Table Formats Iceberg and Delta Lake

A few metadata files kept next to a folder of Parquet files can list exactly which data files make up a table at each moment (a table format). Without them, the folder is not yet a table. A reader that lists it during a write can see half of the new files, two jobs can write at once without knowing about each other, and nothing records which files belonged to yesterday's version.

**A table format is a specification for metadata files that turn a set of data files into one table, with a schema, partition rules, and a recorded history of versions