How To Change the Partition Column Of A Partitioned Table Using DBMS_Redefinition [ID 846405.1]

How To Change the Partition Column Of A Partitioned Table Using DBMS_Redefinition [ID 846405.1]
	Modified 22-OCT-2009     Type HOWTO     Status PUBLISHED

In this Document
  Goal
  Solution
  References

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Applies to:

Oracle Server - Enterprise Edition - Version: 10.2.0.4 to 11.2.0.2.0
Information in this document applies to any platform.

Goal

The purpose of this document is to provide step by step instructions on how to convert the partitioned column of an existing partitioned table to have a completely different partitioned column using dbms_redefinition package.

Solution

1) Create partitioned table (This is the table that needs to be redefined) with the name SALES.  We plan to repartition this table to use the MONTH_NO as the partitioning column.

Note:  The table already has a PK on this defined in the Create statement.

CREATE TABLE sales ( 
acct_no NUMBER(5), 
acct_name CHAR(30), 
amount_of_sale NUMBER(6), 
week_no INTEGER, 
month_no integer, 
sale_details VARCHAR2(1000), 
PRIMARY KEY (acct_no, acct_name, week_no)) 
PARTITION BY LIST (week_no) ( 
PARTITION part1234 VALUES (1, 2, 3, 4) tablespace users, 
PARTITION part5678 VALUES (5, 6, 7, 8) tablespace users, 
PARTITION partdefault VALUES (DEFAULT) tablespace users); 

insert into sales values (1,'acc 1',1,52,12,'sales details 1'); 
insert into sales values (2,'acc 2',2,51,12,'sales details 2'); 
insert into sales values (3,'acc 3',3,50,12,'sales details 3'); 
insert into sales values (4,'acc 4',4,1,1,'sales details 4'); 
insert into sales values (5,'acc 5',5,2,1,'sales details 5'); 
commit;

2) Gather statistics on the table:

EXEC DBMS_STATS.gather_table_stats('RK_MVIEW', 'SALES', cascade => TRUE);

3) Create a Partitioned Interim Table:

CREATE TABLE interim_sales ( 
     acct_no NUMBER(5), 
     acct_name CHAR(30), 
     amount_of_sale NUMBER(6),  
     week_no INTEGER, 
     month_no integer, 
     sale_details VARCHAR2(1000), 
     PRIMARY KEY (acct_no, acct_name, month_no))  
     PARTITION BY LIST (month_no) ( 
     PARTITION int_part1 VALUES (1) tablespace users, 
     PARTITION int_part12 VALUES (12) tablespace users, 
     PARTITION int_partdefault VALUES (DEFAULT) tablespace users);

4) Start the Redefinition Process: 

a) Check the redefinition is possible using the following command:

EXEC Dbms_Redefinition.can_redef_table('RK_MVIEW', 'SALES');

b)If no errors are reported, start the redefintion using the following command:

BEGIN  
DBMS_REDEFINITION.start_redef_table(  
uname => 'RK_MVIEW',   
orig_table => 'SALES',  
int_table => 'INTERIM_SALES');  
END;  
/ 

c) Optionally synchronize new table with interim name before index creation:

BEGIN  
dbms_redefinition.sync_interim_table(  
uname => 'RK_MVIEW',   
orig_table => 'SALES',  
int_table => 'INTERIM_SALES');   
END;  
/ 

d) Gather statistics on the new table:

EXEC DBMS_STATS.gather_table_stats('RK_MVIEW', 'INTERIM_SALES', cascade => TRUE); 

e) Complete the Redefintion Process:

BEGIN  
dbms_redefinition.finish_redef_table(  
uname => 'RK_MVIEW',   
orig_table => 'SALES',  
int_table => 'INTERIM_SALES');  
END;  
/ 

At this point the interim table has become the "real" table and their names have been switched in the name dictionary. 

f) Remove original table which now has the name of the interim table:

DROP TABLE INTERIM_SALES;

g) Check whether partitioning is successful or not:

SELECT partition_name 
FROM user_tab_partitions 
WHERE table_name = 'SALES';                                                                                                      

PARTITION_NAME 
------------------ 
INT_PART1 
INT_PART12 
INT_PARTDEFAULT

 

 

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