Mastering Delta Table Vacuum Strategy: A Hidden Gem for Cost Optimization in Databricks

Photo by Michael Dziedzic on Unsplash

One of the easiest (yet often overlooked) cost-saving strategies for Databricks workloads is mastering your Delta Table vacuum strategy. 💡

Why It Matters:

Delta tables are versioned and append-only, which means each update or overwrite creates new data files, leading to storage bloat over time. If your ETL jobs perform full Delta table overwrites, the old versions persist, driving up cloud storage costs.

The Solution: A Solid Vacuum Strategy

The VACUUM command helps manage storage by removing unneeded files. But the trick lies in optimizing its usage:

• When to Vacuum: Should you run the vacuum command at the job level or across the entire platform?
• Retention Period: By default, Delta tables retain files for 7 days to ensure data consistency and support time travel. But you can adjust this with:

ALTER TABLE table_name SET TBLPROPERTIES ('delta.deletedFileRetentionDuration' = '30 days');

This is particularly useful for tables with frequent updates.

Managed vs. Unmanaged Tables: