MySQL分区表管理
RANGE,LIST分区管理1:为未分区表创建分区
ALTER TABLE trb3 PARTITION BY KEY(id) PARTITIONS 2;
2:删除某个分区的数据
ALTER TABLE tr DROP PARTITION p2;
3:为分区表添加一个分区
ALTER TABLE members ADD PARTITION (PARTITION p3 VALUES LESS THAN (2000));
ALTER TABLE tt ADD PARTITION (PARTITION p2 VALUES IN (7, 14, 21));
ALTER TABLE employees ADD PARTITION (
PARTITION p5 VALUES LESS THAN (2010),
PARTITION p6 VALUES LESS THAN MAXVALUE
);
4:将分区表的第一个分区分为两个新的分区
ALTER TABLE members
REORGANIZE PARTITION p0 INTO (
PARTITION n0 VALUES LESS THAN (1960),
PARTITION n1 VALUES LESS THAN (1970)
);
5:也可以将两个分区合并为一个分区,也可以理解为重新组织分区
ALTER TABLE members REORGANIZE PARTITION s0,s1 INTO (
PARTITION p0 VALUES LESS THAN (1970)
);
ALTER TABLE tbl_name
REORGANIZE PARTITION partition_list
INTO (partition_definitions);
ALTER TABLE members REORGANIZE PARTITION p0,p1,p2,p3 INTO (
PARTITION m0 VALUES LESS THAN (1980),
PARTITION m1 VALUES LESS THAN (2000)
);
ALTER TABLE tt ADD PARTITION (PARTITION np VALUES IN (4, 8));
ALTER TABLE tt REORGANIZE PARTITION p1,np INTO (
PARTITION p1 VALUES IN (6, 18),
PARTITION np VALUES in (4, 8, 12)
);
删除分区表：alter table tb_user remove partitioning;
HASH,KEY 分区管理
1:创建一个hash分区表
CREATE TABLE clients (
id INT,
fname VARCHAR(30),
lname VARCHAR(30),
signed DATE
)
PARTITION BY HASH( MONTH(signed) )
PARTITIONS 12;
将分区表从12个分区变为8个分区
ALTER TABLE clients COALESCE PARTITION 4;
同样的有以下的语句关于KEY分区的表:
mysql> CREATE TABLE clients_lk (
-> id INT,
-> fname VARCHAR(30),
-> lname VARCHAR(30),
-> signed DATE
-> )
-> PARTITION BY LINEAR KEY(signed)
-> PARTITIONS 12;
Query OK, 0 rows affected (0.03 sec)
mysql> ALTER TABLE clients_lk COALESCE PARTITION 4;
Query OK, 0 rows affected (0.06 sec)
Records: 0Duplicates: 0Warnings: 0
当然还有有限制的
mysql> ALTER TABLE clients COALESCE PARTITION 18;
ERROR 1478 (HY000): Cannot remove all partitions, use DROP TABLE instead
要是分区数比现有的分区数多的话,只能使用 ADD来添加分区数.下面就表示增加了6个分区数
ALTER TABLE clients ADD PARTITION PARTITIONS 6;
交换分区,子分区的管理 交换分区,ALTER TABLE pt EXCHANGE PARTITION p WITH TABLE nt
where pt is the partitioned table and p is the partition or subpartition of pt to be exchanged with unpartitioned table nt, provided that the following statements are true:
要满足以下的条件:
1:PT是已经分区表,nt不是临时表
2:两张表的表结构必须是一模一样的
3:nt不能有外键约束,也不能有关于其他表的外键约束.
4:nt表中的数据没有分区P以外的数据.WITHOUT VALIDATION指定的时候这条就可以忽视调
另外很重要的一点就是想要拥有EXCHANGE的权限的话必须对全表有DROP的权限才可以执行.
alter table......EXCHANGE partition将不会调用任何的触发器,执行完以后被EXCHANGE 的表的自增列就会重新赋初始值.
例如:
ALTER TABLE pt
EXCHANGE PARTITION p
WITH TABLE nt with VALIDATION ;
1:将分区和一个没有分区的表EXCHANGE
创建表插入语句:
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");
查看分区和分区的行数
SELECT PARTITION_NAME, TABLE_ROWS
FROM INFORMATION_SCHEMA.PARTITIONS
WHERE TABLE_NAME = 'e';
SELECT TABLE_NAME, PARTITION_NAME, TABLE_ROWS, AVG_ROW_LENGTH, DATA_LENGTH FROM INFORMATION_SCHEMA.PARTITIONS WHERE TABLE_SCHEMA = 'p' AND TABLE_NAME LIKE 'e';
创建新表:
CREATE TABLE e2 LIKE e;
然后交换分区开始了:
ALTER TABLE e EXCHANGE PARTITION p0 WITH TABLE e2;
这个语句是很奇怪的,如果e2里面没有数据的话就是切出分区,如果e2里面有数据的话就是相互交换
但是如果e2里面的数据不能够满足分区p0的要求的话,切分区就会失败.
1737 - Found a row that does not match the partition
只有再指定不验证的时候才不会报错
ALTER TABLE e EXCHANGE PARTITION p0 WITH TABLE e2 WITHOUT VALIDATION;
WITHOUT VALIDATION 指定的时候效率会更高,因为不再做逐行验证了.
子分区和没分区的表进行切换
1:假设创建一个分区表,带有子分区
> 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)
-> );
然后就可以切分区了,先查看一下分区,
SELECT PARTITION_NAME, SUBPARTITION_NAME, TABLE_ROWS
FROM INFORMATION_SCHEMA.PARTITIONS
WHERE TABLE_NAME = 'es';
然后切出分区:
ALTER TABLE es EXCHANGE PARTITION p3sp0 WITH TABLE es2;
当前执行切出分区前,必须要对新表做以下的处理:
ALTER TABLE es2 REMOVE PARTITIONING;
修改表的默认引擎:
ALTER TABLE es3 ENGINE = MyISAM;
维护表分区
1:重建分区
ALTER TABLE t1 REBUILD PARTITION p0, p1;
2:重新组织分区
ALTER TABLE t1 OPTIMIZE PARTITION p0, p1;
3:分析某个分区,主要看行数和名称以及状态
ALTER TABLE t1 ANALYZE PARTITION p3;
4:修复分区,有重复值的时候就会报错.
ALTER TABLE t1 REPAIR PARTITION p0,p1;
5:检查分区的状态
ALTER TABLE trb3 CHECK PARTITION p1;
6:truncate分区
ALTER TABLE ... TRUNCATE PARTITION.
ALTER TABLE ... TRUNCATE PARTITION ALL
7:获取表的信息
Using the SHOW CREATE TABLE statement to view the partitioning clauses used in creating a partitioned table.
Using the SHOW TABLE STATUS statement to determine whether a table is partitioned.
Querying the INFORMATION_SCHEMA.PARTITIONS table.
Using the statement EXPLAIN PARTITIONS SELECT to see which partitions are used by a given SELECT.
看以下信息:
mysql> EXPLAIN PARTITIONS SELECT * FROM trb1\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: trb1
partitions: p0,p1,p2,p3
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 10
Extra: Using filesort
分区的经典案例:
mysql> CREATE TABLE employees_sub(
-> id INT NOT NULL AUTO_INCREMENT,
-> fname VARCHAR(25) NOT NULL,
-> lname VARCHAR(25) NOT NULL,
-> store_id INT NOT NULL,
-> department_id INT NOT NULL,
-> PRIMARY KEY pk (id, lname)
-> )
-> PARTITION BY RANGE(id)
-> SUBPARTITION BY KEY (lname)
-> SUBPARTITIONS 2 (
-> PARTITION p0 VALUES LESS THAN (5),
-> PARTITION p1 VALUES LESS THAN (10),
-> PARTITION p2 VALUES LESS THAN (15),
-> PARTITION p3 VALUES LESS THAN MAXVALUE
-> );
分区的一些添删查修语句:
mysql> DELETE FROM employees PARTITION (p0, p1)
-> WHERE fname LIKE 'j%';
Query OK, 2 rows affected (0.09 sec)
mysql> UPDATE employees PARTITION (p2)
-> SET store_id = 2 WHERE fname = 'Jill';
SELECT * FROM employees PARTITION (p2);
mysql> INSERT INTO employees PARTITION (p2) VALUES (20, 'Jan', 'Jones', 1, 3);ERROR 1729 (HY000): Found a row not matching the given partition set
mysql> INSERT INTO employees PARTITION (p3) VALUES (20, 'Jan', 'Jones', 1, 3);
Query OK, 1 row affected (0.07 sec)
分区不够多,要添加分区:
ysql> ALTER TABLE employees
-> REORGANIZE PARTITION p3 INTO (
-> PARTITION p3 VALUES LESS THAN (20),
-> PARTITION p4 VALUES LESS THAN (25),
-> PARTITION p5 VALUES LESS THAN MAXVALUE
-> );
Query OK, 6 rows affected (2.09 sec)
Records: 6Duplicates: 0Warnings: 0
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