MySQL水平分区表实际操作总结

转载自：http://shuailan.iteye.com/blog/1056247

本文总结个这段时间研究MySQL水平分区表总结,列举分区表的相关操作.

在网上看了很多文章,都太过于概念,注意集中在介绍分区表的优点,而不注重时间操作,跟大学教授论文似的,唯一由于的一片文章和大家分享一下吧http://fanqiang.chinaunix.net/db/mysql/2006-05-08/4135.shtml

MySQL分区表操作代码 (本案例按月分区):
1. 创建分区表

Sql代码


CREATE TABLE `表名` (
`EQUIPMENTID` char(17) NOT NULL,
`ATTRIBUTEID` char(4) NOT NULL,
`VALUE` varchar(20) NOT NULL,
`COLLECTTIME` datetime NOT NULL
)
ENGINE=InnoDB (适用大部分引擎,可根据需要调整)
DEFAULT CHARSET=latin1(编码可根据需要修改)
PARTITION BY RANGE (to_days(COLLECTTIME))
(PARTITION pmin VALUES LESS THAN (to_days('2010-01-01')),
PARTITION p201001 VALUES LESS THAN (to_days('2010-02-01')) ,
PARTITION p201002 VALUES LESS THAN (to_days('2010-03-01')) ,
PARTITION p201003 VALUES LESS THAN (to_days('2010-04-01')) ,
PARTITION p201004 VALUES LESS THAN (to_days('2010-05-01')) ,
PARTITION p201005 VALUES LESS THAN (to_days('2010-06-01')) ,
PARTITION p201006 VALUES LESS THAN (to_days('2010-07-01')) ,
PARTITION p201007 VALUES LESS THAN (to_days('2010-08-01')) ,
PARTITION p201008 VALUES LESS THAN (to_days('2010-09-01')) ,
PARTITION p201009 VALUES LESS THAN (to_days('2010-10-01')) ,
PARTITION p201010 VALUES LESS THAN (to_days('2010-11-01')),
PARTITION p201011 VALUES LESS THAN (to_days('2010-12-01')),
PARTITION p201012 VALUES LESS THAN (to_days('2011-01-01')),
PARTITION p201101 VALUES LESS THAN (to_days('2011-02-01')),
PARTITION p201102 VALUES LESS THAN (to_days('2011-03-01')),
PARTITION p201103 VALUES LESS THAN (to_days('2011-04-01')),
PARTITION p201104 VALUES LESS THAN (to_days('2011-05-01')),
PARTITION p201105 VALUES LESS THAN (to_days('2011-06-01')),
PARTITION p201106 VALUES LESS THAN (to_days('2011-07-01')),
PARTITION p201107 VALUES LESS THAN (to_days('2011-08-01')),
PARTITION p201108 VALUES LESS THAN (to_days('2011-09-01')),
PARTITION p201109 VALUES LESS THAN (to_days('2011-10-01')),
PARTITION p201110 VALUES LESS THAN (to_days('2011-11-01')),
PARTITION p201111 VALUES LESS THAN (to_days('2011-12-01')),
PARTITION p201112 VALUES LESS THAN (to_days('2012-01-01')),
PARTITION pmax VALUES LESS THAN MAXVALUE );

2. 为现有表创建分区

Sql代码


alter table 表名
PARTITION BY RANGE (to_days(COLLECTTIME))
(PARTITION pmin VALUES LESS THAN (to_days('2010-01-01')),
PARTITION p201001 VALUES LESS THAN (to_days('2010-02-01')) ,
PARTITION p201002 VALUES LESS THAN (to_days('2010-03-01')) ,
PARTITION p201003 VALUES LESS THAN (to_days('2010-04-01')) ,
PARTITION p201004 VALUES LESS THAN (to_days('2010-05-01')) ,
PARTITION p201005 VALUES LESS THAN (to_days('2010-06-01')) ,
PARTITION p201006 VALUES LESS THAN (to_days('2010-07-01')) ,
PARTITION p201007 VALUES LESS THAN (to_days('2010-08-01')) ,
PARTITION p201008 VALUES LESS THAN (to_days('2010-09-01')) ,
PARTITION p201009 VALUES LESS THAN (to_days('2010-10-01')) ,
PARTITION p201010 VALUES LESS THAN (to_days('2010-11-01')),
PARTITION p201011 VALUES LESS THAN (to_days('2010-12-01')),
PARTITION p201012 VALUES LESS THAN (to_days('2011-01-01')),
PARTITION p201101 VALUES LESS THAN (to_days('2011-02-01')),
PARTITION p201102 VALUES LESS THAN (to_days('2011-03-01')),
PARTITION p201103 VALUES LESS THAN (to_days('2011-04-01')),
PARTITION p201104 VALUES LESS THAN (to_days('2011-05-01')),
PARTITION p201105 VALUES LESS THAN (to_days('2011-06-01')),
PARTITION p201106 VALUES LESS THAN (to_days('2011-07-01')),
PARTITION p201107 VALUES LESS THAN (to_days('2011-08-01')),
PARTITION p201108 VALUES LESS THAN (to_days('2011-09-01')),
PARTITION p201109 VALUES LESS THAN (to_days('2011-10-01')),
PARTITION p201110 VALUES LESS THAN (to_days('2011-11-01')),
PARTITION p201111 VALUES LESS THAN (to_days('2011-12-01')),
PARTITION p201112 VALUES LESS THAN (to_days('2012-01-01')),
PARTITION pmax VALUES LESS THAN MAXVALUE );

如果表中已有数据,分区时会自动进行分区存储,不必担心数据丢失或者手动分类数据.

3. 删除表中的指定分区

Sql代码


ALTER TABLE 表名 DROP PARTITION 分区名;

删除分区会导致分区数据丢失,建议先备份.

4. 追加表分区

Sql代码


ALTER TABLE 表名 DROP PARTITION pmax;
ALTER TABLE 表名
ADD PARTITION (
PARTITION p201201 VALUES LESS THAN (to_days('2012-2-1')),
PARTITION pmax VALUES LESS THAN MAXVALUE);

需要先删除MAXVALUE分区后增加分区后再重建MAXVALUE分区,删除前需要先备份MAXVALUE分区数据.

5. 查看标分区信息

Sql代码


SELECT
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
FROM
INFORMATION_SCHEMA.partitions
WHERE
TABLE_SCHEMA = schema()
AND TABLE_NAME='表名';

6. 查看查询语句涉及分区信息

Sql代码


explain partitions
select … from 表名 where …;

该操作只查看查询语句相关的分区信息,不会返回查询结果.

以上是我对MySQL的初体验总结,没啥心得体会,只有一点点成就感,希望和大家分享.

另外分区表尚存在问题:

1,是否可将分区表设置在不同硬盘,innodb可行?

2,是否可根据多条件进行水平分区,类似group by 列1,列2...

3,是否能将分区设置成不同引擎,例如当前使用中的分区为innodb,老的分区使用MyISAM.

7.分区的合并

下面的SQL，将p201001
- p201009 合并为3个分区p2010Q1 - p2010Q3
mysql> ALTER TABLE sale_data
-> REORGANIZE PARTITION p201001,p201002,p201003,
-> p201004,p201005,p201006,
-> p201007,p201008,p201009 INTO
-> (
-> PARTITION p2010Q1 VALUES LESS THAN (201004),
-> PARTITION p2010Q2 VALUES LESS THAN (201007),
-> PARTITION p2010Q3 VALUES LESS THAN (201010)
-> );
Query OK, 0 rows affected (1.14 sec)
Records: 0 Duplicates: 0 Warnings: 0