{
  "slug": "lsm-tombstone",
  "term": "LSM tombstone",
  "aliases": [
    "deletion marker",
    "point tombstone"
  ],
  "definition": "An LSM tombstone is a versioned deletion marker that suppresses older values for a key without immediately erasing their stored bytes.",
  "note": "A marker can remain necessary while an older table still contains a value it hides; removing the marker alone can expose obsolete data. Snapshot visibility can also require retaining old versions.",
  "related": [
    "lsm-tree",
    "sstable",
    "range-tombstone",
    "delete-persistence-latency"
  ],
  "citations": [
    {
      "id": "leveldb",
      "title": "LevelDB project. Implementation: sorted tables and compaction.",
      "url": "https://github.com/google/leveldb/blob/main/doc/impl.md",
      "accessed": "2026-10-12"
    },
    {
      "id": "snapshots",
      "title": "RocksDB project. Snapshot: sequence numbers, point-in-time reads and lifetime.",
      "url": "https://github.com/facebook/rocksdb/wiki/Snapshot",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela",
      "title": "LSM tombstones: deleted is not yet reclaimed",
      "url": "https://hesela.com/analyses/lsm-tombstones-delete-persistence/",
      "accessed": "2026-10-12"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}