Mycat分片规则是怎么样的,针对这个问题,这篇文章详细介绍了相对应的分析和解答,希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。

1.sharding-by-intfilehash分片

表对应的分片规则


查看rule.xml查看对应的关系

<tableRule name="sharding-by-intfile">

<rule>

<columns>sharding_id</columns> 根据该字段分片

<algorithm>hash-int</algorithm> 分片的方法

</rule>

</tableRule>


查看rule.xml对应的方法

<function name="hash-int"

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

<property name="mapFile">partition-hash-int.txt</property> ---对应的文件

<property name="defaultNode">1</property>

</function>


查看文件

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

10000=0 ####sharding_id为10000发到1节点

10010=1 ####sharding_id为10010发到2节点

DEFAULT_NODE=1 ###其它插到2节点




实验
mysql> create table employee (id int not null primary key,name varchar(100),sharding_id int not null);
Query OK, 0 rows affected (0.02 sec)

mysql> insert into employee(id,name,sharding_id) values(2,'leader us',10000);
Query OK, 1 row affected (0.01 sec)


mysql> insert into employee(id,name,sharding_id) values(4,'leader us',10000);
Query OK, 1 row affected (0.00 sec)


mysql> insert into employee(id,name,sharding_id) values(3,'leader us',100003); -----其它插到2节点



mysql> insert into employee(id,name,sharding_id) values(4,'leader us',10010);
Query OK, 1 row affected (0.01 sec)


mysql> insert into employee(id,name,sharding_id) values(5,'leader us',10010);
Query OK, 1 row affected (0.03 sec)


2.auto-sharding-long范围分片

分片表如下:

<table name="travelrecord" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />

查看rule.xml对应的关系

<tableRule name="auto-sharding-long">

<rule>

<columns>id</columns>

<algorithm>rang-long</algorithm>

</rule>

</tableRule>

对应的方法

<function name="rang-long"

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

<property name="mapFile">autopartition-long.txt</property>

</function>

对应的文件:

# range start-end ,data node index

# K=1000,M=10000.

0-500M=0 #####范围0-500M插到第一个节点

500M-1000M=1 #####范围500m-1000M插到第2个节点

1000M-1500M=2 。。。类推


3.mod-log取模分片

<table name="tt2" primaryKey="id" autoIncrement="true" dataNode="dn1,dn2,dn3" rule="mod-long" />



fun:



<function name="mod-long" class="io.mycat.route.function.PartitionByMod">

<!-- how many data nodes -->

<property name="count">3</property>

</function>

<tableRule name="mod-long">

<rule>

<columns>id</columns>

<algorithm>mod-long</algorithm>

</rule>

</tableRule>


4. sharding-by-month按月分片

tab:

<table name="month_tab" primaryKey="id" autoIncrement="true" dataNode="dn1,dn2,dn3" rule="sharding-by-month" />



rule:

<tableRule name="sharding-by-month">

<rule>

<columns>create_time</columns>

<algorithm>partbymonth</algorithm>

</rule>

</tableRule>



<function name="partbymonth"

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

<property name="dateFormat">yyyy-MM-dd</property>

<property name="sBeginDate">2015-01-01</property> ##开始时间

</function>


测试:
mysql> insert into month_tab(id,name,sharding_id,create_time) values (1,'1',1,'2015-01-01');
Query OK, 1 row affected (0.43 sec)

mysql> insert into month_tab(id,name,sharding_id,create_time) values (2,'2',2,'2015-02-02');
Query OK, 1 row affected (0.01 sec)

mysql> insert into month_tab(id,name,sharding_id,create_time) values (3,'3',3,'2015-03-03');
Query OK, 1 row affected (0.49 sec)

mysql> insert into month_tab(id,name,sharding_id,create_time) values (4,'4',4,'2015-04-04'); ###按月分片,只有三个节点,只能插到1,2,3月份的,4月份就开始报错了
ERROR 1064 (HY000): Can't find a valid data node for specified node index :MONTH_TAB -> CREATE_TIME -> 2015-04-04 -> Index : 3

5 sharding-by-day按日分片(1.6默认文件都没写,自己配置的)

tab:

<table name="day_tab" primaryKey="ID" dataNode="dn1,dn2,dn3" rule="sharding-by-day"/>


rule:

<tableRule name="sharding-by-day">

<rule>

<columns>create_time</columns>

<algorithm>partbyday</algorithm>

</rule>

</tableRule>



<function name="partbyday"

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

<property name="dateFormat">yyyy-MM-dd</property>

<property name="sBeginDate">2015-01-01</property> ###起始日期

<property name="sPartionDay">3</property> ###多少天后开始分片

</function>

测试:

插了前9天,分到三个分片

mysql> select * from day_tab;
+----+------+-------------+---------------------+
| id | name | sharding_id | create_time |
+----+------+-------------+---------------------+
| 7 | 1 | 1 | 2015-01-08 00:00:00 |
| 8 | 1 | 1 | 2015-01-09 00:00:00 |
| 13 | 1 | 1 | 2015-01-07 00:00:00 |
| 7 | 1 | 1 | 2015-01-01 00:00:00 |
| 8 | 1 | 1 | 2015-01-02 00:00:00 |
| 9 | 1 | 1 | 2015-01-03 00:00:00 |
| 10 | 1 | 1 | 2015-01-04 00:00:00 |
| 11 | 1 | 1 | 2015-01-05 00:00:00 |
| 12 | 1 | 1 | 2015-01-06 00:00:00 |
+----+------+-------------+---------------------+
9 rows in set (0.01 sec)

mysql> insert into day_tab(id,name,sharding_id,create_time) values (17,'1',1,'2015-01-10'),(18,'1',1,'2015-01-11'); ###插第10天的,开始报错
ERROR 1064 (HY000): Index: 3, Size: 3

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