【转载】实战mysql分区(PARTITION)

TABLE `xxxxxxxx` ( `crttm` int(11) NOT NULL, `srvid` int(11) NOT NULL, `evtid` int(11) NOT NULL, `aid` int(11) NOT NULL, `rid` int(11) NOT NULL, `itmid` int(11) NOT NULL, `itmnum` int(11) NOT NULL, `gdtype` int(11) NOT NULL, `gdnum` int(11) NOT NULL, `islmt` int(11) NOT NULL, KEY `crttm` (`crttm`), KEY `itemid` (`itmid`), KEY `srvid` (`srvid`), KEY `gdtype` (`gdtype`) ) ENGINE=myisam DEFAULT CHARSET=utf8 PARTITION BY RANGE (crttm) ( PARTITION p201303 VALUES LESS THAN (unix_timestamp(‘2013-04-01‘)), PARTITION p201304 VALUES LESS THAN (unix_timestamp(‘2013-05-01‘)), PARTITION p201305 VALUES LESS THAN (unix_timestamp(‘2013-06-01‘)), PARTITION p201306 VALUES LESS THAN (unix_timestamp(‘2013-07-01‘)), PARTITION p201307 VALUES LESS THAN (unix_timestamp(‘2013-08-01‘)), PARTITION p201308 VALUES LESS THAN (unix_timestamp(‘2013-09-01‘)), PARTITION p201309 VALUES LESS THAN (unix_timestamp(‘2013-10-01‘)), PARTITION p201310 VALUES LESS THAN (unix_timestamp(‘2013-11-01‘)), PARTITION p201311 VALUES LESS THAN (unix_timestamp(‘2013-12-01‘)), PARTITION p201312 VALUES LESS THAN (unix_timestamp(‘2014-01-01‘)), PARTITION p201401 VALUES LESS THAN (unix_timestamp(‘2014-02-01‘)) );

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())

 

将旧的表数据导入到新表后，看到新表的数据都分布到不同的区了！

 

维护命令：

添加分区

Sql代码

alter table xxxxxxx add partition (partition p0 values less than(1991));  //只能添加大于分区键的分区

删除分区

Sql代码

alter table xxxxxxx drop partition p0; //可以删除任意分区

删除分区数据

alter table xxxxxx  truncate partition p1,p2;
alter table xxxxxx  truncate partition all;
或
delete from xxxxxx 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 xxxxx 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 xxxxxx 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 xxxxxx analyze partition pm1/all;

check表

alter  table xxxxxx 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
//查看分区使用情况

select a.PARTITION_NAME part,a.PARTITION_EXPRESSION expr,a.PARTITION_DESCRIPTION descr,a.TABLE_ROWS
from information_schema.PARTITIONS a
where TABLE_SCHEMA=schema()
and table_name=‘rc3‘;

 

【转载】实战mysql分区(PARTITION)

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