Delta Lake Secrets: What Happens After You Run Write, Update or Merge
I wrote a practical deep dive on Delta Lake that explains what actually happens behind the scenes—not just the basic theory.
Most tutorials stop at “Delta supports ACID and Time Travel,” but I wanted to understand how it really works.
In this blog, I covered:
• _delta_log and transaction logs
• Why Delta never deletes old files immediately
• Checkpoints and snapshot mechanism
• Data skipping and how Z-Ordering improves performance
• History, Restore, and Time Travel
• Merge, Update, Delete operations
• Convert Parquet to Delta
• Optimize and the small file problem
• Real PySpark examples for every concept
I tried to explain everything in a simple, practical way with real examples instead of documentation-style theory.
https://medium.com/@wnccpdfvz/why-delta-lake-is-faster-than-traditional-data-lakes-5c865f67b66b