When are materialized views NOT recommended?

• A. The view's base table does not change frequently.
• B. Query results require significant processing.
• C. The query is on an external table.
• D. The view's base table changes frequently.

Answer: (D)

Materialized views are precomputed results stored for fast query performance, but they must be refreshed when the underlying data changes. If the base table changes frequently, the system would need to refresh the materialized view very often to stay current. That frequent refresh overhead can consume significant resources and create latency or contention, often erasing the performance benefits of using the materialized view. So, in environments with highly volatile data, materialized views are not recommended. In contrast, when the base data doesn’t change often, the upfront cost of building and refreshing the MV pays off with quicker query responses and minimal maintenance.