{
  "id": "mongodb/mmapv1-lock-acquire-timeout",
  "signature": "MongoServerError: mmapv1 lock acquire timeout",
  "signature_zh": "MongoServerError: mmapv1 锁获取超时",
  "regex": "mmapv1 lock acquire timeout",
  "domain": "mongodb",
  "category": "resource_error",
  "subcategory": null,
  "root_cause": "With the deprecated MMAPv1 storage engine, a write operation waited too long for a database-level lock due to high concurrency.",
  "root_cause_type": "generic",
  "root_cause_zh": "使用已弃用的 MMAPv1 存储引擎时，由于高并发，写入操作等待数据库级锁超时。",
  "versions": [
    {
      "version": "mongodb-3.2",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "mongodb-3.4",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "mongodb-3.6",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "",
      "why_fails": "Increasing lock timeout just delays failure; the underlying contention remains.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    },
    {
      "action": "",
      "why_fails": "Adding more application threads exacerbates lock contention.",
      "fail_rate": 0.95,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Migrate to WiredTiger storage engine which uses document-level concurrency.",
      "success_rate": 0.95,
      "how": "Migrate to WiredTiger storage engine which uses document-level concurrency.",
      "condition": "",
      "sources": []
    },
    {
      "action": "Reduce write concurrency by batching writes or using a queue to serialize operations.",
      "success_rate": 0.7,
      "how": "Reduce write concurrency by batching writes or using a queue to serialize operations.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Migrate to WiredTiger storage engine which uses document-level concurrency.",
    "Reduce write concurrency by batching writes or using a queue to serialize operations."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://www.mongodb.com/docs/v3.6/faq/storage/#does-mmapv1-have-locking-issues",
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.9,
  "resolvable": "true",
  "first_seen": "2023-03-20",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}