Delete Statement taking long time

Question

Can anyone help for the below query:
DELETE FROM apm_prod_mst_interface
     WHERE plant_code= 'CAPL'
AND trunc(start_date) = '20-FEB-2008'
AND shift = p_mb_details.shift
AND formula_class = p_mb_details.formula_class
AND item_no = p_batch_details.item_no
AND line_no = p_mb_details.line_no
AND nvl(formula_no,'1') = NVL('ASCC1','1')
AND nvl(formula_vers,-1) = NVL(13,-1)
AND uom = 'KG'
AND NVL(routing_no,'-1') = NVL('SFSDF-2','-1')
AND NVL(routing_vers,0) = NVL(14,0)
AND NVL(plan_start_date,trunc(sysdate)) = NVL('20-FEB-2008',trunc(sysdate))
AND NVL(expct_cmplt_date,trunc(sysdate)) = NVL('20-FEB-2008',trunc(sysdate))
AND user_name = 'DUMMY'
AND schedule = 2
AND plan_qty > 0;
Regards

Answer 1

Check the High Water Mark of the table!
If the table has lots of inserts & deletes all the time, the HWM may be 1000 miles away from the actual data (But Orcale will need to read all the blocks to determine if they are empty).
Has the table been analyzed recently?
Explain plan for the equivalent SELECT?
IF you have index'es on all the fields, then an update will take time, since it has to update 15-20 indexes.
I would:
1) Try to time just the SELECT (explain plan & autotrace)
2) Gather stats
3) SELECT again - and see if difference?
4) If not -> ALTER TABLE <name> MOVE (to fix HWM)
5) SELECT again
best regards
Mette