{
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-13",
  "slug": "monotonic-writes",
  "term": "Monotonic writes",
  "aliases": [
    "Monotonic-write consistency",
    "MW session guarantee"
  ],
  "definition": "Monotonic writes requires every replica incorporating a later session write to incorporate the session's earlier writes and order them before it.",
  "note": "This is write ordering, not increasing numeric values. MongoDB's causal-session documentation allows unrelated writes to interleave; one thread must use the session at a time. Its documented majority read and write concerns provide all four causal guarantees with durability; weaker configurations require separate analysis.",
  "related": [
    "session-guarantees",
    "writes-follow-reads"
  ],
  "citations": [
    {
      "id": "session-guarantees",
      "title": "Douglas B. Terry et al. Session Guarantees for Weakly Consistent Replicated Data. PDIS 1994, sections 3.1-3.4, pp. 142-144.",
      "url": "https://classes.cs.uchicago.edu/archive/2026/spring/23380-1/papers/terry_sessionguarantees.pdf",
      "accessed": "2026-10-13"
    },
    {
      "id": "mongodb-sessions",
      "title": "MongoDB Manual: Read Isolation, Consistency, and Recency; client sessions, causal guarantees and isolation.",
      "url": "https://www.mongodb.com/docs/manual/core/read-isolation-consistency-recency/",
      "accessed": "2026-10-13"
    },
    {
      "id": "hesela-consistency",
      "title": "Storage consistency: ordering is not a transaction or a durability promise",
      "url": "https://hesela.com/analyses/storage-consistency-ordering/",
      "accessed": "2026-10-13"
    },
    {
      "id": "mongodb-concerns",
      "title": "MongoDB Manual: Causal Consistency and Read and Write Concerns; durability and rollback distinctions.",
      "url": "https://www.mongodb.com/docs/manual/core/causal-consistency-read-write-concerns/",
      "accessed": "2026-10-13"
    }
  ]
}