The optimizer uses a cost-based approach and optimizes with a goal of best response time to return the first
n rows (where
n = 1, 10, 100, 1000).
The optimizer uses a mix of costs and heuristics to find a best plan for fast delivery of the first few rows.
The optimizer uses a cost-based approach for all SQL statements in the session and optimizes with a goal of best throughput (minimum resource use to complete the entire statement).