Data engineering·Files, formats and table layers
there is a _delta_log folder of JSON commits next to the Parquet, and reading the table means replaying that log.
Delta Lake
Also calledDelta, delta table
An open table format whose metadata is an ordered transaction log of commits alongside the data files. It came out of the Spark ecosystem and is deeply integrated with it, and its log-based design makes change data feeds and time travel natural. The practical difference from other formats is mostly ecosystem and maintenance vocabulary rather than capability.