I have some very large tables from which I have to get records NOT IN other very large tables. Code like this:

select * from table1;
where keyfield NOT IN;
(select keyfield from table2)

is not optimizable, and is extremely slow (about 15 minutes or more) for each query. I have tried a SCAN/SEEK, but it is at least as slow or worse, since you're looking for unique keys that don't exist, and therefore must hit every record.

Any ideas for something faster?