In Delta Lake, what is the purpose of the VACUUM command?

• A. Remove files no longer used by the table beyond a retention threshold
• B. Compress data files
• C. Change the table schema
• D. Remove rows from the table

Answer: (A)

VACUUM cleans up storage by permanently removing data files that are no longer used by the table after a retention period. When you update or delete data, Delta Lake may leave older data files on storage; the transaction log tracks which files are still referenced by the table's versions. VACUUM scans this log and deletes only those unreferenced files that are older than the specified retention window, reclaiming space without touching active data. It doesn’t compress data, change the schema, or remove individual rows directly; those actions are handled by other commands or DML. The retention setting protects against accidental data loss by ensuring some period of time before files are removed.