Check the list of event traces set in Oracle current session

The following package is used to get the current event set in Oracle at the current session:

dbms_system.read_ev(iev IN  BINARY_INTEGER,oev OUT BINARY_INTEGER);
iev: event numbers 10000 to 10999
oev: default is 0 if not set otherwise returns the event level

Following is the example of the current session:

--Check the current session SID and serial#
SELECT sid, serial# FROM SYS.V_$SESSION
WHERE SID = (SELECT DISTINCT SID FROM SYS.V_$MYSTAT);
    SID    SERIAL#
---------- ----------
       223      43129

-- Set the following event 
SQL> EXEC DBMS_SYSTEM.set_ev(si=>223, se=>43129, ev=>10001, le=>8, nm=>'');
PL/SQL procedure successfully completed.
SQL> EXEC DBMS_SYSTEM.set_ev(si=>223, se=>43129, ev=>10005, le=>8, nm=>'');
PL/SQL procedure successfully completed.
SQL> EXEC DBMS_SYSTEM.set_ev(si=>223, se=>43129, ev=>10010, le=>8, nm=>'');
PL/SQL procedure successfully completed.


-- Check the Event enabled at current session with following script:
SET SERVEROUTPUT ON
DECLARE
      l_level NUMBER;
  BEGIN
      FOR l_event IN 10000..10999
      LOOP
          dbms_system.read_ev (l_event,l_level);
          IF (l_level > 0) THEN
              dbms_output.put_line ('Event '||TO_CHAR (l_event) ||
              ' is set at level '||TO_CHAR (l_level));
          END IF;
      END LOOP;
  END;
  /
Event 10001 is set at level 8
Event 10005 is set at level 8
Event 10010 is set at level 8

PL/SQL procedure successfully completed.

Disable the EVENT :

ALTER SYSTEM SET EVENTS '<event> trace name context off';