Need suggestion in deletion for five tables at a time

Question

Hi,
I need some suggestion regarding a deletion and i have the following scenario.
tab1 contains 100 items.
for one item tab2..6 tables contain 4000 rows.So the loop will run for each item and will delete 20,000 lines and will do a commit.
Currently for 5,00,000 deletion it is taking 1 hr.All the tables and indexes are analysied.
CURSOR C_CHECK_DELETE_IND
IS
SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y';
type p_item IS TABLE OF tab1.item%type;
act_p_item p_item;
BEGIN
OPEN C_CHECK_DELETE_IND;
LOOP
FETCH C_CHECK_DELETE_IND bulk collect INTO act_p_item limit 5000;
FOR i IN 1..act_p_item.count
LOOP
DELETE FROM tab2 WHERE item = act_p_item(i);
DELETE FROM tab3 WHERE item = act_p_item(i);
DELETE FROM tab4 WHERE item = act_p_item(i);
DELETE FROM tab5 WHERE item = act_p_item(i);
DELETE FROM tab6 WHERE item = act_p_item(i);
COMMIT;
END IF;
END LOOP;
exit when C_CHECK_DELETE_IND%notfound;
END LOOP;
Hope i have explained the scenario.Can you please suggest me the right approach.
Thanks in advance.

Answer 1

drop the loop
DELETE FROM tab2 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' );
DELETE FROM tab3 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' );
DELETE FROM tab4 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' );
DELETE FROM tab5 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' );
DELETE FROM tab6 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' );if you can accomplish the task without looping, by all means do so!
you could also do a bulk delete.
forall j in indices of act_p_item save exceptions
  DELETE tab2
   WHERE item = act_p_item(j);etc for tab3 to 6
but unless the query SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' is horrible, I'd stick to the
DELETE FROM tab2 WHERE item in (SELECT api.item FROM tab1 api WHERE api.delete_item_ind = 'Y' ); path
Edited by: tanging on Dec 21, 2009 10:19 AM