Oralce EXCHANGE PARTITION 的示例-职坐标

Oralce EXCHANGE PARTITION 的示例

诗诗 2018-03-14 来源：网络阅读 1000 评论 0

摘要：本文将讲解Oralce EXCHANGE PARTITION 知识点，看完这篇文章会让你对Oralce EXCHANGE PARTITION 的知识点有更加清晰的理解和运用。

本文将讲解Oralce EXCHANGE PARTITION 知识点，看完这篇文章会让你对Oralce EXCHANGE PARTITION 的知识点有更加清晰的理解和运用。

--创建分区表
CREATE TABLE TEST(X INT,Y INT)
PARTITION BY RANGE(X)
(
PARTITION PART0 VALUES LESS THAN (100),
PARTITION PART1 VALUES LESS THAN (MAXVALUE)
);
--创建索引
CREATE INDEX IDX_TEST_X ON TEST(X) LOCAL;
CREATE INDEX IDX_TEST_Y ON TEST(Y);

--创建交换堆表
CREATE TABLE TMP_TEST(X INT, Y INT);
--创建索引
CREATE INDEX IDX_TMP_TEST_X ON TMP_TEST(X);

--初始化分区表数据
BEGIN
FOR I IN 1..200 LOOP
INSERT INTO TEST VALUES(I,I-1);
END LOOP;
COMMIT;
END;
--初始化堆表数据
BEGIN
FOR I IN 1..50 LOOP
INSERT INTO TMP_TEST VALUES(I,I-1);
END LOOP;
COMMIT;
END;

--查看表的元数据
SQL> SELECT OBJECT_NAME,
2 SUBOBJECT_NAME,
3 OBJECT_ID,
4 DATA_OBJECT_ID,
5 OBJECT_TYPE,
6 STATUS
7 FROM DBA_OBJECTS
8 WHERE OBJECT_NAME IN ('TEST', 'TMP_TEST')
9 ORDER BY OBJECT_NAME;

OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE STATUS
-------------------- -------------------- ---------- -------------- ------------------- -------
TEST PART1 60040 60040 TABLE PARTITION VALID
TEST PART0 60039 60039 TABLE PARTITION VALID
TEST 60038 TABLE VALID
TMP_TEST 60045 60045 TABLE VALID

----索引的元数据
SQL> SELECT OBJECT_NAME,
2 SUBOBJECT_NAME,
3 OBJECT_ID,
4 DATA_OBJECT_ID,
5 OBJECT_TYPE,
6 STATUS
7 FROM DBA_OBJECTS
8 WHERE OBJECT_NAME IN ('IDX_TEST_X', 'IDX_TEST_Y','IDX_TMP_TEST_X');

OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE STATUS
-------------------- -------------------- ---------- -------------- ------------------- ------
IDX_TMP_TEST_X 60047 60047 INDEX VALID
IDX_TEST_Y 60044 60044 INDEX VALID
IDX_TEST_X 60041 INDEX VALID
IDX_TEST_X PART0 60042 60042 INDEX PARTITION VALID
IDX_TEST_X PART1 60043 60043 INDEX PARTITION VALID

--交换表及已有的索引
ALTER TABLE TEST EXCHANGE PARTITION PART0 WITH TABLE TMP_TEST INCLUDING INDEXES;

--查看数据已交换成功
SQL> SELECT COUNT(*) FROM TMP_TEST;

COUNT(*)
----------
99

SQL> SELECT COUNT(*) FROM TEST PARTITION(PART0);

COUNT(*)
----------
50
--查看表元数据的变化，可以得出结论exchange 只是交换的是数据段编号
SQL> SELECT OBJECT_NAME,
2 SUBOBJECT_NAME,
3 OBJECT_ID,
4 DATA_OBJECT_ID,
5 OBJECT_TYPE,
6 STATUS
7 FROM DBA_OBJECTS
8 WHERE OBJECT_NAME IN ('TEST', 'TMP_TEST')
9 ORDER BY OBJECT_NAME;

OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE STATUS
-------------------- -------------------- ---------- -------------- ------------------- -------
TEST PART1 60040 60040 TABLE PARTITION VALID
TEST PART0 60039 60045 TABLE PARTITION VALID
TEST 60038 TABLE VALID
TMP_TEST 60045 60039 TABLE VALID
--查看索引元数据的变化，可以看出index的变化:交换了段编号

SQL> SELECT OBJECT_NAME,
2 SUBOBJECT_NAME,
3 OBJECT_ID,
4 DATA_OBJECT_ID,
5 OBJECT_TYPE,
6 STATUS
7 FROM DBA_OBJECTS
8 WHERE OBJECT_NAME IN ('IDX_TEST_X', 'IDX_TEST_Y','IDX_TMP_TEST_X','IDX_TMP_TEST_Y');

OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID OBJECT_TYPE STATUS
-------------------- -------------------- ---------- -------------- ------------------- -------
IDX_TMP_TEST_X 60047 60042 INDEX VALID
IDX_TEST_Y 60044 60044 INDEX VALID
IDX_TEST_X 60041 INDEX VALID
IDX_TEST_X PART0 60042 60047 INDEX PARTITION VALID
IDX_TEST_X PART1 60043 60043 INDEX PARTITION VALID
--查看索引的状态
--发现分区表TEST的GLOBAL索引已不可用，需要重新创建，Local的分区索引显示为N/A，我们需要查询另外一个视图来确定是否可用
--经测试在交换分区的时候加上 update indexes 则可以避免GLobal索引失效的情况。
SQL> SELECT INDEX_NAME,TABLE_NAME,STATUS FROM DBA_INDEXES WHERE TABLE_NAME IN ('TEST','TMP_TEST');

INDEX_NAME TABLE_NAME STATUS
------------------------------ ------------------------------ --------
IDX_TEST_X TEST N/A
IDX_TEST_Y TEST UNUSABLE
IDX_TMP_TEST_X TMP_TEST VALID
--LOCAL分区索引仍然是有效的
SQL> SELECT INDEX_NAME,STATUS FROM USER_IND_PARTITIONS WHERE INDEX_NAME IN ('IDX_TEST_X');

INDEX_NAME STATUS
------------------------------ --------
IDX_TEST_X USABLE
IDX_TEST_X USABLE

一点在Oracle文档的摘抄:
//docs.oracle.com/cd/B19306_01/server.102/b14231/partiti.htm#i1107555

When you exchange partitions, logging attributes are preserved.
You can optionally specify if local indexes are also to be exchanged (INCLUDING INDEXES clause),
and if rows are to be validated for proper mapping (WITH VALIDATION clause).

Note:
When you specify WITHOUT VALIDATION for the exchange partition operation,
this is normally a fast operation because it involves only data dictionary updates.
However, if the table or partitioned table involved in the exchange operation has a primary key or unique constraint enabled,
then the exchange operation will be performed as if WITH VALIDATION were specified in order to maintain the integrity
of the constraints.

To avoid the overhead of this validation activity,
issue the following statement for each constraint before doing the exchange partition operation:

ALTER TABLE table_name
DISABLE CONSTRAINT constraint_name KEEP INDEX
Then, enable the constraints after the exchange.