Exam DP-750 Topic 1 Question 46 Discussion

To diminish storage costs while preserving 60 days of time travel history, you must perform the following two actions: Set the delta.deletedFileRetentionDuration table property to 60 days and Run the vacuum command on the table.
Set the delta.deletedFileRetentionDuration table property to 30 days
This property controls how long data files must be deleted before they become eligible for removal by a cleanup process. By default, it is set to 7 days. Increasing it to 60 days ensures that Delta Lake preserves the underlying parquet files required to query any historical snapshot within your 30-day time travel window.
Run the vacuum command on the tableChanging the retention property alone does not delete files or reduce costs. You must explicitly execute the VACUUM command. The command scans the table and permanently deletes uncommitted or deleted data files that are older than the 60- day threshold defined by your retention duration, thereby freeing up storage space.
Incorrect:
[Not C]
Set the delta.logRetentionDuration table property to 30 days
This property controls how long the transaction log (_delta_log) history is kept, which defaults to
30 days. While the transaction log is required for time travel, modifying this property alone does not delete the heavy data files causing high storage costs. Furthermore, it governs the logs rather than the actual deleted data files.
Reference:
https://www.cloudmatter.io/post/data-audit-with-databricks-delta-time-travel