How to fetch data only from index

Question

Hi,
I'm using below query which fetches arount 1,00,000 records & then perform group operations on them.
<pre>
SELECT Record_Type,Country_Product_Id,Channel_Id,SUM(Items)
FROM t_Utr
WHERE Four_Eyes_Status='A'
AND(
Booking_Date >= To_Date(v_Period_Start_Date, 'DD/MM/YYYY')
AND Booking_Date <= To_Date(v_Period_End_Date , 'DD/MM/YYYY')
AND Invoice_Id IS NULL
AND Link_Id=p_Link_Id
AND Billing_Indicator = 'L'
GROUP BY Record_Type, Country_Product_Id, Channel_Id
</pre>
I'm having an index on all the columns being searched and all the values being fetched.
Here I want to know if there is some procedure where we can fetch all the data from index itself, & we need not to switch again & again between table & index data.
Thanks
Deepak

Answer 1

That's the kind of thing you want to leave to the optimizer.
Provided you supply it with the information needed, most of the time it will make a better decision than you will on speculation.
You want to avoid "hard coding" execution plans since this is contrary to the principles of the CBO and the "what" vs "where" philosophy underlying declarative programming.
A few thoughts:
1) Possibly the "AND Invoice_Id IS NULL" gets in the way of that of index only lookup
2) To raise an optimizer bug/change request you will need to prove that your suggested plan is (a) possible (b) superior to the optimizer's choice (c) the optimizer choice is based on erroneous logic (possibly via 10053 trace)