Reg: Order of row fetched -

Question

Hi Experts,
Scenario -
A file has data in sorted order and it is inserted into Oracle table by SQL Loader (Direct-path load enabled).
If the table is queried (without any ORDER BY clause), is there a guarantee that the ordering will be same as in the text file?
I'm quite sure it's "NO" , and has been discussed several times that - without any explicit ORDER BY clause there's no guarantee that rows will be fetched in order.
But is there any way to demonstrate this?
I tried the below workout... (but rows were always fetched in the inserted order):
CREATE TABLE table_x
AS
SELECT /*+ APPEND */ LEVEL lvl
FROM dual
CONNECT BY LEVEL <= 10
ORDER BY 1 desc;
DECLARE
    CURSOR cur_x
    IS
    SELECT lvl FROM table_x;
BEGIN
  FOR j IN 1..100
  LOOP
      FOR i IN cur_x
      LOOP
            Dbms_Output.put_line(i.lvl);
      END LOOP;
    Dbms_Output.put_line('-------LOOP '||j||'------------');
  END LOOP;
END;
Help much appreciated!
Thanks and Regards
-- Ranit

Answer 1

one example could be:
drop table t;
create table t
as
select rownum id
  from dual
connect by level <= 1000000;
select /*+ parallel(8) */ * from t where rownum < 30;
        ID
    262801
    262802
    262803
    262804
    262805
    262806
    262807
    262808
    262809
    262810
    262811
    262812
    262813
    262814
    262815
    262816
    262817
    262818
    262819
    262820
    262821
    262822
    262823
    262824
    262825
    262826
    262827
    262828
    262829
So parallel access does change the order.
I think Tom Kyte mentioned the importance of an explicit order by rather frequently (a good example is http://tkyte.blogspot.de/2005/08/order-in-court.html) - almost as frequently as he mentioned the importance of bind variables...