Mycat之——枚举分片

转载请注明出处：http://blog.csdn.net/l1028386804/article/details/77096144

一、简单描述

今天，我们就一起来看下Mycat中的枚举分片，所谓的枚举分片，就是通过在配置文件中配置可能的枚举id，自己配置分片，本规则适用于特定的场景，比如有些业务需要按照省份或区县来做保存，而全国省份区县固定的，具体使用场景可根据自己具体的业务场景确定。

二、实现枚举分片

1、配置rule.xml

在rule.xml添加如下配置：

<!--     mapFile标识配置文件名称    type默认值为0（0表示Integer，非零表示String）    默认节点的作用：枚举分片时，如果碰到不识别的枚举值，就让它路由到默认节点    --> <function name="hash-int-customer" class="org.opencloudb.route.function.PartitionByFileMap">    <property name="mapFile">partition-hash-int.txt</property>     <property name="defaultNode">0</property>     <property name="type">0</property></function><tableRule name="tr-hash-int-customer">     <rule>         <columns>province</columns>         <algorithm>hash-int-customer</algorithm>    </rule></tableRule>

2、创建partition-hash-int.txt文件

内容如下：

10000=0 10010=1

3、配置schema.xml

<?xml version="1.0"?><!DOCTYPE mycat:schema SYSTEM "schema.dtd"><mycat:schema xmlns:mycat="http://org.opencloudb/" ><schema name="lyzdb" checkSQLschema="false" sqlMaxLimit="100"><!-- global table is auto cloned to all defined data nodes ,so can join with any table whose sharding node is in the same data node --><table name="t_order" primaryKey="id" dataNode="dn1,dn2" rule="tr-hash-int-customer"/></schema><!-- <dataNode name="dn1$0-743" dataHost="localhost1" database="db$0-743" /> --><dataNode name="dn1" dataHost="localhost1" database="db1" /><dataNode name="dn2" dataHost="localhost1" database="db2" /><!--<dataNode name="dn4" dataHost="sequoiadb1" database="SAMPLE" /> <dataNode name="jdbc_dn1" dataHost="jdbchost" database="db1" /> <dataNodename="jdbc_dn2" dataHost="jdbchost" database="db2" /> <dataNode name="jdbc_dn3" dataHost="jdbchost" database="db3" /> --><dataHost name="localhost1" 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="hostM1" url="192.168.209.137:3306" user="root" password="root"></writeHost><!--<writeHost host="hostS1" url="localhost:3316" user="root"--><!--password="123456" />--><!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> --></dataHost></mycat:schema>

至此，Mycat的配置工作就完成了，下面我们就一起来测试下Mycat的枚举分片功能。

三、测试

1、建表并且录入数据

mysql> explain CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME);+-----------+--------------------------------------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                                                |+-----------+--------------------------------------------------------------------------------------------------------------------+| dn1       | CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME) || dn2       | CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME) |+-----------+--------------------------------------------------------------------------------------------------------------------+2 rows in set (0.09 sec)mysql>mysql> CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME);Query OK, 0 rows affected (0.19 sec)mysql> explain INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(1,10000,'beijing_10001_10000',NOW());+-----------+----------------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                          |+-----------+----------------------------------------------------------------------------------------------+| dn1       | INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(1,10000,'beijing_10001_10000',NOW()) |+-----------+----------------------------------------------------------------------------------------------+1 row in set (0.07 sec)mysql> INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(1,10000,'beijing_10001_10000',NOW());Query OK, 1 row affected (0.11 sec)mysql> explain INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(2,10010,'tianjin_10010',NOW());+-----------+----------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                    |+-----------+----------------------------------------------------------------------------------------+| dn2       | INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(2,10010,'tianjin_10010',NOW()) |+-----------+----------------------------------------------------------------------------------------+1 row in set (0.00 sec)mysql> INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(2,10010,'tianjin_10010',NOW());Query OK, 1 row affected (0.04 sec)

Mycat日志如下：

NCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME), route={   1 -> dn1{CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME)}   2 -> dn2{CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,PROVINCE INT,SN VARCHAR(64),CREATE_TIME DATETIME)}} rrs 08/10 13:38:09.330  DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:113) -ServerConnection [id=1, schema=lyzdb, host=192.168.209.1, user=lyz,txIsolation=3, autocommit=true, schema=lyzdb]INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(1,10000,'beijing_10001_10000',NOW()), route={   1 -> dn1{INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(1,10000,'beijing_10001_10000',NOW())}} rrs 08/10 13:39:45.878  DEBUG [$_NIOREACTOR-0-RW] (NonBlockingSession.java:113) -ServerConnection [id=1, schema=lyzdb, host=192.168.209.1, user=lyz,txIsolation=3, autocommit=true, schema=lyzdb]INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(2,10010,'tianjin_10010',NOW()), route={   1 -> dn2{INSERT INTO t_order (ID,PROVINCE,SN,CREATE_TIME) VALUES(2,10010,'tianjin_10010',NOW())}} rrs 

由此可见，创建表的时候，Mycat是将SQL路由到所有的数据节点；录入数据的时候，是根据分片字段将数据路由到指定的数据分片节点；

2、按照分片字段查询

mysql> explain select * from t_order where PROVINCE=10000;+-----------+--------------------------------------------------------+| DATA_NODE | SQL                                                    |+-----------+--------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE PROVINCE = 10000 LIMIT 100 |+-----------+--------------------------------------------------------+1 row in set (0.40 sec)

Mycat日志如下：

08/10 13:42:02.586  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:76) -SQLRouteCache  miss cache ,key:lyzdb select * from t_order where PROVINCE=1000008/10 13:42:02.987  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59) -SQLRouteCache add cache ,key:lyzdb select * from t_order where PROVINCE=10000 value:select * from t_order where PROVINCE=10000, route={   1 -> dn1{SELECT *FROM t_orderWHERE PROVINCE = 10000LIMIT 100}}

由此可见，执行简单的查询，如果指定分片字段ID字段，则走分片查询单个分片节点

3、按照分片字段范围查询

mysql> explain select * from t_order where PROVINCE >= 10000;+-----------+---------------------------------------------------------+| DATA_NODE | SQL                                                     |+-----------+---------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE PROVINCE >= 10000 LIMIT 100 || dn2       | SELECT * FROM t_order WHERE PROVINCE >= 10000 LIMIT 100 |+-----------+---------------------------------------------------------+2 rows in set (0.00 sec)

Mycat日志如下：

08/10 13:43:07.238  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59) -SQLRouteCache add cache ,key:lyzdb select * from t_order where PROVINCE >= 10000 value:select * from t_order where PROVINCE >= 10000, route={   1 -> dn1{SELECT *FROM t_orderWHERE PROVINCE >= 10000LIMIT 100}   2 -> dn2{SELECT *FROM t_orderWHERE PROVINCE >= 10000LIMIT 100}}

由此可见，如果分片字段范围的查询，则走所有节点去检索，哪怕只有一条数据在一个分片上，route路由也是走所有的分片进行检索查询

4、按照非分片字段查询

mysql> explain select * from t_order where sn = 'tianjin_10010';+-----------+------------------------------------------------------------+| DATA_NODE | SQL                                                        |+-----------+------------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE sn = 'tianjin_10010' LIMIT 100 || dn2       | SELECT * FROM t_order WHERE sn = 'tianjin_10010' LIMIT 100 |+-----------+------------------------------------------------------------+2 rows in set (0.00 sec)

Mycat日志如下：

08/10 13:45:01.416  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59) -SQLRouteCache add cache ,key:lyzdb select * from t_order where sn = 'tianjin_10010' value:select * from t_order where sn = 'tianjin_10010', route={   1 -> dn1{SELECT *FROM t_orderWHERE sn = 'tianjin_10010'LIMIT 100}   2 -> dn2{SELECT *FROM t_orderWHERE sn = 'tianjin_10010'LIMIT 100}}

由此可见，如果不走分片字段的查询，即使是单个数据，也要route路由所有的分片，走所有的分片进行查询