sqlprofile:

we have problem query to which I ran the sql tuning advisor in grid control and generated profile with better plan and I applied to this sql id and performance was much better but now after 1 week performance is bad again and I see the drop down hash value is not using the new plan. what could be the reason for it? and Also how can I lock in the better plan ?

SELECT LEAD_ID, BUSINESS_UNIT, TREE_NAME, TERRITORY_ID, REGION_ID, DESCR50, BO_ID_SITE, CUST_SETID, PRODUCT_ID, PROD_SETID, FULFILL_SETID, NAME1, FIRST_NAME, LAST_NAME, OPPORTUNITY_ID, LEAD_SOURCE_ID, BUSINESS_UNIT_RA, RA_CAMPAIGN_ID, RA_CMPGN_WAVE_ID, LEAD_RATING, LEAD_TYPE, LEAD_STATUS, INDUSTRY_ID, EST_REVENUE, PERSON_ID, BO_ID_PERSON, SALES_USER_NAME, CURRENCY_CD, CHNL_PARTNER_ID, ALLIANC_PARTNER_ID, TO_CHAR(REFERRED_DT,