{
  "slug": "kreon",
  "term": "Kreon",
  "aliases": [
    "Kreon key-value store"
  ],
  "definition": "Kreon is a research key-value store that combines a separate value log with a multilevel index containing a B-tree at each level.",
  "note": "Spills update affected parts of the next level instead of rewriting its entire contents. Log cleaning still moves live records and updates their index references. [kreon-thesis]\n\nThe research design uses a custom kmmap kernel path with page priorities, not only standard mmap. L0 can be reconstructed from the persisted log suffix; its checkpoint reduces replay work. That does not establish durability of every acknowledged insert. [kreon-thesis]",
  "citations": [
    {
      "id": "kreon-thesis",
      "title": "Papagiannis. Memory-Mapped I/O for Fast Storage. PhD dissertation, December 2020, chapter 3, sections 3.2.1-3.2.3.",
      "url": "https://tpapagian.github.io/files/apapag_phd_thesis.pdf",
      "accessed": "2026-11-10"
    },
    {
      "id": "kreon-project",
      "title": "Kreon author repository, pinned README: multilevel B+-tree indexing and benchmark build configurations.",
      "url": "https://github.com/CARV-ICS-FORTH/kreon/blob/20d81746783dc1155e69e7f4f40af483059f3ec2/README.md",
      "accessed": "2026-11-10"
    },
    {
      "id": "hesela-kv",
      "title": "Hesela: Tucana, Kreon and the cost of mapped writes",
      "url": "https://hesela.com/analyses/key-value-separation-cleaning-cost/#mapped-write-cost",
      "accessed": "2026-11-10"
    }
  ],
  "related": [
    "key-value-separation",
    "value-log",
    "tucana"
  ],
  "status": "research",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-10",
  "provenance": [
    "The pinned repository describes a multilevel B+-tree index. The dissertation supplies the custom-kernel and recovery discussion; the repository was not executed. [kreon-project] [kreon-thesis]"
  ]
}