Hi Tanmoy, my two cents. Why don't you try to create a test environment and move to CBO, recalculate full statistics and see. Maybe this could be your real solution. This is risky, but this could solve several present and future problems at once. Anyway rule mode had been deprecated, there is no reason to continue using it. Soon or later your system will have to move to cbo, and I think is better soon. -- //www.freelists.org/webpage/oracle-l