How does the cost-based optimizer (CBO) in Presto improve query performance in watsonx.data?

The CBO uses statistics (row counts; column cardinality; data distribution) to evaluate multiple execution plans and choose the one with the lowest estimated cost; particularly effective for multi-table join order optimization. The incorrect options ("It dynamically adds more worker nodes to the engine during query execution", "It rewrites all SQL queries to use GROUP BY before executing them", "It caches query results in object storage for faster repeated access") are distractors that don't fully capture the concept described.