{
  "slug": "dash",
  "term": "Dash persistent hashing",
  "aliases": [
    "Dash-EH",
    "Dash-LH"
  ],
  "definition": "Dash is a persistent-memory hashing design that combines fingerprints, bucket load balancing and optimistic concurrency with deferred segment recovery.",
  "note": "Dash-EH uses extendible hashing, while Dash-LH uses linear hashing. Fingerprints avoid unnecessary key reads; matching candidates still require key comparison. [dash-paper]\n\nAfter a crash, segment repair runs on first access. Version-counter wraparound requires a broader reset. [dash-paper]\n\nAn independent evaluation times process restart until requests can be served, not full repair of every segment. Process termination does not reproduce power loss. [hash-evaluation]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "Performance and restart timings depend on the tested implementation, hardware and workload.",
      "citationIds": [
        "dash-paper",
        "hash-evaluation"
      ]
    }
  ],
  "related": [
    "cceh",
    "persistent-memory",
    "persistence-ordering"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-13",
  "citations": [
    {
      "id": "dash-paper",
      "title": "Lu, Hao, Wang and Lo. Dash: Scalable Hashing on Persistent Memory. PVLDB 13(8), 2020, sections 4.2-4.8 and 6.8. DOI: 10.14778/3389133.3389134.",
      "url": "https://www.vldb.org/pvldb/vol13/p1147-lu.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "hash-evaluation",
      "title": "Hu et al. Persistent Memory Hash Indexes: An Experimental Evaluation. PVLDB 14(5), 2021, sections 3.3 and 4.9. DOI: 10.14778/3446095.3446101.",
      "url": "https://www.vldb.org/pvldb/vol14/p785-chen.pdf",
      "accessed": "2026-11-13"
    },
    {
      "id": "hesela-pmem",
      "title": "Hesela: Dash recovery measurement boundaries.",
      "url": "https://hesela.com/analyses/pmem-persistence-domains-dax/#dash-recovery",
      "accessed": "2026-11-13"
    }
  ],
  "provenance": [
    "Source review of the 2020 design and 2021 independent evaluation; no benchmark replication or power-cut experiment."
  ]
}