Update..improve performance

Question

Hell friends,
In a procedure UPDATE statement took more than 20-30 min to update 200,000 records.
Tables contains almost 2,000,000 records. As per functionality we need to set 0 value to almost 200,000 records.
Is there any way round to increase performance of this update statement.
UPDATE sales_det
SET res_qty = 0,
     ord_qty = 0,
     hold_qty = 0
WHERE period >= l_curr_period
AND itemno IN (SELECT itemno
     FROM xxitems
     WHERE ( comp_id = p_comp_id
          OR p_comp_id = 0
     );

Answer 1

Try change the update to:
UPDATE sales_det
SET res_qty = 0,
ord_qty = 0,
hold_qty = 0
WHERE period >= l_curr_period
AND exists (SELECT null
FROM xxitems
WHERE sales_det.itemno=xxitems.itemno and ( comp_id = p_comp_id
OR p_comp_id = 0
Check if xxitems table have index on itemno and comp_id column
And please post the explain plan.
Regards
Helio Dias
http://heliodias.com