mysql 表分区案例_mysql表分区案例

0、整理表空间碎片

optimize table tablename

1、表分区按年分区，季度子分区

alter tablekey_part

partitionby range(year(create_time))

subpartitionbyhash(quarter(create_time))

subpartitions4(

partition p0values less than (2015),

partition p2015values less than (2016),

partition p2016values less than (2017),

partition p2017values less than (2018),

partition p2018values less than (2019),

partition p1valuesless than maxvalue

);

总共产生24个分区，1年4个季度，6年24个季度。

2、按照天分区月表

create_time支持如下日期格式：

%Y-%c-%d

%Y-%c-%d %h:%i:%s

alter tableaa

partitionbyrange (to_days(create_time)) (

partition p01values less than (to_days('2018-04-01')) engine =innodb,

partition p02values less than (to_days('2018-04-02')) engine =innodb,

partition p03values less than (to_days('2018-04-03')) engine =innodb,

partition p04values less than (to_days('2018-04-04')) engine =innodb,

partition p05values less than (to_days('2018-04-05')) engine =innodb,

partition p06values less than (to_days('2018-04-06')) engine =innodb,

partition p07values less than (to_days('2018-04-07')) engine =innodb,

partition p08values less than (to_days('2018-04-08')) engine =innodb,

partition p09values less than (to_days('2018-04-09')) engine =innodb,partition p10values less than MAXVALUE engine =innodb

);

explain partitions select * from key_part where create_time>='2018-04-12' and create_time<='2018-04-15'

可以看到只遍历了4个分区表，只扫描了4行，而不是扫描所有的行。

explain partitions select * from key_part where create_time>='2018-04-27'

可以看到只遍历了5个分区表，只扫描了5行，而不是扫描所有的行。

3、按照年分区表

alter table user partition by linear hash(year(create_time)) partitions 12;

在5.7版本之前，对于data和datetime类型的列，如果要实现分区裁剪，只能使用year() 和to_days()函数，在5.7版本中，又新增了to_seconds()函数。

这是因为表分区时，分区字段必须包含在主键字段内或唯一索引内，一张表只能有一个主键或一个唯一索引，主键和唯一索引不能同时存在

CREATE TABLE`key_part` (

`news_id`int(11) NOT NULL COMMENT '新闻id',

`content`varchar(1000) NOT NULL DEFAULT '' COMMENT '新闻内容',

`u_id`varchar(25) NOT NULL DEFAULT '' COMMENT '来源ip',

`create_time`datetime NOT NULL COMMENT '时间',PRIMARY KEY (`u_id`,`create_time`),KEY`create_time` (`create_time`) USING BTREE,KEY`aa` (`news_id`) USING BTREE

) ENGINE=InnoDB DEFAULT CHARSET=utf8/*!50500 PARTITION BY RANGE COLUMNS(create_time)

(PARTITION p01 VALUES LESS THAN ('2018-01-01') ENGINE = InnoDB,

PARTITION p02 VALUES LESS THAN ('2018-03-01') ENGINE = InnoDB,

PARTITION p03 VALUES LESS THAN ('2018-05-01') ENGINE = InnoDB,

PARTITION p04 VALUES LESS THAN ('2018-07-01') ENGINE = InnoDB,

PARTITION p05 VALUES LESS THAN ('2018-09-01') ENGINE = InnoDB,

PARTITION p06 VALUES LESS THAN ('2018-11-01') ENGINE = InnoDB,

PARTITION p07 VALUES LESS THAN ('2019-01-01') ENGINE = InnoDB,

PARTITION p08 VALUES LESS THAN ('2020-01-01') ENGINE = InnoDB,

PARTITION p09 VALUES LESS THAN (MAXVALUE) ENGINE = InnoDB)*/;

5、Columns分区

alter tablekey_part

partitionbyrange columns(create_time) (

partition p01values less than ('2018-01-01') engine =innodb,

partition p02values less than ('2018-03-01') engine =innodb,

partition p03values less than ('2018-05-01') engine =innodb,

partition p04values less than ('2018-07-01') engine =innodb,

partition p05values less than ('2018-09-01') engine =innodb,

partition p06values less than ('2018-11-01') engine =innodb,

partition p07values less than ('2019-01-01') engine =innodb,

partition p08values less than ('2020-01-01') engine =innodb,

partition p09values less than maxvalue engine =innodb

);

6、添加表分区

--对表重新表分区

alter table lot_order_aa partition by range columns(create_time)(partition p03 valuesless than ('2018-03-01'));--在已有分区的表上，添加表分区

alter table lot_order_aa add partition (partition p05 valuesless than ('2018-05-01'));