How to do partitioning and sub partitioning with exchange partition in Oracle? - oracle

Question

I am facing issue with exchange partitioning and sub partitioning in Oracle.
Please explain with example.

Answer 1

Please find following example
CREATE TABLE DEPARTMENT
( DEPT_ID NUMBER(30,0) NOT NULL ENABLE,
IS_ACTIVE VARCHAR2(1 BYTE) NOT NULL ,
BUSINESS_DATE DATE NOT NULL ENABLE,
COMPANY_CODE VARCHAR2(4) DEFAULT 'C1' NOT NULL ,
CONSTRAINT PK_DEPARTMENT PRIMARY KEY (BUSINESS_DATE, COMPANY_CODE, DEPT_ID) ENABLE
)
PARTITION BY RANGE
(
BUSINESS_DATE
)
INTERVAL (
NUMTODSINTERVAL(1,'DAY')
)
SUBPARTITION BY LIST(COMPANY_CODE)
SUBPARTITION TEMPLATE
(
SUBPARTITION CMN_01 VALUES ('C1'),
SUBPARTITION CMN_02 VALUES ('C2'),
SUBPARTITION CMN_03 VALUES ('C3')
)
(
PARTITION DEFAULT_PART VALUES LESS THAN ('01-JAN-2012')
)
;
CREATE INDEX IDX1_DEPARTMENT ON DEPARTMENT (DEPT_ID, IS_ACTIVE);
CREATE TABLE TEMP_DEPARTMENT AS SELECT * FROM DEPARTMENT WHERE 1=2;
CREATE TABLE EMPLOYEE
( ID NUMBER(30,0) NOT NULL ENABLE,
DEPT_ID NUMBER(30,0) NOT NULL ENABLE,
BUSINESS_DATE DATE NOT NULL ENABLE,
COMPANY_CODE VARCHAR2(4) DEFAULT 'C1' NOT NULL,
CONSTRAINT PK_EMPLOYEE PRIMARY KEY (BUSINESS_DATE,COMPANY_CODE, ID) ENABLE,
CONSTRAINT FK1_EMPLOYEE_DEPT FOREIGN KEY (BUSINESS_DATE, COMPANY_CODE, DEPT_ID)
REFERENCES DEPARTMENT (BUSINESS_DATE, COMPANY_CODE, DEPT_ID) ENABLE NOVALIDATE
)
PARTITION BY RANGE
(
BUSINESS_DATE
)
INTERVAL (
NUMTODSINTERVAL(1,'DAY')
)
SUBPARTITION BY LIST(COMPANY_CODE)
SUBPARTITION TEMPLATE
(
SUBPARTITION CMN_01 VALUES ('C1'),
SUBPARTITION CMN_02 VALUES ('C2'),
SUBPARTITION CMN_03 VALUES ('C3')
)
(
PARTITION DEFAULT_PART VALUES LESS THAN ('01-JAN-2012')
);
Insert few thousands records into DEPARTMENT and EMPLOYEE tables for few partitions and their all sub partitions
select * from DEPARTMENT where BUSINESS_DATE='19-JAN-15' and COMPANY_CODE='C1';
select* from EMPLOYEE;
select * from all_tab_partitions where TABLE_OWNER='TEST' and
table_name='DEPARTMENT';
select * from ALL_TAB_SUBPARTITIONS where TABLE_OWNER='TEST' and
table_name='DEPARTMENT';
select * from all_tab_partitions where TABLE_OWNER='TEST' and
table_name='EMPLOYEE';
select * from ALL_TAB_SUBPARTITIONS where TABLE_OWNER='TEST' and
table_name='EMPLOYEE';
select * from TEMP_DEPARTMENT;
Exchange and Truncate sub partitions
1)Exchange sub partitioningALTER TABLE DEPARTMENT EXCHANGE SUBPARTITION SYS_SUBP7356 WITH TABLE TEMP_DEPARTMENT WITHOUT VALIDATION UPDATE GLOBAL INDEXES;
2) Truncate temp exchange table truncate table TEMP_DEPARTMENT;
3) Truncate sub partitioning (sub partition name from ALL_TAB_SUBPARTITIONS table) with global index update `ALTER TABLE DEPARTMENT TRUNCATE SUBPARTITION SYS_SUBP7356 DROP STORAGE UPDATE GLOBAL INDEXES;
Here the above 1 to 3 steps are executed for three sub-partitions
4) Get this partition name from all_tab_partitions table with global index update ALTER TABLE DEPARTMENT DROP PARTITION SYS_P7359 UPDATE GLOBAL INDEXES;
5) Truncate sub partitioning (sub partition name from ALL_TAB_SUBPARTITIONS table) with global index update ALTER TABLE EMPLOYEE TRUNCATE SUBPARTITION SYS_SUBP7360 DROP STORAGE UPDATE GLOBAL INDEXES;
Here the above 5 steps are executed for three sub-partitions
6) Get this partition name from all_tab_partitions table with global index update ALTER TABLE EMPLOYEE DROP PARTITION SYS_P7363 UPDATE GLOBAL INDEXES;
7) alter index PK_DEPARTMENT rebuild;
8) alter index IDX1_DEPARTMENT rebuild;
9) alter index PK_EMPLOYEE rebuild;
Steps 7 to 9 is require only when UPDATE GLOBAL INDEXES not used at the time of Altering Table for exchange, truncate and drop partition or sub partition
10)
begin
dbms_stats.gather_table_stats(ownname=>'TEST', tabname=>'DEPARTMENT', granularity=>'ALL' ,no_invalidate=>FALSE);
dbms_stats.gather_table_stats(ownname=>'TEST', tabname=>'EMPLOYEE', granularity=>'ALL' ,no_invalidate=>FALSE);
end;
UPDATE GLOBAL INDEXES is used at the time of Altering Table for exchange, truncate and drop partition or sub partition where global indexes are applied on that table then we can do DML operation on same table in parallel here.
UPDATE GLOBAL INDEXES is used to rebuild the indexes at same time with alter operation.
If UPDATE GLOBAL INDEXES is not used then DML operation is not allowed on same table in parallel. It will throw below ORA Exception for global indexes.
ERROR Message when perform insert operation after drop/exchange/truncate partition/sub partition from table:
SQL Error: ORA-01502: index 'TEST.PK_DEPARTMENT' or partition of such
index is in unusable state
01502. 00000 - "index '%s.%s' or partition of such index is in unusable state"
Cause: An attempt has been made to access an index or index partition that has been marked unusable by a direct load or by a DDL operation
Action: DROP the specified index, or REBUILD the specified index, or REBUILD the unusable index partition
If you don’t want to use UPDATE GLOBAL INDEXES and want parallel DML operation with purging then make indexes Local (must not contain primary key or unique constraint because it is default created global unique index). It’s on partition and sub partition and refers default table space.
With Local indexes you observed slow insertion on that table.