How do you determine a process or sessions isolation level.

Question

We are using COM+ components to issue database statements against an Oracle 8i database. COM+ has a property that allows you to set the isolation level. Is there any tool or query that would allow me to verify the isolation level in use by a session or process? I want to verify this property is actually affecting the connection to the DB.
Thanks,
Sam

Answer 1

FLAG is just one of those columns that Oracle uses. It isn't documented but, as far as I know (which isn't very far), the only use for it is to record the isolation level for the transaction.
I didn't mention it because I didn't think it helped you, for this reason: we don't get a record in the v$transaction view until the transaction has already started. At which point it is too late to change the ISOLATION_LEVEL for the transaction.
Although I suppose you could do this:
BEGIN
   UPDATE dummy_table set col1 = col1;
   -- remember V$TRANSACTION shows all txns
   SELECT count(1) INTO ln
   FROM   v$transaction t, v$session s
   WHERE  bitand(t.flag,268435456) <> 0
   AND    s.taddr = t.addr
   AND    s.audsid = sys_context('userenv', 'sessionid');
   IF ln = 0
   THEN
      ROLLBACK;
      SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
   END IF;
   --  do_whatever
   COMMIT;
END ;.
Cheers, APC