Metadata in Parquet files plays a crucial role in improving data efficiency, enabling faster queries and optimized storage. This feature allows query engines to make decisions about which data to read, skip rows, and optimize query execution without scanning the entire dataset. Parquet files store metadata at three levels: file-level, row group-level, and column-level. By leveraging this rich metadata, users can enjoy improved query performance through predicate pushdown, column pruning, and row group skipping.

Source: https://dev.to/alexmercedcoder/all-about-parquet-part-07-metadata-in-parquet-improving-data-efficiency-46h3