What Delta Lake command removes files that are no longer referenced and older than the retention threshold?

• A. VACUUM
• B. DROP FILES
• C. TRUNCATE
• D. CLEANUP

Answer: (A)

Delta Lake cleans up old, unreferenced data files with the VACUUM command. It looks at the table’s current state via the transaction log and deletes files that are no longer referenced by any active snapshot and that have aged beyond the retention window. You can specify the retention period, for example VACUUM table RETAIN 7 DAYS (or RETAIN 168 HOURS). This preserves data for time travel within the retention window while removing obsolete files to reclaim storage.

Other options don’t perform this cleanup. They don’t physically remove unreferenced files based on a retention threshold, so they aren’t appropriate for this task.