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【分享】Mysql分区表的管理与维护

数据存储 摘星怪 609浏览 0评论

改变一个表的分区方案只需使用alter table 加 partition_options 子句就可以了。和创建分区表时的create table语句很像

创建分区表:

CREATE TABLE trb3 (

id INT, name VARCHAR(50), purchased DATE)

PARTITION BY RANGE( YEAR(purchased) ) (

PARTITION p0 VALUES LESS THAN (1990),

PARTITION p1 VALUES LESS THAN (1995),

PARTITION p2 VALUES LESS THAN (2000),

PARTITION p3 VALUES LESS THAN (2005)

);

创建插入数据存储过程:

delimiter $$

drop procedure if exists pr_trb3$$

create procedure pr_trb3(in begindate date,in enddate date,in tabname varchar(40))

begin

while begindate<enddate

do

set @s=concat_ws(‘ ‘,’insert into’,tabname,’values(1,”fanboshi”,”’,begindate,”’)’);

prepare stmt from @s;

execute stmt;

drop prepare stmt;

set begindate = date_add(begindate,interval 1 day);

end while;

end$$

delimiter ;

调用存储过程插入数据

call pr_trb3(‘1985-01-01′,’2004-12-31′,’trb3’);

查看数据分布:

select

partition_name part,

partition_expression expr,

partition_description descr,

table_rows

from information_schema.partitions where

table_schema = schema()

and table_name=’trb3′;

+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
+——+——————+——-+————+

4 rows in set (0.00 sec)

改变分区方案:

mysql> ALTER TABLE trb3 PARTITION BY KEY(id) PARTITIONS 4;

Query OK, 7304 rows affected (0.07 sec)

Records: 7304 Duplicates: 0 Warnings: 0

查看数据:

select
partition_name part,

partition_expression expr,

partition_description descr,

table_rows

from information_schema.partitions where

table_schema = schema()

and table_name=’trb3′;

+——+——+——-+————+
| part | expr | descr | table_rows |
+——+——+——-+————+
| p0 | `id` | NULL | 7472 |
| p1 | `id` | NULL | 0 |
| p2 | `id` | NULL | 0 |
| p3 | `id` | NULL | 0 |
+——+——+——-+————+

4 rows in set (0.00 sec)

mysql> select 1826*4;

+——–+
| 1826*4 |
+——–+
| 7304 |
+——–+

1 row in set (0.00 sec)

count(*)行数一致,说明数据没出问题,但是information_schema.partitions查出来的不对,这就不知道为什么了

For partitioned InnoDB tables, the row count given in the TABLE_ROWS column of the INFORMATION_SCHEMA.PARTITIONS table is only an estimated value used in SQL optimization, and is not always exact.

mysql> select count(*) from trb3;

+———-+
| count(*) |
+———-+
| 7304 |
+———-+

但是count(*)还是7304,什么鬼

再次改变分区方案

ALTER TABLE trb3

PARTITION BY RANGE( YEAR(purchased) ) (

PARTITION p0 VALUES LESS THAN (1990),

PARTITION p1 VALUES LESS THAN (1995),

PARTITION p2 VALUES LESS THAN (2000),

PARTITION p3 VALUES LESS THAN (2005)

);

mysql> select

-> partition_name part,

-> partition_expression expr,

-> partition_description descr,

-> table_rows

-> from information_schema.partitions where

-> table_schema = schema()

-> and table_name=’trb3′;

+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 0 |
| p3 | YEAR(purchased) | 2005 | 0 |
+——+——————+——-+————+

4 rows in set (0.00 sec)

丢数据了。。 更正,实际没丢,这个information_shcema.partitions表有延迟,过一会再查就好了

mysql> select

-> partition_name part,

-> partition_expression expr,

-> partition_description descr,

-> table_rows

-> from information_schema.partitions where

-> table_schema = schema()

-> and table_name=’trb3′;

+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
+——+——————+——-+————+

4 rows in set (0.00 sec)

官方文档说:
This has the same effect on the structure of the table as dropping the table and re-creating it using CREATE TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2;

就是说ALTER TABLE trb3 PARTITION BY与 drop table然后重新create table trb3 partition by key(id) partitions 2一样呢。

改存储引擎,和普通表没啥区别

mysql> drop table trb3;

Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE)

-> PARTITION BY RANGE( YEAR(purchased) ) (

-> PARTITION p0 VALUES LESS THAN (1990),

-> PARTITION p1 VALUES LESS THAN (1995),

-> PARTITION p2 VALUES LESS THAN (2000),

-> PARTITION p3 VALUES LESS THAN (2005)

-> );

Query OK, 0 rows affected (0.03 sec)

mysql> call pr_trb3(‘1985-01-01′,’2004-12-31′,’trb3’);

Query OK, 0 rows affected (1.69 sec)

mysql> select

-> partition_name part,

-> partition_expression expr,

-> partition_description descr,

-> table_rows

-> from information_schema.partitions where

-> table_schema = schema()

-> and table_name=’trb3′;

+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
+——+——————+——-+————+

4 rows in set (0.01 sec)

mysql> alter table trb3 engine=myisam;

Query OK, 7304 rows affected (0.02 sec)

Records: 7304 Duplicates: 0 Warnings: 0

mysql> select

-> partition_name part,

-> partition_expression expr,

-> partition_description descr,

-> table_rows

-> from information_schema.partitions where

-> table_schema = schema()

-> and table_name=’trb3′;

+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
+——+——————+——-+————+

4 rows in set (0.01 sec)

mysql> show create table trb3\G

*************************** 1. row ***************************
Table: trb3

Create Table: CREATE TABLE `trb3` (

`id` int(11) DEFAULT NULL,

`name` varchar(50) DEFAULT NULL,

`purchased` date DEFAULT NULL

) ENGINE=MyISAM DEFAULT CHARSET=utf8

/*!50100 PARTITION BY RANGE ( YEAR(purchased))

(PARTITION p0 VALUES LESS THAN (1990) ENGINE = MyISAM,

PARTITION p1 VALUES LESS THAN (1995) ENGINE = MyISAM,

PARTITION p2 VALUES LESS THAN (2000) ENGINE = MyISAM,

PARTITION p3 VALUES LESS THAN (2005) ENGINE = MyISAM) */

1 row in set (0.00 sec)

将表由分区表改为非分区表:

mysql> alter table trb3 remove partitioning;

Query OK, 7304 rows affected (0.01 sec)

Records: 7304 Duplicates: 0 Warnings: 0

mysql> select
-> partition_name part,
-> partition_expression expr,
-> partition_description descr,
-> table_rows
-> from information_schema.partitions where
-> table_schema = schema()
-> and table_name=’trb3′;
+——+——+——-+————+
| part | expr | descr | table_rows |
+——+——+——-+————+
| NULL | NULL | NULL | 7304 |
+——+——+——-+————+
1 row in set (0.00 sec)

mysql> show create table trb3\G
*************************** 1. row ***************************
Table: trb3
Create Table: CREATE TABLE `trb3` (
`id` int(11) DEFAULT NULL,
`name` varchar(50) DEFAULT NULL,
`purchased` date DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

Range List分区管理

mysql> drop table trb3;
Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE)
-> PARTITION BY RANGE( YEAR(purchased) ) (
-> PARTITION p0 VALUES LESS THAN (1990),
-> PARTITION p1 VALUES LESS THAN (1995),
-> PARTITION p2 VALUES LESS THAN (2000),
-> PARTITION p3 VALUES LESS THAN (2005)
-> );
Query OK, 0 rows affected (0.03 sec)

mysql> call pr_trb3(‘1985-01-01′,’2004-12-31′,’trb3’);
Query OK, 0 rows affected (1.75 sec)

mysql> select
-> partition_name part,
-> partition_expression expr,
-> partition_description descr,
-> table_rows
-> from information_schema.partitions where
-> table_schema = schema()
-> and table_name=’trb3′;
+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
+——+——————+——-+————+
4 rows in set (0.00 sec)

增加分区

mysql> alter table trb3 add partition (partition p5 values less than(2010));
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0

合并分区

mysql> alter table trb3 reorganize partition p3,p5 into(partition p5 values less than(2010));
Query OK, 1826 rows affected (0.03 sec)
Records: 1826 Duplicates: 0 Warnings: 0

mysql> select
-> partition_name part,
-> partition_expression expr,
-> partition_description descr,
-> table_rows
-> from information_schema.partitions where
-> table_schema = schema()
-> and table_name=’trb3′;
+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p5 | YEAR(purchased) | 2010 | 1826 |
+——+——————+——-+————+
4 rows in set (0.00 sec)

分裂分区

mysql> ALTER TABLE trb3 REORGANIZE PARTITION p5 INTO (
-> PARTITION p3 VALUES LESS THAN (2005),
-> PARTITION p4 VALUES LESS THAN (2010)
-> );
Query OK, 1826 rows affected (0.04 sec)
Records: 1826 Duplicates: 0 Warnings: 0

select
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’trb3′;
+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | 1990 | 1826 |
| p1 | YEAR(purchased) | 1995 | 1826 |
| p2 | YEAR(purchased) | 2000 | 1826 |
| p3 | YEAR(purchased) | 2005 | 1826 |
| p4 | YEAR(purchased) | 2010 | 0 |
+——+——————+——-+————+
5 rows in set (0.00 sec)

HASH KEY分区

CREATE TABLE trb3 (id INT, name VARCHAR(50), purchased DATE)
PARTITION BY hash( YEAR(purchased) )
partitions 12;

mysql>call pr_trb3(‘1985-01-01′,’2004-12-31′,’trb3’);

select
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’trb3′;
+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | NULL | 731 |
| p1 | YEAR(purchased) | NULL | 365 |
| p2 | YEAR(purchased) | NULL | 365 |
| p3 | YEAR(purchased) | NULL | 365 |
| p4 | YEAR(purchased) | NULL | 366 |
| p5 | YEAR(purchased) | NULL | 730 |
| p6 | YEAR(purchased) | NULL | 730 |
| p7 | YEAR(purchased) | NULL | 730 |
| p8 | YEAR(purchased) | NULL | 732 |
| p9 | YEAR(purchased) | NULL | 730 |
| p10 | YEAR(purchased) | NULL | 730 |
| p11 | YEAR(purchased) | NULL | 730 |
+——+——————+——-+————+
12 rows in set (0.00 sec)

缩建分区从12个到8个

mysql> ALTER TABLE trb3 COALESCE PARTITION 4;
Query OK, 7304 rows affected (0.13 sec)
Records: 7304 Duplicates: 0 Warnings: 0

select
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’trb3′;
+——+——————+——-+————+
| part | expr | descr | table_rows |
+——+——————+——-+————+
| p0 | YEAR(purchased) | NULL | 732 |
| p1 | YEAR(purchased) | NULL | 1095 |
| p2 | YEAR(purchased) | NULL | 1095 |
| p3 | YEAR(purchased) | NULL | 1095 |
| p4 | YEAR(purchased) | NULL | 1097 |
| p5 | YEAR(purchased) | NULL | 730 |
| p6 | YEAR(purchased) | NULL | 730 |
| p7 | YEAR(purchased) | NULL | 730 |
+——+——————+——-+————+
8 rows in set (0.00 sec)

mysql> select count(*) from trb3;
+———-+
| count(*) |
+———-+
| 7304 |
+———-+
1 row in set (0.00 sec)

没丢数据

收缩前2004年在P0

mysql> select mod(2004,12);
+————–+
| mod(2004,12) |
+————–+
| 0 |
+————–+

收缩后2004年在P4

mysql> select mod(2004,8);
+————-+
| mod(2004,8) |
+————-+
| 4 |
+————-+

Exchanging Partitions and Subpartitions with Tables

分区(子分区)交换

ALTER TABLE pt EXCHANGE PARTITION p WITH TABLE nt

pt是一个分区表,p是pt的分区或子分区,而nt是一个非分区表

限制条件:
1.表nt不是分区表
2.表nt不是临时表
3.表pt和nt结构在其他方面是相同的
4.表n没有外键约束,也没有其他表引用它的列为外键
5.表nt的所有行都包含在表p的分区范围内(比如p range分区最大values less than 10,那么表nt不能有大于等于10的值)

权限:
除了 ALTER, INSERT, and CREATE 权限外,你还要有DROP权限才能执行ALTER TABLE … EXCHANGE PARTITION.

其他注意事项:
1.执行ALTER TABLE … EXCHANGE PARTITION 不会调用任何在nt表和p表上的触发器
2.在交换表中的任何AUTO_INCREMENT列会被reset
3.IGNORE关键字在执行ALTER TABLE … EXCHANGE PARTITION时会失效

完整实例语句如下:
ALTER TABLE pt
EXCHANGE PARTITION p
WITH TABLE nt;

在一次ALTER TABLE EXCHANGE PARTITION 中,只能有一个分区和一个非分区表被交换
想交换多个,就执行多次ALTER TABLE EXCHANGE PARTITION

任何MySQL支持的分区类型都可以进行交换

交换实例

CREATE TABLE e (
id INT NOT NULL,
fname VARCHAR(30),
lname VARCHAR(30)
)
PARTITION BY RANGE (id) (
PARTITION p0 VALUES LESS THAN (50),
PARTITION p1 VALUES LESS THAN (100),
PARTITION p2 VALUES LESS THAN (150),
PARTITION p3 VALUES LESS THAN (MAXVALUE)
);

INSERT INTO e VALUES
(1669, “Jim”, “Smith”),
(337, “Mary”, “Jones”),
(16, “Frank”, “White”),
(2005, “Linda”, “Black”);

创建一个与e结构一样的非分区表e2

mysql> create table e2 like e;
Query OK, 0 rows affected (0.01 sec)

mysql> show create table e2\G
*************************** 1. row ***************************
Table: e2
Create Table: CREATE TABLE `e2` (
`id` int(11) NOT NULL,
`fname` varchar(30) DEFAULT NULL,
`lname` varchar(30) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (id)
(PARTITION p0 VALUES LESS THAN (50) ENGINE = InnoDB,
PARTITION p1 VALUES LESS THAN (100) ENGINE = InnoDB,
PARTITION p2 VALUES LESS THAN (150) ENGINE = InnoDB,
PARTITION p3 VALUES LESS THAN MAXVALUE ENGINE = InnoDB) */
1 row in set (0.00 sec)

mysql> alter table e2 remove partitioning;
Query OK, 0 rows affected (0.02 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> show create table e2\G
*************************** 1. row ***************************
Table: e2
Create Table: CREATE TABLE `e2` (
`id` int(11) NOT NULL,
`fname` varchar(30) DEFAULT NULL,
`lname` varchar(30) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

查看数据在e表中的分布:

select
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’e’
+——+——+———-+————+
| part | expr | descr | table_rows |
+——+——+———-+————+
| p0 | id | 50 | 1 |
| p1 | id | 100 | 0 |
| p2 | id | 150 | 0 |
| p3 | id | MAXVALUE | 3 |
+——+——+———-+————+
4 rows in set (0.00 sec)

将分区p0与e2表进行交换:

mysql> ALTER TABLE e EXCHANGE PARTITION p0 WITH TABLE e2;
Query OK, 0 rows affected (0.01 sec)

select
partition_name part,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’e’;
+——+——+———-+————+
| part | expr | descr | table_rows |
+——+——+———-+————+
| p0 | id | 50 | 0 |
| p1 | id | 100 | 0 |
| p2 | id | 150 | 0 |
| p3 | id | MAXVALUE | 3 |
+——+——+———-+————+
4 rows in set (0.01 sec)

mysql> select * from e2;
+—-+——-+——-+
| id | fname | lname |
+—-+——-+——-+
| 16 | Frank | White |
+—-+——-+——-+
1 row in set (0.00 sec)

重做实验,这次在交换前在表e2中插入一些数据

mysql> insert into e2 values(16,’FAN’,’BOSHI’);
Query OK, 1 row affected (0.00 sec)

mysql> insert into e2 values(51,’DU’,’YALAN’);
Query OK, 1 row affected (0.00 sec)

mysql> select * from e2;
+—-+——-+——-+
| id | fname | lname |
+—-+——-+——-+
| 16 | FAN | BOSHI |
| 51 | DU | YALAN |
+—-+——-+——-+
2 rows in set (0.00 sec)

mysql> ALTER TABLE e EXCHANGE PARTITION p0 WITH TABLE e2;
ERROR 1737 (HY000): Found a row that does not match the partition

报错了,因为51超出了p0的范围。 如之前所说,此时使用IGNORE也无济于事

mysql> ALTER IGNORE TABLE e EXCHANGE PARTITION p0 WITH TABLE e2;
ERROR 1737 (HY000): Found a row that does not match the partition

修改id为49,这样就属于p0的范围了

mysql> update e2 set id=49 where id=51;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0

mysql> ALTER TABLE e EXCHANGE PARTITION p0 WITH TABLE e2;
Query OK, 0 rows affected (0.01 sec)

mysql> select

-> partition_name part,
-> partition_expression expr,
-> partition_description descr,
-> table_rows
-> from information_schema.partitions where
-> table_schema = schema()
-> and table_name=’e’;
+——+——+———-+————+
| part | expr | descr | table_rows |
+——+——+———-+————+
| p0 | id | 50 | 2 |
| p1 | id | 100 | 0 |
| p2 | id | 150 | 0 |
| p3 | id | MAXVALUE | 3 |
+——+——+———-+————+
4 rows in set (0.00 sec)

e2的数据被交换到了p0中

mysql> select * from e partition(p0);
+—-+——-+——-+
| id | fname | lname |
+—-+——-+——-+
| 16 | FAN | BOSHI |
| 49 | DU | YALAN |
+—-+——-+——-+
2 rows in set (0.00 sec)

e的p0分区中的数据被交换到了e2中

mysql> select * from e2;
+—-+——-+——-+
| id | fname | lname |
+—-+——-+——-+
| 16 | Frank | White |
+—-+——-+——-+
1 row in set (0.01 sec)

交换subpartition

CREATE TABLE es (
id INT NOT NULL,
fname VARCHAR(30),
lname VARCHAR(30)
)
PARTITION BY RANGE (id)
SUBPARTITION BY KEY (lname)
SUBPARTITIONS 2 (
PARTITION p0 VALUES LESS THAN (50),
PARTITION p1 VALUES LESS THAN (100),
PARTITION p2 VALUES LESS THAN (150),
PARTITION p3 VALUES LESS THAN (MAXVALUE)
);

INSERT INTO es VALUES
(1669, “Jim”, “Smith”),
(337, “Mary”, “Jones”),
(16, “Frank”, “White”),
(2005, “Linda”, “Black”);

CREATE TABLE es2 LIKE es;

ALTER TABLE es2 REMOVE PARTITIONING;

尽管我们没有显示的指定每个子分区的名字,我们仍可以通过information_schema.partitions表获取到子分区的名字

select
partition_name part,
subpartition_name,
partition_expression expr,
partition_description descr,
table_rows
from information_schema.partitions where
table_schema = schema()
and table_name=’es’;

+——+——————-+——+———-+————+
| part | subpartition_name | expr | descr | table_rows |
+——+——————-+——+———-+————+
| p0 | p0sp0 | id | 50 | 1 |
| p0 | p0sp1 | id | 50 | 0 |
| p1 | p1sp0 | id | 100 | 0 |
| p1 | p1sp1 | id | 100 | 0 |
| p2 | p2sp0 | id | 150 | 0 |
| p2 | p2sp1 | id | 150 | 0 |
| p3 | p3sp0 | id | MAXVALUE | 3 |
| p3 | p3sp1 | id | MAXVALUE | 0 |
+——+——————-+——+———-+————+

接下来,开始将p3sp0和es进行交换

mysql> select * from es partition(p3sp0);
+——+——-+——-+
| id | fname | lname |
+——+——-+——-+
| 1669 | Jim | Smith |
| 337 | Mary | Jones |
| 2005 | Linda | Black |
+——+——-+——-+
3 rows in set (0.00 sec)

mysql> ALTER TABLE es EXCHANGE PARTITION p3sp0 WITH TABLE es2;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from es partition(p3sp0);
Empty set (0.00 sec)

mysql> select * from es2;

+——+——-+——-+
| id | fname | lname |
+——+——-+——-+
| 1669 | Jim | Smith |
| 337 | Mary | Jones |
| 2005 | Linda | Black |
+——+——-+——-+

3 rows in set (0.00 sec)

如果一个分区表有子分区,那么你只能以子分区为粒度进行交换,而不能直接交换子分区的父分区

mysql> ALTER TABLE es EXCHANGE PARTITION p3 WITH TABLE es2;
ERROR 1704 (HY000): Subpartitioned table, use subpartition instead of partition

EXCHANGE PARTITION有着严格的要求

两个将要交换的表的 列名,列的创建顺序,列的数量,以及索引都要严格一致。当然存储引擎也要一致

mysql> desc es2;

+——-+————-+——+—–+———+——-+
| Field | Type | Null | Key | Default | Extra |
+——-+————-+——+—–+———+——-+
| id | int(11) | NO | | NULL | |
| fname | varchar(30) | YES | | NULL | |
| lname | varchar(30) | YES | | NULL | |
+——-+————-+——+—–+———+——-+

3 rows in set (0.00 sec)

mysql> create index id_name on es2(id,fname);
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> ALTER TABLE es EXCHANGE PARTITION p3sp0 WITH TABLE es2;
ERROR 1736 (HY000): Tables have different definitions

改变es2的存储引擎

mysql> drop index id_name on es2;
Query OK, 0 rows affected (0.00 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> alter table es2 engine=myisam;
Query OK, 0 rows affected (0.01 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql> ALTER TABLE es EXCHANGE PARTITION p3sp0 WITH TABLE es2;
ERROR 1497 (HY000): The mix of handlers in the partitions is not allowed in this version of MySQL

分区表的维护

CHECK TABLE, OPTIMIZE TABLE, ANALYZE TABLE, and REPAIR TABLE可以被用于维护分区表

Rebuilding partitions.相当于将分区中的数据drop掉再插入回来,对于避免磁盘碎片很有效
Example:

ALTER TABLE t1 REBUILD PARTITION p0, p1;

Optimizing partitions.如果你的表增加删除了大量数据,或者进行了大量的边长列的更新操作( VARCHAR, BLOB, or TEXT columns)。那么optimize partition将回收未使用的空间,并整理分区数据文件。
Example:

ALTER TABLE t1 OPTIMIZE PARTITION p0, p1;

运行OPTIMIZE PARTITION 相当于做了 CHECK PARTITION, ANALYZE PARTITION, and REPAIR PARTITION

Some MySQL storage engines, including InnoDB, do not support per-partition optimization; in these cases, ALTER TABLE … OPTIMIZE PARTITION rebuilds the entire table. In MySQL 5.6.9 and later, running this statement on such a table causes the entire table to rebuilt and analyzed, and an appropriate warning to be issued. (Bug #11751825, Bug #42822) Use ALTER TABLE … REBUILD PARTITION and ALTER TABLE … ANALYZE PARTITION instead, to avoid this issue.

Analyzing partitions.读取并保存分区的键分布

Example:

ALTER TABLE t1 ANALYZE PARTITION p3;

Repairing partitions.修补被破坏的分区

Example:

ALTER TABLE t1 REPAIR PARTITION p0,p1;

Checking partitions.可以使用几乎与对非分区表使用CHECK TABLE 相同的方式检查分区。

Example:

ALTER TABLE trb3 CHECK PARTITION p1;

这个命令可以告诉你表trb3的分区p1中的数据或索引是否已经被破坏。如果发生了这种情况,使用“ALTER TABLE … REPAIR PARTITION”来修补该分区。

以上每个命令都支持将分区换成ALL

The use of mysqlcheck and myisamchk is not supported with partitioned tables.

mysqlcheck和myisamchk不支持分区表

你可以使用 ALTER TABLE … TRUNCATE PARTITION. 来删除一个或多个分区中的数据
如:ALTER TABLE … TRUNCATE PARTITION ALL删除所有数据

ANALYZE, CHECK, OPTIMIZE, REBUILD, REPAIR, and TRUNCATE 操作不支持 subpartitions.

转载请注明:架构迷 » 【分享】Mysql分区表的管理与维护

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