MySQL 是否支持分区功能查询

MySQL在5.1之后才支持分区功能，但查询是否支持分区的方法不一样。

MySQL5.1中使用：

SHOW VARIABLES LIKE '%partition%';

显示结果为：

+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| have_partition_engine | YES   |
+-----------------------+-------+

表示支持分区表。

MySQL5.6中使用：SHOW PLUGINS; 来查询。

SHOW PLUGINS;

显示结果为：

+------------+----------+----------------+---------+---------+
| Name       | Status   | Type           | Library | License |
+------------+----------+----------------+---------+---------+
| binlog     | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| partition  | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| ARCHIVE    | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| BLACKHOLE  | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| CSV        | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| FEDERATED  | DISABLED | STORAGE ENGINE | NULL    | GPL     |
| MEMORY     | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| InnoDB     | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| MRG_MYISAM | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| MyISAM     | ACTIVE   | STORAGE ENGINE | NULL    | GPL     |
| ndbcluster | DISABLED | STORAGE ENGINE | NULL    | GPL     |
+------------+----------+----------------+---------+---------+
11 rows in set (0.00 sec)

partion状态为ACTIVE表示支持分区。 或者用一条查询语句来检查INFORMATION_SCHEMA.PLUGINS 表：

SELECT 	PLUGIN_NAME as Name, 
       	PLUGIN_VERSION as Version, 
    	PLUGIN_STATUS as Status 
    	FROM INFORMATION_SCHEMA.PLUGINS 
    	WHERE PLUGIN_TYPE='STORAGE ENGINE';

若是显示结果为

+--------------------+---------+--------+
| Name               | Version | Status |
+--------------------+---------+--------+
| binlog             | 1.0     | ACTIVE |
| CSV                | 1.0     | ACTIVE |
| MEMORY             | 1.0     | ACTIVE |
| MRG_MYISAM         | 1.0     | ACTIVE |
| MyISAM             | 1.0     | ACTIVE |
| PERFORMANCE_SCHEMA | 0.1     | ACTIVE |
| BLACKHOLE          | 1.0     | ACTIVE |
| ARCHIVE            | 3.0     | ACTIVE |
| InnoDB             | 5.6     | ACTIVE |
| partition          | 1.0     | ACTIVE |
+--------------------+---------+--------+
10 rows in set (0.00 sec)

partion为ACTIVE表示支持分区。

MySQL查看和新增表分区 一、查看表分区

SELECT
  partition_name part, 
  partition_expression expr, 
  partition_description descr, 
  FROM_DAYS(partition_description) lessthan_sendtime, 
  table_rows 
FROM
  INFORMATION_SCHEMA.partitions 
WHERE
  TABLE_SCHEMA = SCHEMA() 
  AND TABLE_NAME='td_sendmessagelog'; ---这里是表名

二、添加表分区

ALTER TABLE td_sendmessagelog ADD PARTITION (
   PARTITION p20150210 VALUES LESS THAN (TO_DAYS('2015-02-10')),
  PARTITION p20150220 VALUES LESS THAN (TO_DAYS('2015-02-20')),
  PARTITION p20150301 VALUES LESS THAN (TO_DAYS('2015-03-01')),
  PARTITION p20150310 VALUES LESS THAN (TO_DAYS('2015-03-10')),
  PARTITION p20150320 VALUES LESS THAN (TO_DAYS('2015-03-20')),
  PARTITION p20150401 VALUES LESS THAN (TO_DAYS('2015-04-01')),
  PARTITION p20150410 VALUES LESS THAN (TO_DAYS('2015-04-10')),
  PARTITION p20150420 VALUES LESS THAN (TO_DAYS('2015-04-20')),
  PARTITION p20150501 VALUES LESS THAN (TO_DAYS('2015-05-01')),
  PARTITION pmax VALUES LESS THAN (maxvalue)
  );

注意：建立表分区，要指定对应的列。上面例子，用的是一个时间列（sendtime） 建立表过程以下（注意指定的primary key）：

create table td_sendmessagelog  
(  
   id                   int not null,  
   sendtime                 datetime not null
   primary key (id,sendtime)  
)  
建立索引：
create index Index_sid_sendtime on td_sendmessagelog  
(  
   sid,  
   sendtime  
);