Oracle表分区合并

在看一篇介绍表分区的文章时，产生了一个疑问，如何表的分区处于不同表空间，那么合并后的分区是属于哪个表空间的？

下面进行实验：

实验1：

创建不同表空间的hash分区

SQL> CREATE TABLE HASH_TABLE 

  2  ( 

  3    COL NUMBER(8), 

  4    INF VARCHAR2(100) 

  5  ) 

  6  PARTITION BY HASH (COL) 

  7  ( PARTITION PART01 TABLESPACE users,

  8  PARTITION PART02 TABLESPACE test)

  9  ;

SQL> select PARTITION_NAME,PARTITION_POSITION, TABLESPACE_NAME from USER_TAB_PARTITIONS where table_name='HASH_TABLE';

PARTITION_NAME                 PARTITION_POSITION TABLESPACE_NAME

------------------------------ ------------------ ------------------------------

PART01                                          1 USERS

PART02                                          2 TEST

SQL>ALTER TABLE HASH_TABLE  MERGE PARTITIONS PART01,PART02 INTO PARTITION PART02;

SQL> ALTER TABLE HASH_TABLE  MERGE PARTITIONS PART01,PART02 INTO PARTITION PART02;

ALTER TABLE HASH_TABLE  MERGE PARTITIONS PART01,PART02 INTO PARTITION PART02

            *

ERROR at line 1:

ORA-14255: table is not partitioned by Range, List, Composite Range or

Composite List method

结论：hash分区表不能进行合并。

实验2：

创建不同表空间的范围分区

CREATE TABLE CUSTOMER 

( 

    CUSTOMER_ID NUMBER NOT NULL PRIMARY KEY

)

PARTITION BY RANGE (CUSTOMER_ID) 

( 

    PARTITION CUS_PART1 VALUES LESS THAN (10) TABLESPACE users, 

    PARTITION CUS_PART2 VALUES LESS THAN (20) TABLESPACE test 

);

SQL> select PARTITION_NAME,PARTITION_POSITION, TABLESPACE_NAME from USER_TAB_PARTITIONS where table_name='CUSTOMER';

PARTITION_NAME                 PARTITION_POSITION TABLESPACE_NAME

------------------------------ ------------------ ------------------------------

CUS_PART1                                       1 USERS

CUS_PART2                                       2 TEST

SQL> ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART2 INTO PARTITION CUS_PART1;

ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART2 INTO PARTITION CUS_PART1

                                       *

ERROR at line 1:

ORA-14275: cannot reuse lower-bound partition as resulting partition

结论1：分区不能向小范围的分区合并，只能向大范围合并

SQL>ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART2 INTO PARTITION CUS_PART2;

SQL> select PARTITION_NAME,PARTITION_POSITION, TABLESPACE_NAME from USER_TAB_PARTITIONS where  table_name='CUSTOMER';

PARTITION_NAME                 PARTITION_POSITION TABLESPACE_NAME

------------------------------ ------------------ ------------------------------

CUS_PART2                                       1 SYSTEM

结论2：未指定表空间分区合并后，生成的分区表空间为用户默认表空间

SQL> ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART2 INTO PARTITION CUS_PART2 tablespace users;

SQL> select PARTITION_NAME,PARTITION_POSITION, TABLESPACE_NAME from USER_TAB_PARTITIONS where  table_name='CUSTOMER';

PARTITION_NAME                 PARTITION_POSITION TABLESPACE_NAME

------------------------------ ------------------ ------------------------------
CUS_PART2                                       1 USERS

结论3：通过语句修改为合并后的分区指定表空间

实验3：

测试非相邻分区是否可以合并

SQL> CREATE TABLE CUSTOMER 

  2  ( 

  3      CUSTOMER_ID NUMBER NOT NULL PRIMARY KEY

  4  )

  5  PARTITION BY RANGE (CUSTOMER_ID) 

  6  ( 

  7      PARTITION CUS_PART1 VALUES LESS THAN (10) TABLESPACE users, 

  8      PARTITION CUS_PART2 VALUES LESS THAN (20) TABLESPACE test ，

  9      PARTITION CUS_PART3 VALUES LESS THAN (30) TABLESPACE test

 10  );

Table created.

SQL>  select PARTITION_NAME,PARTITION_POSITION, TABLESPACE_NAME from USER_TAB_PARTITIONS where table_name='CUSTOMER';

PARTITION_NAME                 PARTITION_POSITION TABLESPACE_NAME

------------------------------ ------------------ ------------------------------

CUS_PART1                                       1 USERS

CUS_PART2                                       2 TEST

CUS_PART3                                       3 TEST

SQL>  ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART3 INTO PARTITION CUS_PART3 tablespace users;

 ALTER TABLE CUSTOMER  MERGE PARTITIONS CUS_PART1,CUS_PART3 INTO PARTITION CUS_PART3 tablespace users

                                        *

ERROR at line 1:

ORA-14274: partitions being merged are not adjacent

结论：非相邻表分区不能进行合并