Oracle 10g ROWNUM issue

Question

Hi --
I have the below query which takes about 30 seconds(if rownum used) on 10g and 0.2 (or less) seconds on 9i...stats are up-to-date. 10g results comes back within < 0.2 seconds if i take the rownum out from the query but the issue is when i use rownum. 9i with our with rownum comes back within <0.2 secs.
10g - takes 30 secs for this query whereas 9i takes < 0.2 secs -- WITH ROWNUM
SELECT gmdb_id, lev FROM (SELECT v.gmdb_id, v.lev FROM
(SELECT gmdb_id, parent_id, LEVEL lev, create_date
FROM NODE_TREE WHERE LEVEL = 1 AND NODE_DEF >= 2 AND node_type < 3 START WITH parent_id = 207187 CONNECT BY parent_id=PRIOR gmdb_id) v,NODE_ATTRIBUTES NAttribs WHERE NAttribs.gmdb_id = v.gmdb_id AND NVL(PUBLISH_LOCATION_ID,0) <= 0
AND DISABLED = 0 AND NVL(HIDE_FROM_PUBLISH,0) = 0 AND TO_DATE(TO_CHAR((SYSTIMESTAMP AT TIME ZONE 'GMT'),'mm/dd/yyyy HH24:MI:SS'),'mm/dd/yyyy HH24:MI:SS') BETWEEN PUBLISH_START_TIME AND PUBLISH_STOP_TIME ORDER BY sort_order DESC, v.CREATE_DATE DESC, v.gmdb_id DESC) WHERE ROWNUM < 201
---10g WITHOUT ROWNUM comes back <0.2 secs---any know issues or any suggestions as what the issue could be with and without using rownum
SELECT v.gmdb_id, v.lev FROM
(SELECT gmdb_id, parent_id, LEVEL lev, create_date FROM NODE_TREE
WHERE LEVEL = 1 AND NODE_DEF >= 2 AND node_type < 3 START WITH parent_id = 207187 CONNECT BY parent_id=PRIOR gmdb_id) v, NODE_ATTRIBUTES NAttribs WHERE NAttribs.gmdb_id = v.gmdb_id
AND NVL(PUBLISH_LOCATION_ID,0) <= 0 AND DISABLED = 0
AND NVL(HIDE_FROM_PUBLISH,0) = 0 AND TO_DATE(TO_CHAR((SYSTIMESTAMP AT TIME ZONE 'GMT'),'mm/dd/yyyy HH24:MI:SS'),'mm/dd/yyyy HH24:MI:SS') BETWEEN PUBLISH_START_TIME AND PUBLISH_STOP_TIME ORDER BY sort_order DESC, v.CREATE_DATE DESC, v.gmdb_id DESC

Answer 1

Hash join in 10g compared to nested loop in 9i.
sort(ORDER BY STOPKEY)
--10g plan cost 26470 - below is the diff in both the plans---
MAT_VIEW ACCESS(FULL) GMDB.NODE_ATTRIBUTES     ANALYZED     17767     219     7227                         NVL("PUBLISH_LOCATION_ID",0)<=0 AND NVL("HIDE_FROM_PUBLISH",0)=0 AND "PUBLISH_START_TIME"<=TO_DATE(TO_CHAR(SYSTIMESTAMP(6) AT TIME ZONE 'GMT','mm/dd/yyyy HH24:MI:SS'),'mm/dd/yyyy HH24:MI:SS') AND "PUBLISH_STOP_TIME">=TO_DATE(TO_CHAR(SYSTIMESTAMP(6) AT TIME ZONE 'GMT','mm/dd/yyyy HH24:MI:SS'),'mm/dd/yyyy HH24:MI:SS') AND "DISABLED"=0
-9i plan cost 190 - used nested loop