Generally speaking most events set at the system level will take effect only for new sessions. It is possible to set trace (event 10046) on for an already running session. How do I switch on sql trace in another session that is already running? http://www.jlcomp.demon.co.uk/faq/alien_trace.html Oradebug has this capability. -- Mark D Powell -- Phone (313) 592-5148 -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Uwe Küchler Sent: Wednesday, May 02, 2007 1:34 PM To: oracle-l@xxxxxxxxxxxxx Subject: When do system events become effective? Oracle 9.2.0.6, HP-UX 11.11 Hello world, today I was trying to track down the SQL causing a full TEMP tablespace by tracing the 1652 event. I tried the following commands: - ALTER SYSTEM SET EVENTS '1652 trace name errorstack'; - ALTER SYSTEM SET EVENTS = '1652 trace name errorstack'; - ALTER SYSTEM SET EVENTS = '1652 trace name context forever, level 12'; - oradebug event 1652 trace name errorstack on a running system, but no trace files have been generated, although the alert log was flooded with this event after enabling trace. I had the same effect with the 10046 event a while ago and supposed that it only comes in effect when a new session is started, but then "oradebug" would be usesless in this case. This cannot be. Unfortunately (as so often) I didn't have the time to research, but now i need some input from you folks! So, why is there no tracefile after enabling trace and clearly seeing the traced event happen? Regards, Uwe -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l