MySQL复合分区_MySQL

在MySQL 5.6版本中，只支持RANGE和LIST的子分区，且子分区的类型只能为HASH和KEY。

譬如：

CREATE TABLE ts (id INT, purchased DATE)
 PARTITION BY RANGE( YEAR(purchased) )
 SUBPARTITION BY HASH( TO_DAYS(purchased) )
 SUBPARTITIONS 2 (
 PARTITION p0 VALUES LESS THAN (1990),
 PARTITION p1 VALUES LESS THAN (2000),
 PARTITION p2 VALUES LESS THAN MAXVALUE
 );

上述创建语句中，最外层是RANGE分区，分为3个区，里面是HASH子分区，分为2个区，这样，该表一共分了3*2=6个分区。

当然，也可以用SUBPARTITION语句来显示定义子分区。

CREATE TABLE ts (id INT, purchased DATE)
 PARTITION BY RANGE( YEAR(purchased) )
 SUBPARTITION BY HASH( TO_DAYS(purchased) ) (
 PARTITION p0 VALUES LESS THAN (1990) (
 SUBPARTITION s0,
 SUBPARTITION s1
 ),
 PARTITION p1 VALUES LESS THAN (2000) (
 SUBPARTITION s2,
 SUBPARTITION s3
 ),
 PARTITION p2 VALUES LESS THAN MAXVALUE (
 SUBPARTITION s4,
 SUBPARTITION s5
 )
 );

注意：

1> 如果你在分区中使用了SUBPARTITION语句，则每个分区中都必须定义，且每个分区中子分区的数量必须保持一致。譬如以下两种用法就会报错：

CREATE TABLE ts (id INT, purchased DATE)
 PARTITION BY RANGE( YEAR(purchased) )
 SUBPARTITION BY HASH( TO_DAYS(purchased) ) (
 PARTITION p0 VALUES LESS THAN (1990) (
 SUBPARTITION s0,
 SUBPARTITION s1
 ),
 PARTITION p1 VALUES LESS THAN (2000) (
 SUBPARTITION s2
 ),
 PARTITION p2 VALUES LESS THAN MAXVALUE (
 SUBPARTITION s3,
 SUBPARTITION s4
 )
 );


CREATE TABLE ts (id INT, purchased DATE)
 PARTITION BY RANGE( YEAR(purchased) )
 SUBPARTITION BY HASH( TO_DAYS(purchased) ) (
 PARTITION p0 VALUES LESS THAN (1990) (
 SUBPARTITION s0,
 SUBPARTITION s1
 ),
 PARTITION p1 VALUES LESS THAN (2000),
 PARTITION p2 VALUES LESS THAN MAXVALUE (
 SUBPARTITION s2,
 SUBPARTITION s3
 )
 );

2> 在SUBPARTITION语句中，可指定该分区的物理位置。譬如：

CREATE TABLE ts (id INT, purchased DATE)
 PARTITION BY RANGE(YEAR(purchased))
 SUBPARTITION BY HASH( TO_DAYS(purchased) ) (
 PARTITION p0 VALUES LESS THAN (1990) (
 SUBPARTITION s0a
 DATA DIRECTORY = '/disk0'
 INDEX DIRECTORY = '/disk1',
 SUBPARTITION s0b
 DATA DIRECTORY = '/disk2'
 INDEX DIRECTORY = '/disk3'
 ),
 PARTITION p1 VALUES LESS THAN (2000) (
 SUBPARTITION s1a
 DATA DIRECTORY = '/disk4/data'
 INDEX DIRECTORY = '/disk4/idx',
 SUBPARTITION s1b
 DATA DIRECTORY = '/disk5/data'
 INDEX DIRECTORY = '/disk5/idx'
 ),
 PARTITION p2 VALUES LESS THAN MAXVALUE (
 SUBPARTITION s2a,
 SUBPARTITION s2b
 )
 );

以上这个创建语句，将不同的分区分布到不同的物理路径下，无疑会极大的分散IO，这一点还是蛮吸引人的。

可惜，在本机测试过程中，报“ERROR 1030 (HY000): Got error -1 from storage engine”错误，具体原因还不太清楚，怀疑是MySQL的bug。