Help with "alter system set events = '1000 trace name ERRORSTACK level 3'"

Question

Hello.
I am trying to find out wich sql code is creating the error ORA-01000 in my application (database release is 9.2.0.7). I have read this http://www.orafaq.com/node/758 and there they suggest doing this:
Sometimes you will need to get a full stack trace of the problem by setting a trace for ORA-1000 as in:
alter system set events = '1000 trace name ERRORSTACK level 3'
or...
alter session set events = '1000 trace name ERRORSTACK level 3'
Then set open_cursors to a low enough number to catch the open cursor voilator in your net.I have no idea about this traces, so these are my questions:
1. Do those commands force a trace every time the ORA-01000 errors rises in every session? (I have forced the ORA-01000 error in one sqplusl session after I wrote "alter session set events = '1000 trace name ERRORSTACK level 3'" in another sqlplus session)
2. What does level 3 mean?
3. I see that in the dump/user directory I have several trace files, how can I know which error traces are enabled in my db?
4. How do I disable the traces once I find out to solve the problem?
5. How do I identify in the traces the ORA-1000 error?
Thanks in advance.

Answer 1

Thanks for all the answers.
What am I doing bad? I have tried ti find out what traces are enabled, and there seems to be none.
SQL> r
  1  DECLARE
  2     OUT   BINARY_INTEGER;
  3  BEGIN
  4     DBMS_OUTPUT.put_line ('Init');
  5
  6     FOR i IN 1 .. 20000
  7     LOOP
  8        SYS.DBMS_SYSTEM.read_ev (i, OUT);
  9
10        IF (OUT <> 0)
11        THEN
12           DBMS_OUTPUT.put_line ('i: ' || i || '; ' || OUT);
13        END IF;
14     END LOOP;
15
16     DBMS_OUTPUT.put_line ('End');
17* END;
Init
EndBut, otherwise, there are trc files which have been modfiied recently? I seems as if this procedure can't detect all the tracles enabled:
(oracle)mano1re(principal)$ ls -lt *.trc | more
-rw-r-----   1 oracle   dba       348294 jul 14 18:35 reflex_ora_11706.trc
-rw-r-----   1 oracle   dba       997820 jul  9 16:32 reflex_ora_15766.trc
-rw-r-----   1 oracle   dba       399571 jul  3 15:23 reflex_ora_25955.trc
-rw-r-----   1 oracle   dba      1637069 jun  9 15:34 reflex_ora_19742.trc
PL/SQL procedure successfully completed.