Newbie help with explain plans

Hi there,

I have a problem with a huge select statement which i run against a Oracle 9i 9.2.0.3 DB.

We have one instance in house with the same data and db version as on client side. If I run the statement in house, the statement is rather fast, if i run it at client side it is very slow.

Enclosed i send the explain plans. Could possibly someone tell where I could tune the oracle instance at client side....

Thanks in advance.

****************Slow Explain Plan

Operation Object Name Rows Bytes Cost

SELECT STATEMENT Hint=CHOOSE	 	 593  		  		 1217  		  		 
 HASH JOIN SEMI		 		 593  		 70 K		 1217  		  		  		 
    MERGE JOIN		 		 593  		 66 K		 1206  		  		  		  		 
      MERGE JOIN		 	 1 K		 101 K		 1121  		  		  		 
        SORT JOIN		 	 20 K		 589 K		 305  		  		  		 
          TABLE ACCESS FULL	 OS_A	 20 K		 589 K		 35  		 
        FILTER		 		   		  		  		  		  		  		 
          SORT JOIN		 		   		  		  		  		  		 
            TABLE ACCESS FULL	 OS_P	 21 K		 1 M		 51  		 
        SORT JOIN		 	 12 K		 154 K		 85  		  		  		 
        INDEX FAST FULL SCAN	OA_PK	 12 K		 154 K		 15  		 
    VIEW		 VW_NSO_1	 497  		 2 K		 2  		  		  		 
      CONNECT BY WITH FILTERING		 		   		  		  		 
        NESTED LOOPS		 		   		  		  		  		  		 
          INDEX UNIQUE SCAN	 O_PK     1  		 5  		 1  		 
          TABLE ACCESS BY USER ROWID	 OS_O		   		  		 
        HASH JOIN		 		   		  		  		  		  		 
          CONNECT BY PUMP		 		   		  		  		  		 
          TABLE ACCESS FULL	 OS_O     497  		 3 K		 2  		 





***********************Fast Explain

Plan*************************************

Operation	Object Name				Rows	Bytes	Cost	
SELECT STATEMENT Hint=CHOOSE				6  	 	477  	 	      	             	 
  TABLE ACCESS BY INDEX ROWID	OS_P		        20 K	1 M	2
    NESTED LOOPS					6  	678  	477  	 	      	             	 
      NESTED LOOPS					156  	6 K	165  	 	      	             	 
        NESTED LOOPS					156  	2 K	9  	 	      	             	 
          VIEW	VW_NSO_1				5  	30  	2  	 	      	             	 
            SORT UNIQUE					5  	40  	 	 	      	             	 
              CONNECT BY WITH FILTERING
                NESTED LOOPS		  	 	 	 	      	             	 
                  INDEX UNIQUE SCAN	OS_PK	        1  	5  	1
                  TABLE ACCESS BY USER ROWID	OS_O
                NESTED LOOPS		  	 	 	 	      	             	 
                  BUFFER SORT				5  	40 	 	 	      	             	 
                    CONNECT BY PUMP		  	 	 	 	      	             	 
                  TABLE ACCESS BY INDEX ROWID		5  	40  	2
                    INDEX RANGE SCAN	RO_FK	        5  	 	1
          INDEX RANGE SCAN	OS_A_PK		       31  	403  	1
        TABLE ACCESS BY INDEX ROWID	OS_A 	        1  	26  	1
          INDEX UNIQUE SCAN	A_PK		        1
      INDEX RANGE SCAN	R_A_FK			        1  	 	1