parquet-column-chunk · shipping · also column chunk (Parquet)

Parquet column chunk

A Parquet column chunk is a contiguous sequence of encoded pages for one column within one row group.

Related Observatory article: Parquet column chunk on hesela.com

Layout: a chunk belongs to a row group, not to all rows of the file. File metadata locates the chunks a reader needs; a column's chunks across multiple row groups are distinct. [1]

Pages: a chunk may contain multiple data pages and an optional dictionary page. Encoding, compression and optional page checksums operate below the chunk level; a chunk is not necessarily one page or one checksum. [2] [3]

Coverage: reading one column does not establish integrity of an excluded column. Hesela's experiment verifies selected values but does not measure physical reads or prefetch. [4]

Relations

related

parquet, parquet-row-group, parquet-page-checksum

Citations

1. Apache Parquet: file layout and metadata (accessed 2026-10-17)
2. Apache Parquet: column chunks and page organization (accessed 2026-10-17)
3. Apache Parquet: page checksumming (accessed 2026-10-17)
4. Hesela: Parquet checksum and read-coverage experiment (accessed 2026-10-17)

JSON: /data/terms/parquet-column-chunk.json