slow deletes

[Raj]

We have a batch process that deletes about 1 million records every day
&takes about 30-35 mins to complete. Is there a way to optimize
deletes? Below is the statement

delete from fact where (key,dt) in (select key,dt from dim1 union
select key,dt from dim2)

Fact table has composite index on key,someothecolumn,dt.

>From the access plan, i see that the index is being used.

Can we implement parallel deletes or tune any other db paramaeter ? We
are on db2 udb v8.2 DPF on 10 logical nodes.
Thanks
Raj