Answer: Bytes scanned, Number of partitions scanned

The correct answers are A (Bytes scanned) and C (Number of partitions scanned). Bytes scanned directly impacts query performance and cost, as reducing the volume of data processed through efficient filtering or clustering improves speed. Number of partitions scanned reflects partition pruning efficiency, where scanning fewer partitions minimizes unnecessary data access. These metrics are critical for identifying bottlenecks in data retrieval. While D (Percentage scanned from cache) can indicate performance benefits from caching, it's not a primary optimization target since cache usage depends on query patterns and is not directly controllable. B (Bytes sent over the network) and E (External bytes scanned) are less directly tied to core query optimization strategies. The community consensus strongly supports AC, with the highest upvoted comments providing detailed reasoning about data volume and partition pruning as key optimization areas.

Author: LeetQuiz Editorial Team