Question 30

A compliance team requires that deleted customer records be physically removed from object storage within 30 days, but data engineers also rely on Delta Lake time travel to recover from accidental writes during long-running multi-day ingestion jobs. An engineer proposes running the following on the managed Delta table `crm.gold.customers` every night to aggressively reclaim storage: ```sql VACUUM crm.gold.customers RETAIN 1 HOURS; ``` Which statement correctly describes the behavior and risk of this command?

• AThe command runs as written; `VACUUM` removes files older than 1 hour, which safely reclaims storage with no impact on running jobs or time travel.
• BBy default Delta Lake's safety check blocks a retention interval below 7 days; the command raises an error unless `spark.databricks.delta.retentionDurationCheck.enabled` is set to `false`, and even then a 1-hour threshold risks deleting files written by uncommitted long-running jobs and destroys time travel beyond 1 hour.
• C`VACUUM` only deletes Delta transaction log (`_delta_log`) files, so the `RETAIN` value affects log retention but never the data files, making the command harmless.
• D`RETAIN 1 HOURS` is ignored on Unity Catalog managed tables; managed tables always enforce a fixed 30-day retention that cannot be changed.