Mycat之——程序指定分区分片

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转载请注明出处：http://blog.csdn.net/l1028386804/article/details/77140429

一、简单描述

程序指定分区分片，就是说程序在运行的运行根据规则自动指定数据的分片结果，具体规则如下：

此规则是在运行阶段有应用自主决定路由到那个分片。
此方法为直接根据字符子串（必须是数字）计算分区号（由应用传递参数，显式指定分区号）。

二、实现数据分片

1、配置rule.xml

在rule.xml中添加如下配置：

<!--例如id=0-100000020在此配置中代表根据id中从startIndex=0，开始，截取siz=1位数字即0，0就是获取的分区，如果没传默认分配到defaultPartition--><function name="sharding-by-substring-customer" class="org.opencloudb.route.function.PartitionDirectBySubString">    <property name="startIndex">0</property>    <property name="size">1</property>    <property name="partitionCount">8</property>    <property name="defaultPartition">0</property></function><tableRule name="tr-sharding-substr-customer">     <rule>         <columns>CODE</columns>          <algorithm>sharding-by-substring-customer</algorithm>    </rule></tableRule>

2、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-sharding-substr-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，下面我们一起来测试下Mycat的路由结果。

三、测试数据分片

1、创建数据表

mysql> explain  CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME);+-----------+------------------------------------------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                                                    |+-----------+------------------------------------------------------------------------------------------------------------------------+| dn1       | CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME) || dn2       | CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME) |+-----------+------------------------------------------------------------------------------------------------------------------------+2 rows in set (0.00 sec)mysql>  CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME);Query OK, 0 rows affected (0.38 sec)

查看Mycat日志如下：

 08/13 09:49:52.185  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]CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME), route={   1 -> dn1{CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME)}   2 -> dn2{CREATE TABLE t_order (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,CODE VARCHAR(64),SN VARCHAR(64),CREATE_TIME DATETIME)}} rrs

由此可见，当创建数据表时，Mycat会将SQL路由到所有的数据分片。

2、录入数据

mysql> explain INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW());+-----------+-------------------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                             |+-----------+-------------------------------------------------------------------------------------------------+| dn1       | INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW()) |+-----------+-------------------------------------------------------------------------------------------------+1 row in set (0.12 sec)mysql> INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW());Query OK, 1 row affected (0.05 sec)mysql> explain INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW());+-----------+-------------------------------------------------------------------------------------------------+| DATA_NODE | SQL                                                                                             |+-----------+-------------------------------------------------------------------------------------------------+| dn2       | INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW()) |+-----------+-------------------------------------------------------------------------------------------------+1 row in set (0.00 sec)mysql> INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW());Query OK, 1 row affected (0.01 sec)

Mycat日志日下：

08/13 09:52:18.358  DEBUG [$_NIOREACTOR-0-RW] (ServerQueryHandler.java:56) -ServerConnection [id=1, schema=lyzdb, host=192.168.209.1, user=lyz,txIsolation=3, autocommit=true, schema=lyzdb]INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW())08/13 09:52:18.359  DEBUG [$_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,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW()), route={   1 -> dn1{INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(1,'0-10000020','beijing_13-10000010',NOW())}} rrs 08/13 09:52:59.379  DEBUG [$_NIOREACTOR-0-RW] (ServerQueryHandler.java:56) -ServerConnection [id=1, schema=lyzdb, host=192.168.209.1, user=lyz,txIsolation=3, autocommit=true, schema=lyzdb]INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW())08/13 09:52:59.380  DEBUG [$_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,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW()), route={   1 -> dn2{INSERT INTO t_order (ID,CODE,SN,CREATE_TIME) VALUES(2,'1-10000030','tianjin_14-10000020',NOW())}} rrs

由此可见，录入数据时，Mycat会根据路由规则，将SQL路由到指定的数据分片

3、指定数据分片字段查询

mysql> explain select * from t_order where code = '0-10000020';+-----------+-----------------------------------------------------------+| DATA_NODE | SQL                                                       |+-----------+-----------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE code = '0-10000020' LIMIT 100 |+-----------+-----------------------------------------------------------+1 row in set (0.16 sec)mysql> select * from t_order where code = '0-10000020';+----+------------+---------------------+---------------------+| ID | CODE       | SN                  | CREATE_TIME         |+----+------------+---------------------+---------------------+|  1 | 0-10000020 | beijing_13-10000010 | 2017-08-13 09:52:18 |+----+------------+---------------------+---------------------+1 row in set (0.01 sec)

Mycat日志如下：

08/13 09:54:23.917  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59) -SQLRouteCache add cache ,key:lyzdbselect * from t_order where code = '0-10000020' value:select * from t_order where code = '0-10000020', route={   1 -> dn1{SELECT *FROM t_orderWHERE code = '0-10000020'LIMIT 100}}

由此可见，执行简单的查询，如果指定分片字段，则走分片查询单个分片节点。

4、按照分片字段范围查询

mysql> explain select * from t_order  where CODE like '0-1%';+-----------+--------------------------------------------------------+| DATA_NODE | SQL                                                    |+-----------+--------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE CODE LIKE '0-1%' LIMIT 100 || dn2       | SELECT * FROM t_order WHERE CODE LIKE '0-1%' LIMIT 100 |+-----------+--------------------------------------------------------+2 rows in set (0.00 sec)mysql> select * from t_order  where CODE like '0-1%';+----+------------+---------------------+---------------------+| ID | CODE       | SN                  | CREATE_TIME         |+----+------------+---------------------+---------------------+|  1 | 0-10000020 | beijing_13-10000010 | 2017-08-13 09:52:18 |+----+------------+---------------------+---------------------+1 row in set (0.01 sec)

Mycat日志如下：

08/13 09:55:48.742  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]select * from t_order  where CODE like '0-1%', route={   1 -> dn1{SELECT *FROM t_orderWHERE CODE LIKE '0-1%'LIMIT 100}   2 -> dn2{SELECT *FROM t_orderWHERE CODE LIKE '0-1%'LIMIT 100}} rrs

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。

5、按照非分片字段查询

mysql> explain select * from t_order  where SN='beijing_13-10000010';+-----------+------------------------------------------------------------------+| DATA_NODE | SQL                                                              |+-----------+------------------------------------------------------------------+| dn1       | SELECT * FROM t_order WHERE SN = 'beijing_13-10000010' LIMIT 100 || dn2       | SELECT * FROM t_order WHERE SN = 'beijing_13-10000010' LIMIT 100 |+-----------+------------------------------------------------------------------+2 rows in set (0.00 sec)mysql>mysql> select * from t_order  where SN='beijing_13-10000010';+----+------------+---------------------+---------------------+| ID | CODE       | SN                  | CREATE_TIME         |+----+------------+---------------------+---------------------+|  1 | 0-10000020 | beijing_13-10000010 | 2017-08-13 09:52:18 |+----+------------+---------------------+---------------------+1 row in set (0.01 sec)

Mycat日志如下：

08/13 09:56:53.947  DEBUG [$_NIOREACTOR-0-RW] (EnchachePool.java:59) -SQLRouteCache add cache ,key:lyzdb select * from t_order  where SN='beijing_13-10000010' value:select * from t_order  where SN='beijing_13-10000010', route={   1 -> dn1{SELECT *FROM t_orderWHERE SN = 'beijing_13-10000010'LIMIT 100}   2 -> dn2{SELECT *FROM t_orderWHERE SN = 'beijing_13-10000010'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。

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