内连接性能

Question

SQL语句：

SELECT /*+ PARALLEL(A,10)*/
    B.USER_ID, B.ACCT_ID, ITEM_ID, SUMFEE_C, SUMFEE_P, 
    USER_BEGIN_DATE, USER_END_DATE
FROM   
    TS_B_USER_RATEFEE_03 A, DH_ROUTE_6_OPTIONAL PARTITION(PAR_DH_ROUTE6_4) B
WHERE  
    A.USER_ID = B.USER_ID
ORDER BY 
    B.ACCT_ID, B.USER_ID;

表A的索引为user_id

如何使用同一列提高内部联接性能？