Hi, Depends on what you want to do. If you want to get an error stack trace at detail level 3 once when this error happens (per session) then you can use what you mentioned: alter system set events '3120 trace name errorstack level 3'; This would dump errorstack only on the first occurrance of that error in the session. Subsequent errors in that session will not cause a stack dump. You can use this to make a session always dump errors stack on that error: alter session set events '3120 trace name errorstack level 3, forever'; Or if you want to dump the errorstack on let say first 42 ocurrences in that session, you can use lifetime option instead of forever: alter session set events '3120 trace name errorstack level 3, lifetime 42'; The second command you mentioned would dump context specific trace information for that event number. Not all event numbers have context specific tracing available. And I haven't seen any events in the error code range which would have context specific trace so I think it wouldn't help you. -- Tanel Poder http://blog.tanelpoder.com _____ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ethan Post Sent: 12 February 2009 12:54 To: oracle-l Subject: trace name ERRORSTACK vs. trace name context forever Got a client getting 3120 errors. Oracle advised them to set alter system set events '3120 trace name ERRORSTACK level 3' Which I am familiar with. However then they came back and told them to set the same event minus the ERRORSTACK keyword. alter system set events '3120 trace name context forever, level 3' What is the difference? They are not getting any dumps when the latter is set even though the error is occurring?