Delta Lake

ELI5 - The Vibe Check

Delta Lake is Iceberg's cousin from the Databricks side of the family, same basic idea: bolt ACID transactions and version history onto a pile of Parquet files sitting in cloud storage. The trick is a transaction log next to your data that records every single change, so readers always see a consistent table even while writers are mid-write.

Real Talk

Delta Lake is an open-source storage layer that brings ACID transactions, scalable metadata handling, and unified batch and streaming processing to data lakes built on Parquet files. It uses a write-ahead transaction log (the _delta_log) to track every commit, enabling time travel, schema enforcement, and safe concurrent writes.

Show Me The Code

SELECT * FROM orders VERSION AS OF 12;
-- or by timestamp:
SELECT * FROM orders TIMESTAMP AS OF '2026-08-01';

When You'll Hear This

"Our Spark pipeline writes to Delta Lake so late-arriving records don't corrupt the table." / "Roll back to yesterday's Delta version, the ETL job wrote garbage."