author：skate
time：2012/11/28
mysql分区表---range partition
range partition
创建范围分区：
CREATE TABLE `employees1` (
`id` int(11) NOT NULL,
`fname` varchar(30) DEFAULT NULL,
`lname` varchar(30) DEFAULT NULL,
`hired` date NOT NULL DEFAULT '1970-01-01',
`separated` date NOT NULL DEFAULT '9999-12-31',
`job_code` int(11) NOT NULL,
`store_id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE (store_id)
(PARTITION p0 VALUES LESS THAN (6) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (11) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (16) ENGINE = InnoDB,
PARTITION p3 VALUES LESS THAN (21) ENGINE = InnoDB) */
使用函数表达式创建范围分区
CREATE TABLE `employees2` (
`id` int(11) NOT NULL,
`fname` varchar(30) DEFAULT NULL,
`lname` varchar(30) DEFAULT NULL,
`hired` date NOT NULL DEFAULT '1970-01-01',
`separated` date NOT NULL DEFAULT '9999-12-31',
`job_code` int(11) DEFAULT NULL,
`store_id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
/*!50100 PARTITION BY RANGE ( YEAR(separated))
(PARTITION pm1 VALUES LESS THAN (2006) ENGINE = InnoDB,
PARTITION pm2 VALUES LESS THAN (2011) ENGINE = InnoDB) */
维护命令：
添加分区
alter table employees2 add partition (partition p0 values less than(1991)); //只能添加大于分区键的分区
删除分区
alter table employees2 drop partition p0; //可以删除任意分区
删除分区数据
alter table employees2 truncate partition p1,p2;
alter table employees2 truncate partition all;
或
delete from employees2 where separated < '2006-01-01' or (separated >= '2006-01-01' and separated<'2011-01-01');
重定义分区（包括重命名分区，伴随移动数据；合并分区)
alter table employees2 reorganize partition p1,p3,p4 into (partition pm1 values less than(2006),
partition pm2 values less than(2011));
rebuild重建分区
alter table employees2 rebuild partition pm1/all; //相当于drop所有记录，然后再reinsert；可以解决磁盘碎片
优化表
alter table tt2 optimize partition pm1; //在大量delete表数据后，可以回收空间和碎片整理。但在5.5.30后支持。在5.5.30之前可以通过recreate+analyze来替代，如果用rebuild+analyze速度慢
analzye表
alter table employees2 analyze partition pm1/all;
check表
alter table employees2 check partition pm1/all;
show create table employees2; //查看分区表的定义
show table status like 'employees2'\G; //查看表时候是分区表 如“Create_options: partitioned”
select * from information_schema.KEY_COLUMN_USAGE where table_name='employees2'; //查看索引
SELECT * FROM information_schema.partitions WHERE table_name='employees2' //查看分区表
explain partitions select * from employees2 where separated < '1990-01-01' or separated > '2016-01-01'; //查看分区是否被select使用
注意：
1. primary key和unique key必须包含在分区key的一部分，否则在创建primary key和unique index时会报”ERROR 1503 (HY000)“
mysql> create unique index idx_employees1_job_code on employees1(job_code);
ERROR 1503 (HY000): A UNIQUE INDEX must include all columns in the table's partitioning function
或
mysql> ALTER TABLE `skate`.`employees1` ADD PRIMARY KEY (`id`) ;
ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function
2. 范围分区添加分区只能在最大值后面追加分区
3. 所有分区的engine必须一样
4. 范围分区分区字段：integer、数值表达式、日期列，日期函数表达式(如year(),to_days(),to_seconds(),unix_timestamp())
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