Delta Lake is an open-source storage framework that brings ACID transactions, scalable metadata handling, and time travel to cloud data lakes. Built on top of Parquet, it provides a transactional layer through an append-only commit log (_delta_log) that records every change, enabling reliable concurrent writes and schema evolution without sacrificing performance. Originally developed by Databricks and now a Linux Foundation project, Delta Lake bridges the reliability gap between data warehouses and data lakes, making it the foundation for modern lakehouse architectures on AWS S3, Azure ADLS, and Google Cloud Storage.

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