In fact, footer metadata and offset-based addressing already provide everything needed to embed user-defined index structures within Parquet files without breaking compatibility with other Parquet readers. However, Parquet is extensible with user-defined indexes: Parquet tolerates unknown bytes within the file body and permits arbitrary key/value pairs in its footer metadata. Parquet File Anatomy & Standard Index StructuresLogically, Parquet files contain row groups, each with column chunks, which in turn contain data pages. Example: Embedding a User Defined Distinct Value Index in Parquet FilesThis section demonstrates how to embed a simple distinct value index in Parquet files and use it for file-level pruning (skipping) in DataFusion. Introduction to Distinct Value IndexesA distinct value index stores the unique values of a specific column.