{
  "aliases": [],
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "The default evaluation disabled crash consistency, hotness awareness and selective separation. Its vLog baseline was the authors' own implementation, not a direct execution of the WiscKey artifact.",
      "citationIds": [
        "hashkv-paper"
      ]
    }
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-14",
  "slug": "hashkv",
  "term": "HashKV",
  "definition": "HashKV is a research key-value store that hashes keys into value-storage groups to localize update processing and garbage collection.",
  "note": "A segment group includes a main segment and overflow log segments. Cleaning reconstructs the latest versions from that group and the write cache, then updates relocated addresses in the LSM-tree. [hashkv-paper]\n\nIts hot/cold extension retains tags in the group and puts cold values in a separate log with vLog-style cleaning. Thus, avoiding group-validity lookups does not eliminate every index lookup or update. [hashkv-paper]",
  "related": [
    "key-value-separation",
    "value-log",
    "wisckey"
  ],
  "citations": [
    {
      "id": "hashkv-paper",
      "title": "Chan, Li, Lee and Xu. HashKV: Enabling Efficient Updates in KV Storage via Hashing. USENIX ATC 2018, pp. 1007-1019, sections 3.2-3.4 and 4.1.",
      "url": "https://files.usenix.org/s3fs-public/cdn/atc18-chan.pdf",
      "accessed": "2026-11-14"
    },
    {
      "id": "hesela-kv",
      "title": "Hesela: key-value separation and cleaning authority.",
      "url": "https://hesela.com/analyses/key-value-separation-cleaning-cost/#cleaning-authority",
      "accessed": "2026-11-14"
    }
  ],
  "provenance": [
    "Historical source review; no independent throughput, durability or crash-recovery reproduction."
  ]
}