{
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-17",
  "slug": "zone-map",
  "term": "Zone map (min-max index)",
  "aliases": [
    "min-max index"
  ],
  "definition": "A zone map is a per-region summary of column-value bounds that lets a reader skip regions that cannot satisfy a query predicate.",
  "note": "A zone map supports exclusion, not membership proof. An overlapping interval remains a candidate even when it contains no matching value. Clustering can make bounds more selective. [columnar-study]\n\nParquet has column-chunk statistics and a separate optional page index; their granularity and reader support must not be conflated. Conservative bounds can include values absent from the data. They must still enclose the relevant values under the specified ordering. [parquet-thrift] [page-index]\n\nCorrectness depends on valid metadata. Hesela's deliberately narrowed footer minimum caused PyArrow 21.0.0 to prune a matching row although all four page-body CRCs remained valid. Wider valid bounds and absent-statistics controls restored it. This is a controlled fixture, not an observed field failure or a cross-reader result. [hesela-statistics]",
  "related": [
    "parquet",
    "parquet-page-checksum",
    "bloom-filter"
  ],
  "advantages": [],
  "limitations": [],
  "citations": [
    {
      "id": "columnar-study",
      "title": "Zeng et al. An Empirical Evaluation of Columnar Storage Formats. PVLDB 17(2), 148-161, 2023. DOI: 10.14778/3626292.3626298",
      "url": "https://www.vldb.org/pvldb/vol17/p148-zeng.pdf",
      "accessed": "2026-10-17"
    },
    {
      "id": "parquet-thrift",
      "title": "Apache Parquet format 2.10.0: Statistics bounds and ColumnOrder",
      "url": "https://github.com/apache/parquet-format/blob/apache-parquet-format-2.10.0/src/main/thrift/parquet.thrift",
      "accessed": "2026-10-17"
    },
    {
      "id": "page-index",
      "title": "Apache Parquet: optional page index",
      "url": "https://parquet.apache.org/docs/file-format/pageindex/",
      "accessed": "2026-10-17"
    },
    {
      "id": "hesela-statistics",
      "title": "Hesela: controlled Parquet footer-statistics observations",
      "url": "https://hesela.dev/research/parquet-statistics.json",
      "accessed": "2026-10-17"
    }
  ]
}