{
  "slug": "sstable",
  "term": "Sorted string table",
  "aliases": [
    "SSTable",
    "SST file"
  ],
  "definition": "An immutable table of sorted key-value entries used as a persistent component in storage engines such as LevelDB and RocksDB.",
  "note": "An SSTable is a file-level component, not an entire LSM-tree. In LevelDB, compaction merges tables and can discard overwritten values or obsolete deletion markers when safe.",
  "related": [
    "lsm-tree",
    "bloom-filter",
    "lsm-tombstone"
  ],
  "citations": [
    {
      "id": "leveldb",
      "title": "LevelDB project. Implementation: log files, sorted tables and compaction. Documentation reviewed 12 October 2026.",
      "url": "https://github.com/google/leveldb/blob/main/doc/impl.md",
      "accessed": "2026-10-12"
    },
    {
      "id": "rocks-levels",
      "title": "RocksDB project. Leveled Compaction: sorted levels, SST files and overlapping L0. Documentation reviewed 12 October 2026.",
      "url": "https://github.com/facebook/rocksdb/wiki/Leveled-Compaction",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela",
      "title": "Hesela: Bloom filters and the cost of an absent LSM lookup",
      "url": "https://hesela.com/analyses/bloom-filters-lsm-read-cost/",
      "accessed": "2026-10-12"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}