RULE HINT 11.2

Question

Version Details
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE 11.2.0.3.0 Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
I have inherited this code in a package and was looking at the explain plan contains a Hint that is RULE , the database is 11.2 is it still valid, can anyone give me some advice on how to improve the below query?
| Id  | Operation                        | Name                       |
|   0 | SELECT STATEMENT                 |                            |
|   1 |  SORT AGGREGATE                  |                            |
|*  2 |   INDEX RANGE SCAN               | PARCEL_HISTORY_HOLDING_PF1 |
|   3 |  NESTED LOOPS OUTER              |                            |
|   4 |   NESTED LOOPS OUTER             |                            |
|   5 |    NESTED LOOPS OUTER            |                            |
|*  6 |     FILTER                       |                            |
|   7 |      NESTED LOOPS OUTER          |                            |
|   8 |       TABLE ACCESS BY INDEX ROWID| PARCEL_HISTORY_HOLDING     |
|   9 |        INDEX FULL SCAN           | PARCEL_HISTORY_HOLDING_PF1 |
|  10 |       TABLE ACCESS BY INDEX ROWID| PARCELS                    |
|* 11 |        INDEX UNIQUE SCAN         | PARCELS_PK                 |
|  12 |     TABLE ACCESS BY INDEX ROWID  | PARCEL_ADDRESSES           |
|* 13 |      INDEX UNIQUE SCAN           | PARCEL_ADDRESSES_PK        |
|  14 |    TABLE ACCESS BY INDEX ROWID   | PARCEL_ADDRESSES           |
|* 15 |     INDEX UNIQUE SCAN            | PARCEL_ADDRESSES_PK        |
|* 16 |   INDEX UNIQUE SCAN              | PARCEL_HISTORY_PIVOT_PK    |
Predicate Information (identified by operation id):
   2 - access("PH"."PARCEL_ID"=:B1)
   6 - filter("P"."PARCEL_ID" IS NOT NULL)
  11 - access("PHH"."PARCEL_ID"="P"."PARCEL_ID"(+))
  13 - access("PAC"."PARCEL_ID"(+)="P"."PARCEL_ID" AND
              "PAC"."ADDRESS_TYPE"(+)='COL')
  15 - access("PAD"."PARCEL_ID"(+)="P"."PARCEL_ID" AND
              "PAD"."ADDRESS_TYPE"(+)='DEL')
  16 - access("PHH"."PARCEL_ID"="PP"."PARCEL_ID"(+))
Note
   - rule based optimizer used (consider using cbo)
QUERY
     SELECT   /*+ rule */
                     phh.ROWID tabrow
                    ,phh.parcel_id
                    ,phh.scan_date
                    ,phh.status_code
                    ,phh.reason_code
                    ,phh.app_code
                    ,phh.scan_id
                    ,phh.location_code
                    ,phh.card_id
                    ,phh.signature_captured
                    ,phh.signature_reference
                    ,phh.geo_latitude
                    ,phh.geo_longitude
                    ,phh.geo_date
                    ,phh.geo_signal_strength
                    ,phh.app_create_date
                    ,phh.e2e_create_date
                    ,phh.driver_comments
                    ,p.client_account
                    ,p.client_contract
                    ,p.courier_type
                    ,p.service_code
                    ,p.col_depot
                    ,p.col_tour
                    ,p.del_depot
                    ,p.del_tour
                    ,p.traffic_type
                    ,p.signature_reqd
                    ,p.nom_del_date
                    ,p.exp_del_channel
                    ,p.exp_del_tour
                    ,p.exp_del_date
                    ,p.exp_col_tour
                    ,p.exp_col_date
                    ,pad.geo_latitude del_geo_latitude
                    ,pad.geo_longitude del_geo_longitude
                    ,pad.post_code delivery_postcode
                    ,pac.post_code collection_postcode
                    ,CASE
                         WHEN phh.scan_date =
                                           (SELECT MIN (scan_date)
                                              FROM parcel_history_holding ph
                                             WHERE ph.parcel_id = phh.parcel_id)
                         AND pp.parcel_id IS NULL THEN 1
                         ELSE 0
                     END not_in_pp_insert_flag
                    ,get_tt_status (app_code, status_code || reason_code)
                                                                      tt_status_reason
            FROM     parcel_history_holding phh
                    ,parcel_history_pivot pp
                    ,parcels p
                    ,parcel_addresses pad
                    ,parcel_addresses pac
               WHERE phh.parcel_id = pp.parcel_id(+)
                 AND phh.parcel_id = p.parcel_id(+)
                 AND pad.parcel_id(+) = p.parcel_id
                 AND pad.address_type(+) = 'DEL'
                 AND pac.parcel_id(+) = p.parcel_id
                 AND pac.address_type(+) = 'COL'
               --  AND p_thread = pkg_utils.get_thread (phh.parcel_id, v_num_threads)
                 AND p.parcel_id IS NOT NULL
            ORDER BY phh.parcel_id
                    ,phh.scan_date;

Answer 1

As Manik shows with the documentation link, the RULE hint was deprecated ages ago, especially with the CBO becoming the prominent optimizer in 10g.
And as oracle no longer support Rule based optimization, you could end up with odd 'side effects' if you use it.
Optimizer hints are something you shouldn't really be using in production code anyway...
Comments
Hints were introduced in Oracle7, when users had little recourse if the optimizer generated suboptimal plans. Now Oracle provides a number of tools, including the SQL Tuning Advisor, SQL plan management, and SQL Performance Analyzer, to help you address performance problems that are not solved by the optimizer. Oracle strongly recommends that you use those tools rather than hints. The tools are far superior to hints, because when used on an ongoing basis, they provide fresh solutions as your data and database environment change.
Hints should be used sparingly, and only after you have collected statistics on the relevant tables and evaluated the optimizer plan without hints using the EXPLAIN PLAN statement. Changing database conditions as well as query performance enhancements in subsequent releases can have significant impact on how hints in your code affect performance.
(my highlight)