http://www.jlcomp.demon.co.uk/faq/duplicates.html I do not know how to do an 'alter table add unique constraint' in parallel. the only way I know how to use parallel is with a 'create index'. Problem is 'exceptions into' does not seem to work with this statement. I have a big table. Anyway to use the exceptions table with the parallel clause? if not it will run for hours.