ah, I understand now. Joan, one last question. Have you tried then to equal the PGA size on both?... (sorry this seems so stupid, but nopw I really cannot think of other explanation aside different temp area capacity for the hash) regards. >The id=27, on TRN it retuns 0 while it returns 31,967 rows on QA is _understandable, cause on TRN it failed and it never reached that far. -- //www.freelists.org/webpage/oracle-l