Low cardinality,high concurrent in OLTP, how to improve query performance?

In our racle DB 10g application we have a table that is INSERTED highly concurrently in OLTP application (but are NEVER UPDATED, Insert Only).
There is a column : IS_PROCESSED VARCHAR2(1) , values is : 'Y' or
'N' .

The rows will grows by a mill rows in a month. The default value is
'N' then on nightly basis a JOB will run to do some process and update
to 'Y'.

So, only the daily data will have 'N' value, one day later it will become 'Y'.

The requirement in the OLTP is there will be many concurrent access that wil query :

SELECT X, Y, Z , SUM(A), SUM (B) from the_table WHERE IS_PROCESSED =
'N' GROUP BY (X,Y,Z)
The docs says that B-Tree index wont help and Bitmap Index is not for OLTP, what how can I avoid Full table Scan in this query ?

Thank you for your help,
xtanto Received on Sat Jan 31 2009 - 16:54:15 CST