Oralce EXCHANGE PARTITION 的示例

程序员文章站 2022-03-25 20:27:07

...

--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');

--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:
http://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.

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Oralce EXCHANGE PARTITION 的示例