Online Table redefinition(partition maintenance) in 10g

Question

Hi,
I would like to know more about the 10g feture of online table redifinition. I am specifically looking for removing the partition or adding new partition to the the exisitng table while the sessions are accessing the table. Can you please guide me on this.
Thanks
Anand

Answer 1

I recommend you writing procedure for
appending paritions
dropping partitions
from existing partition tables.
Here is simple example of dropping partitions, remember, you should drop only when parition is no longer used by application. Similarly you can write pl/sql to append partitions
DECLARE
v_msg VARCHAR2 (200);
v_table VARCHAR2 (30);
v_partiion_cur VARCHAR2 (200);
v_sql VARCHAR2 (200);
CURSOR table_cur
IS
SELECT DISTINCT table_name
FROM user_tab_partitions
Where <your condition>= criteria;
-- reteriving partition qualified for being dropped ; pass retention period
CURSOR partition_date_cur (i_table_name IN varchar2
IS
SELECT TO_DATE (TO_NUMBER (SUBSTR (partition_name, 9, 10)),
'YYYYMMDDHH24'
partition_date,
partition_name,
tablespace_name,
table_name
FROM user_tab_partitions
WHERE table_name = i_table_name
AND TO_DATE (TO_NUMBER (SUBSTR (partition_name, 9, 10)),
'YYYYMMDDHH24'
) < (SELECT TRUNC (SYSDATE)
- (SELECT VALUE
FROM some_retention_period_conf
WHERE code = 'RETENTION_PERIOD')
FROM DUAL);
BEGIN
-- some logging message
OPEN table_cur;
FETCH table_cur INTO v_table;
CLOSE table_cur;
FOR partition_date_rec IN partition_date_cur (v_table)
LOOP
v_sql :=
'ALTER TABLE '
|| partition_date_rec.table_name
|| ' DROP PARTITION '
|| partition_date_rec.partition_name;
EXECUTE IMMEDIATE v_sql;
END LOOP;
EXCEPTION
WHEN OTHERS
THEN
v_msg :=
'Partition Removal Procedure Failed : ' || SUBSTR (SQLERRM, 1, 150);
END ;