{
  "id": "redis/stream-consumer-group-pending-entries-overload",
  "signature": "ERR PEL too large for consumer group 'mygroup' on stream 'mystream'",
  "signature_zh": "流 'mystream' 上消费者组 'mygroup' 的待处理条目列表 (PEL) 过大",
  "regex": "ERR PEL too large for consumer group '.*' on stream '.*'",
  "domain": "redis",
  "category": "resource_error",
  "subcategory": null,
  "root_cause": "The Pending Entries List (PEL) for a consumer group has grown excessively large, exceeding Redis internal limits or causing performance degradation.",
  "root_cause_type": "generic",
  "root_cause_zh": "消费者组的待处理条目列表 (PEL) 增长过大，超出了 Redis 内部限制或导致性能下降。",
  "versions": [
    {
      "version": "7.0",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "7.2",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "8.0-m3",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Delete and recreate the consumer group without acknowledging pending messages.",
      "why_fails": "This loses all pending messages and disrupts processing state; messages may be lost permanently.",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    },
    {
      "action": "Increase the stream's max-length to a very high value.",
      "why_fails": "The PEL size is not directly tied to stream length; it depends on unacknowledged messages. Increasing max-length does not help.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    },
    {
      "action": "Restart the Redis server to clear the PEL.",
      "why_fails": "The PEL is persisted and will be restored on restart; this only causes downtime without solving the underlying issue.",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Use XACK to acknowledge processed messages and shrink the PEL. Example: XACK mystream mygroup 1234567890-0 1234567891-0",
      "success_rate": 0.85,
      "how": "Use XACK to acknowledge processed messages and shrink the PEL. Example: XACK mystream mygroup 1234567890-0 1234567891-0",
      "condition": "",
      "sources": []
    },
    {
      "action": "Use XAUTOCLAIM to reclaim idle pending messages and acknowledge them programmatically. Example: XAUTOCLAIM mystream mygroup other-consumer 3600000 0-0 COUNT 100",
      "success_rate": 0.8,
      "how": "Use XAUTOCLAIM to reclaim idle pending messages and acknowledge them programmatically. Example: XAUTOCLAIM mystream mygroup other-consumer 3600000 0-0 COUNT 100",
      "condition": "",
      "sources": []
    },
    {
      "action": "Monitor and limit the number of pending entries per consumer by setting a maximum processing time and acknowledging messages promptly in application code.",
      "success_rate": 0.9,
      "how": "Monitor and limit the number of pending entries per consumer by setting a maximum processing time and acknowledging messages promptly in application code.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "Use XACK to acknowledge processed messages and shrink the PEL. Example: XACK mystream mygroup 1234567890-0 1234567891-0",
    "Use XAUTOCLAIM to reclaim idle pending messages and acknowledge them programmatically. Example: XAUTOCLAIM mystream mygroup other-consumer 3600000 0-0 COUNT 100",
    "Monitor and limit the number of pending entries per consumer by setting a maximum processing time and acknowledging messages promptly in application code."
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://redis.io/docs/latest/commands/xreadgroup/",
  "official_doc_section": null,
  "error_code": "ERR",
  "verification_tier": "ai_generated",
  "confidence": 0.85,
  "fix_success_rate": 0.75,
  "resolvable": "partial",
  "first_seen": "2024-03-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}