Clustering information maintained for micro-partitions includes which of the following?

• A. The total number of micro-partitions.
• B. The number of overlapping micro-partitions only.
• C. The depth of overlapping micro-partitions only.
• D. All of the above.

Answer: (D)

Clustering information for micro-partitions captures how data is distributed with respect to the clustering keys and how much data would be touched by a clustering-based prune. It includes the total number of micro-partitions, which shows the scale of the partitioning. It also records how many micro-partitions overlap with the clustering key ranges, indicating how many partitions could be affected by a query predicate on the clustering key. In addition, it stores the depth of overlapping micro-partitions, which reveals how many layers of overlap exist across partitions for the clustering keys. Together, these metrics describe the clustering structure and the potential maintenance cost of keeping data well-clustered. Since all three aspects are tracked, the correct answer is that all of the above.