表

#customer 采用rule是sharding-by-intfile，是枚举类型，类似range，可以看成是range特例情况.

[root@localhost conf]# vi schema.xml

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

		<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">
				<table name="travelrecord" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />
				<table name="T_VOTE" dataNode="dn1,dn2,dn3" rule="sharding-by-murmur" />
				<table name="customer" primaryKey="ID" dataNode="dn1,dn2"
						rule="sharding-by-intfile">
						<childTable name="orders" primaryKey="ID" joinKey="customer_id"
								parentKey="id">
								<childTable name="order_items" joinKey="order_id"
										parentKey="id" />
						</childTable>
						<childTable name="customer_addr" primaryKey="ID" joinKey="customer_id"
								parentKey="id" />
				</table>
		</schema>
		<dataNode name="dn1" dataHost="192.168.2.130" database="db1" />
		<dataNode name="dn2" dataHost="192.168.2.130" database="db2" />
		<dataNode name="dn3" dataHost="192.168.2.130" database="db3" />
		<dataHost name="192.168.2.130" maxCon="1000" minCon="10" balance="0"
				writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
				<heartbeat>select user()</heartbeat>
				<writeHost host="hostM1" url="192.168.2.130:3306" user="root"
						password="root123">
				</writeHost>
		</dataHost>
</mycat:schema>

2 修改 rule.xml

   #修改默认规则columns里面对应sharding_id变成id
    <tableRule name="sharding-by-intfile">
            <rule>
                    <columns>id</columns>
                    <algorithm>hash-int</algorithm>
            </rule>
    </tableRule>

    <function name="hash-int"
            class="org.opencloudb.route.function.PartitionByFileMap">
            <property name="mapFile">partition-hash-int.txt</property>
    </function>

 #修改func 对应的文本:定义2个值对应datanode
 [root@localhost conf]# vi partition-hash-int.txt
 10000=0
 10010=1

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

3 在逻辑库中创建需要表

注释:创建customer和customer_addr表演示ER分片.
[root@localhost bin]# mysql -h 192.168.2.130  -P8066  -u test -ptest
Warning: Using a password on the command line interfa ce can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 5.5.8-mycat-1.5.1-RELEASE-20161130213509 MyCat Server (OpenCloundDB)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>
mysql>
mysql> show databases;
+----------+
| DATABASE |
+----------+
| TESTDB   |
+----------+
1 row in set (0.00 sec)

mysql> use TESTDB
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+------------------+
| Tables in TESTDB |
+------------------+
| customer         |
| customer_addr    |
| orders           |
| order_items      |
| travelrecord     |
| t_vote           |
+------------------+
6 rows in set (0.00 sec)

mysql> create table customer(id int not null,customer_id int not null,datanode varchar(10),primary key(id));
Query OK, 0 rows affected (0.09 sec)

mysql>  create table customer_addr(id int not null,customer_id int not null,customer_addr varchar(200),datanode varchar(10),primary key(id));
Query OK, 0 rows affected (0.04 sec)

插入数据到customer和customer_addr表

a:插入数据到customer

mysql> insert into customer(id,customer_id,datanode) values(10000,1,database());
Query OK, 1 row affected (0.07 sec)

对应的日志



可以看到写入到db1

b:插入数据到 customer_addr

mysql> insert into customer_addr (id, customer_id, customer_addr, datanode)
       values (10000, 10000, 'shanghai', DATABASE())
Query OK, 1 row affected (0.11 sec)

对应的日志

c:继续插入数据到dn2

mysql> insert into customer(id,customer_id,datanode) values(10010,2,database());
Query OK, 1 row affected (0.01 sec)

mysql> insert into customer_addr(id,customer_id,customer_addr,datanode) values
       (10010,10010,'chengdu',database());
Query OK, 1 row affected (0.11 sec)

4 验证ER分片

#获取全部数据
mysql> explain select customer.id,customer.customer_id,customer.datanode,
                      customer_addr.customer_addr
               from customer,customer_addr
			   where customer.id=customer_addr.customer_id;
+-----------+-----------------------------------------------------------+
| DATA_NODE | SQL                                                       |
+-----------+-----------------------------------------------------------+
| dn1       |select customer.id,customer.customer_id,customer.datanode, |
|			|       customer_addr.customer_addr                         |
|			|from customer,customer_addr                                |
|			|where customer.id=customer_addr.customer_id;	 			|
|			|															|
| dn2       |select customer.id,customer.customer_id,customer.datanode,	|
|			|       customer_addr.customer_addr 						|
|			|from customer,customer_addr 								|
|			|where customer.id=customer_addr.customer_id;	 			|
+-----------+-----------------------------------------------------------+

对应的日志

由上可知走的是全部路由

#获取单个分片上的数据
mysql> explain select customer.id,customer.customer_id,customer.datanode,
                      customer_addr.customer_addr
				from customer,customer_addr
				where customer.id=customer_addr.customer_id and customer.id=10000;
+-----------+--------------------------------------------------------------------+
| DATA_NODE | SQL                                                                |
+-----------+--------------------------------------------------------------------+
| dn1       | select customer.id,customer.customer_id,customer.datanode,		 |
|           |        customer_addr.customer_addr								 |
|			| from customer,customer_addr										 |
|			| where customer.id=customer_addr.customer_id and customer.id=10000  |
+-----------+--------------------------------------------------------------------+
1 row in set (0.00 sec)

由上可知路由到了dn1上