DELETE statement performance issue

Question

Dear all,
I ahve the following problem:
When running the delete script bellow:
DELETE FROM aux_exist_relationship_3 aer_3
WHERE EXISTS (SELECT ''
FROM aux_kind_of_control_1 akc_1
WHERE aer_3.cons_rel_id_new= akc_1.cons_rel_id)
AND NOT EXISTS (SELECT ''
FROM aux_kind_of_control_3 akc_3
WHERE akc_3.cons_rel_id=aer_3.cons_rel_id_new)
it takes more than 50 mins to excute it, despite there are indexes on the 3 used tables, on the three fields akc_1.cons_rel_id,akc_3.cons_rel_id and aer_3.cons_rel_id_new
Can someone advise me how to solve the issue?

Answer 1

How many rows do you expect to delete?
You can tryDELETE FROM aux_exist_relationship_3 aer_3
      WHERE aer_3.cons_rel_id_new IN(SELECT akc_1.cons_rel_id
                                       FROM aux_kind_of_control_1 akc_1
                                     MINUS
                                     SELECT akc_3.cons_rel_id
                                       FROM aux_kind_of_control_3 akc_3)Urs