All, I read the below content in Oracle help. I am trying to understand some thing here. Does ALL_ROWS/FIRST_ROWS work regardless of statistics????
The optimizer uses a cost-based approach for all SQL statements in the session regardless of the presence of statistics and optimizes with a goal of best throughput (minimum resource use to complete the entire statement).
The optimizer uses a cost-based approach, regardless of the presence of statistics, and optimizes with a goal of best response time to return the first n number of rows; n can equal 1, 10, 100, or 1000.
The optimizer uses a mix of cost and heuristics to find a best plan for fast delivery of the first few rows.