Mycat分库路由规则

一、Mycat分库路由分为连续路由和离散路由。

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1、连续路由:

(1)、常用的路由方式:auto-sharding-long、sharding-by-date、sharding-by-month

(2)、优点:扩容无需迁移数据;范围条件查询消耗资源少。

(3)、缺点:存在数据热点的可能性;并发访问能力受限于单一或少量的DataNode

2、离线路由:

(1)、常用的路由方式:sharding-by-intfile、sharding-by-murmur、mod-long(取模)、crc32slot(取模)

(2)、优点:并发访问能力增强。

(3)、缺点:数据扩容比较困难,涉及到数据迁移问题;数据库链接消耗资源多。


二、auto-sharding-long:

1、路由规则:

     

             userid

             rang-long-userid

     

 

        class="io.mycat.route.function.AutoPartitionByLong">

        autopartition-long-userid.txt

[root@host01 conf]# more autopartition-long-userid.txt

# range start-end ,data node index

# K=1000,M=10000.

0-1000=0

1001-2000=1

2001-3000=2

3001-4000=3

4001-5000=4

5001-6000=5

2、例子:

CREATE TABLE tb_user_detail_t (

  userid bigint not null primary key,

  name varchar(64) DEFAULT NULL,

  createtime datetime DEFAULT CURRENT_TIMESTAMP,

  moditytime datetime DEFAULT CURRENT_TIMESTAMP

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

写入数据

insert into tb_user_detail_t(userid,name) values(999,'name999');

insert into tb_user_detail_t(userid,name) values(1999,'name999');

insert into tb_user_detail_t(userid,name) values(2999,'name999');

insert into tb_user_detail_t(userid,name) values(3999,'name999');

insert into tb_user_detail_t(userid,name) values(4999,'name999');

insert into tb_user_detail_t(userid,name) values(5999,'name999');

三、sharding-by-date:

1、路由规则:

       createtime

       partbydate

    yyyy-MM-dd HH:mm:ss

    2016-01-01 00:00:00

    2

分片日期从2016-01-01开始,每2天一个分片。

2、例子:

CREATE TABLE `tb_user_partbydate` (

  `id` varchar(32) NOT NULL,

  `name` varchar(64) DEFAULT NULL,

  `createtime` varchar(10)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

insert into tb_user_partbydate (id,name,createtime) values('a0001','name1','2016-01-01 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0002','name1','2016-01-02 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0003','name1','2016-01-03 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0004','name1','2016-01-04 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0005','name1','2016-01-05 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0006','name1','2016-01-06 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0007','name1','2016-01-07 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0005','name1','2016-01-08 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0006','name1','2016-01-09 00:01:00');
insert into tb_user_partbydate (id,name,createtime) values('a0007','name1','2016-01-10 00:01:00');

四、sharding-by-month:

1、路由规则:

       

                createtime

                partbymonth

       

        class="io.mycat.route.function.PartitionByMonth">

        yyyy-MM-dd HH:mm:ss

        2015-01-01 00:00:00

dateFormat为日期格式,sBeginDate为开始日期。

2、例子:

CREATE TABLE ` tb_partbymonth ` (

  `id` varchar(32) NOT NULL,

  `name` varchar(64) DEFAULT NULL,

  `createtime` datetime DEFAULT CURRENT_TIMESTAMP

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

写入数据(注意这里不能使用now函数)

insert into tb_partbymonth(id,name,createtime) values('a0001','name1','2015-01-01 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0002','name1','2015-02-02 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0003','name1','2015-03-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0004','name1','2015-04-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0005','name1','2015-05-01 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0006','name1','2015-06-02 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0007','name1','2015-07-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0008','name1','2015-08-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0009','name1','2015-09-01 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0010','name1','2015-10-02 10:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0011','name1','2015-11-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0012','name1','2015-12-01 00:00:00');

insert into tb_partbymonth(id,name,createtime) values('a0013','name1','2016-01-01 00:00:00');

五、sharding-by-intfile(枚举):

1、路由规则:

       

                provcode

                hash-int-provcode

       

 

        class="io.mycat.route.function.PartitionByFileMap">

        partition-hash-int-provcode.txt

        0

type=0代表×××

type=1代表字符串类型

[root@host01 conf]# more partition-hash-int-provcode.txt

1=0

2=1

3=2

4=3

5=4

6=5

7=0

8=1

9=2

10=3

11=4

12=5

DEFAULT_NODE=0 ##找不到省份匹配的情况下,默认放到数据库1

这里是6个库,序号0-5,将不同的省份映射到对应的库。所有的省份和库哦对应关系都要枚举出来。

2、例子:

CREATE TABLE `tb_user_t` (

  id bigint auto_increment not null primary key,

  `name` varchar(64) DEFAULT NULL,

   provcode int ,

  `createtime` datetime DEFAULT CURRENT_TIMESTAMP,

  `moditytime` datetime DEFAULT CURRENT_TIMESTAMP

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

发现分库情况下定义自动增长的id不管用,因为每个库都有自己的自增长id,通过mycat查询的话会有重复的id.

如下:

MySQL> select * from tb_user_t order by id;

+----+----------+----------+---------------------+---------------------+

| id | name     | provcode | createtime          | moditytime          |

+----+----------+----------+---------------------+---------------------+

|  1 | name0005 |        5 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  1 | name0001 |        1 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  1 | name0004 |        4 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  1 | name0002 |        2 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  1 | name0003 |        3 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  1 | name0006 |        6 | 2017-08-09 10:54:44 | 2017-08-09 10:54:44 |

|  2 | name0011 |       11 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  2 | name0007 |        7 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  2 | name0010 |       10 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  2 | name0008 |        8 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  2 | name0009 |        9 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  2 | name0012 |       12 | 2017-08-09 10:54:53 | 2017-08-09 10:54:53 |

|  3 | name0013 |       13 | 2017-08-09 11:12:17 | 2017-08-09 11:12:17 |

+----+----------+----------+---------------------+---------------------+

六、sharding-by-murmur:

murmur算法是将字段进行hash后分发到不同的数据库,字段类型支持int和varchar.

1、路由规则:

       

                userid

                murmur

       

 

class="io.mycat.route.function.PartitionByMurmurHash">

0

6

160

2、例子:

CREATE TABLE `tb_user_murmur_string_t` (

  `userid` varchar(32) NOT NULL,

  `name` varchar(64) DEFAULT NULL,

  `createtime` datetime DEFAULT CURRENT_TIMESTAMP,

  `moditytime` datetime DEFAULT CURRENT_TIMESTAMP,

  PRIMARY KEY (`userid`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

 

写入数据

insert into tb_user_murmur_string_t(userid,name) values('user002','name002');

insert into tb_user_murmur_string_t(userid,name) values('user003','name003');

insert into tb_user_murmur_string_t(userid,name) values('user004','name004');

insert into tb_user_murmur_string_t(userid,name) values('user005','name005');

insert into tb_user_murmur_string_t(userid,name) values('user006','name006');

insert into tb_user_murmur_string_t(userid,name) values('user007','name007');

insert into tb_user_murmur_string_t(userid,name) values('user008','name008');

insert into tb_user_murmur_string_t(userid,name) values('user009','name009');

insert into tb_user_murmur_string_t(userid,name) values('user010','name010');

七、crc32slot:

crs32算法,分库字段类型支撑int和varchar.

1、路由规则:

       

           id

           crc32slot

       

 

 

        6

 

count=6指定需要分库的个数.

2、例子:

CREATE TABLE `tb_user_crc32slot_t` (

  `id` varchar(32) NOT NULL,

  `name` varchar(64) DEFAULT NULL,

  `createtime` datetime DEFAULT CURRENT_TIMESTAMP,

  `moditytime` datetime DEFAULT CURRENT_TIMESTAMP

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 

写入数据:

insert into tb_user_crc32slot_t(id,name) values('a0002','name1');

insert into tb_user_crc32slot_t(id,name) values('a0003','name1');

insert into tb_user_crc32slot_t(id,name) values('a0004','name1');

insert into tb_user_crc32slot_t(id,name) values('a0005','name1');

insert into tb_user_crc32slot_t(id,name) values('a0006','name1');

insert into tb_user_crc32slot_t(id,name) values('a0007','name1');

insert into tb_user_crc32slot_t(id,name) values('a0008','name1');

insert into tb_user_crc32slot_t(id,name) values('a0009','name1');

insert into tb_user_crc32slot_t(id,name) values('a0010','name1');

insert into tb_user_crc32slot_t(id,name) values('a0011','name1');

insert into tb_user_crc32slot_t(id,name) values('a0012','name1');

insert into tb_user_crc32slot_t(id,name) values('a0013','name1');

insert into tb_user_crc32slot_t(id,name) values('a0014','name1');

insert into tb_user_crc32slot_t(id,name) values('a0015','name1');


八、mod-long:

1、路由规则:对十进制数进行按照节点取模。

       

           id

           mod-long

       

 

 

        3

         

 

九、mycat分库规则E/R规则 :

1、路由规则:

E/R规则通过childTable设定之后,父子表相同的Id会落在相同的库,这样的避免关联的时候跨库进行关联.

joinKey="order_id" 是子表的order_id字段

parentKey="id"     是父表的id字段

即子表通过order_id字段跟父表的id字段进行关联

Mycat分库路由规则

2、例子

(2.1)、创建表语句:

create table orders

(

  idint not null,

  order_name varchar(64),

  createtime datetime DEFAULT CURRENT_TIMESTAMP,

  moditytime datetime DEFAULT CURRENT_TIMESTAMP,

  PRIMARY KEY (id)

);

create table orders_cargo

(

  order_idint not null,

  cargo_name varchar(64),

  createtime datetime DEFAULT CURRENT_TIMESTAMP,

  moditytime datetime DEFAULT CURRENT_TIMESTAMP,

 PRIMARY KEY (order_id)  

);

(2.2)、客户Custermer和订单Order

    每个客户和每个客户的订单最好在同一个库中。

    Mycat分库路由规则

3、如果把父表最为全局表也能解决join的效率问题。

Mycat分库路由规则


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