UL stands for 'User-defined Lock'. Obviously some of your sessions are waiting because of user locks. See DBMS_LOCK package. Regards, Joze ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Dean Richards Sent: 11. junij 2007 18:31 To: oracle-l@xxxxxxxxxxxxx Subject: enq: UL - contention Wait Event Does anyone know what the wait event named "enq: UL - contention" means? There is nothing in Metalink or anywhere that I can find that gives the definition. I have a session that waits more than 90% of its time on this event. Thanks.