I've had similar problems in 10.2.0.2 recently with a known bug (Metalink notes 5103126, 4618615 & 5130698) causing slowness with the following recursive query: select c.name, u.name from con$ c, cdef$ cd, user$ u where c.con# = cd.con# and cd.enabled = :v1 and c.owner# = u.user# - which is executed everytime you (or your app) tries to insert a duplicate into a unique constraint and triggers ORA-00001. This can be a big problem if you have an app that tries to do this regularly. Anyway, the workaround was to delete stats on cdef$, user$ and con$ and lock them. So far, this has cleared up the problem with no known side effects. Regards, Brandon Privileged/Confidential Information may be contained in this message or attachments hereto. Please advise immediately if you or your employer do not consent to Internet email for messages of this kind. Opinions, conclusions and other information in this message that do not relate to the official business of this company shall be understood as neither given nor endorsed by it. -- http://www.freelists.org/webpage/oracle-l