SQL & PL/SQL

Hi Friends,

I have two tables with following data.

CS_DS_DETAIL : 15.8 Million Rows
SALES_DATA : 28.05 Millions Rows

When I execute the following MERGE statement it completed only 1% after 8 hours.

SQL> explain plan for
  2  MERGE /*+ INDEX(dtl cs_ds_detail_pk,sd sales_data_pk) */ INTO sales_data sd
  3        USING cs_ds_detail dtl
  4        ON (    sd.item_id = dtl.item_id
  5            AND sd.location_id = dtl.location_id
  6            AND sd.sales_date = dtl.week_end_date)
  7        WHEN MATCHED THEN
  8           UPDATE
  9              SET sd.cs_turn_ord = dtl.turn_plug_adj, sd.cs_promo_ord = dtl.promo_plug;

Explained.

SQL> SELECT * 
  2  FROM   TABLE(DBMS_XPLAN.DISPLAY);

PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------
Plan hash value: 3300673510

----------------------------------------------------------------------------------------------------
| Id  | Operation                      | Name            | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     |
----------------------------------------------------------------------------------------------------
|   0 | MERGE STATEMENT                |                 |    15M|   457M|       |  2615K  (2)| 08:43:12 |
|   1 |  MERGE                         | SALES_DATA      |       |       |       |            |          |
|   2 |   VIEW                         |                 |       |       |       |            |          |
|*  3 |    HASH JOIN                   |                 |    15M|  4279M|   897M|  2615K  (2)| 08:43:12 |
|   4 |     TABLE ACCESS BY INDEX ROWID| CS_DS_DETAIL    |    15M|   723M|       |  1319K  (1)| 04:23:52 |
|   5 |      INDEX FULL SCAN           | CS_DS_DETAIL_PK |    15M|       |       | 80488   (1)| 00:16:06 |

PLAN_TABLE_OUTPUT
----------------------------------------------------------------------------------------------------
|   6 |     TABLE ACCESS FULL          | SALES_DATA      |    26M|  6178M|       |   929K  (4)| 03:05:56 |
----------------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   3 - access("SD"."ITEM_ID"="DTL"."ITEM_ID" AND "SD"."LOCATION_ID"="DTL"."LOCATION_ID" AND
              "SD"."SALES_DATE"="DTL"."WEEK_END_DATE")

How can I make it work better. It is a straight forward Merge statement and we are using Oracle 11g.
Both the tables are not partitioned.

Is there a way I can write this using simple Update rather using Merge?
Does anyone think Update has better performance than Merge in this case ?

Thanks guys for your time.

~Raj