Hi list, I'm trying to determine how much time will be required to build a constraint - something like: ALTER TABLE <TABLE_NAME> ADD CONSTRAINT <NAME> FOREIGN KEY (<FK_NAME>) REFERENCES <REF_TABLE_NAME> (<REF_COL_NAME) ENABLE; Testing this, I don't see any operation in v$session_longops, however the test runs for hours. There are many of these and we have limited amounts of time to do them - we can do them in batches over time, however, we can't exceed our windows due to performance. I also don't see anything in v$sql_plan for this SQL_ID... How, exactly, does Oracle build a constraint? Ie, what plan/operations does it use. Is there any way I can estimate time (blocks read, etc.) prior to building the constraint? Thanks, Rich -- //www.freelists.org/webpage/oracle-l