{
  "description": "答え合わせページ②「締切後記録26件の内訳と原因」の裏付けデータ。2026-09-11に本番VPS(PostgreSQL・SELECT専用)へ直接クエリして取得した、late_snapshot=trueの全26件の締切時刻・記録時刻・遅延秒数・同時間帯の混雑度(締切前後3分以内に締切を迎えた他会場のレース数、自分自身を含む)。DBの更新・削除は一切行っていない。",
  "queried_at_jst": "2026-09-11T14:05:00+09:00",
  "population": "prediction_reconciliation.late_snapshot=true (07-12〜09-10累計)",
  "row_count": 26,
  "rows": [
    {
      "race_date": "2026-08-17",
      "stadium_id": 2,
      "race_number": 11,
      "race_closed_at": "2026-08-17 15:55:00+09",
      "snapshot_at": "2026-08-17 15:55:08.484819+09",
      "late_seconds": 8.5,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-08-17",
      "stadium_id": 22,
      "race_number": 9,
      "race_closed_at": "2026-08-17 16:28:00+09",
      "snapshot_at": "2026-08-17 16:28:22.358966+09",
      "late_seconds": 22.4,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 8,
      "race_number": 5,
      "race_closed_at": "2026-08-26 12:31:00+09",
      "snapshot_at": "2026-08-26 12:31:25.557462+09",
      "late_seconds": 25.6,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 18,
      "race_number": 9,
      "race_closed_at": "2026-08-26 12:33:00+09",
      "snapshot_at": "2026-08-26 12:33:25.473142+09",
      "late_seconds": 25.5,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 3,
      "race_number": 4,
      "race_closed_at": "2026-08-26 12:35:00+09",
      "snapshot_at": "2026-08-26 12:35:22.023587+09",
      "late_seconds": 22.0,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 10,
      "race_number": 9,
      "race_closed_at": "2026-08-26 12:40:00+09",
      "snapshot_at": "2026-08-26 12:40:17.694759+09",
      "late_seconds": 17.7,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 18,
      "race_number": 11,
      "race_closed_at": "2026-08-26 13:41:00+09",
      "snapshot_at": "2026-08-26 13:41:05.454213+09",
      "late_seconds": 5.5,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 6,
      "race_number": 10,
      "race_closed_at": "2026-08-26 15:58:00+09",
      "snapshot_at": "2026-08-26 15:58:25.006914+09",
      "late_seconds": 25.0,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 11,
      "race_number": 12,
      "race_closed_at": "2026-08-26 16:06:00+09",
      "snapshot_at": "2026-08-26 16:06:01.973139+09",
      "late_seconds": 2.0,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-08-26",
      "stadium_id": 1,
      "race_number": 4,
      "race_closed_at": "2026-08-26 16:23:00+09",
      "snapshot_at": "2026-08-26 16:23:13.014565+09",
      "late_seconds": 13.0,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-08-30",
      "stadium_id": 11,
      "race_number": 5,
      "race_closed_at": "2026-08-30 12:37:00+09",
      "snapshot_at": "2026-08-30 12:37:01.079944+09",
      "late_seconds": 1.1,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-08-30",
      "stadium_id": 11,
      "race_number": 6,
      "race_closed_at": "2026-08-30 13:08:00+09",
      "snapshot_at": "2026-08-30 13:08:09.806074+09",
      "late_seconds": 9.8,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-08-30",
      "stadium_id": 8,
      "race_number": 12,
      "race_closed_at": "2026-08-30 16:19:00+09",
      "snapshot_at": "2026-08-30 16:19:22.630543+09",
      "late_seconds": 22.6,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-08-30",
      "stadium_id": 1,
      "race_number": 4,
      "race_closed_at": "2026-08-30 16:23:00+09",
      "snapshot_at": "2026-08-30 16:23:16.802862+09",
      "late_seconds": 16.8,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-09-03",
      "stadium_id": 20,
      "race_number": 3,
      "race_closed_at": "2026-09-03 16:12:00+09",
      "snapshot_at": "2026-09-03 16:12:02.666073+09",
      "late_seconds": 2.7,
      "races_closing_within_3min_incl_self": 4
    },
    {
      "race_date": "2026-09-03",
      "stadium_id": 8,
      "race_number": 12,
      "race_closed_at": "2026-09-03 16:15:00+09",
      "snapshot_at": "2026-09-03 16:15:06.149463+09",
      "late_seconds": 6.1,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-03",
      "stadium_id": 19,
      "race_number": 3,
      "race_closed_at": "2026-09-03 16:19:00+09",
      "snapshot_at": "2026-09-03 16:19:01.455835+09",
      "late_seconds": 1.5,
      "races_closing_within_3min_incl_self": 1
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 4,
      "race_number": 10,
      "race_closed_at": "2026-09-05 15:29:00+09",
      "snapshot_at": "2026-09-05 15:29:11.810849+09",
      "late_seconds": 11.8,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 22,
      "race_number": 8,
      "race_closed_at": "2026-09-05 15:31:00+09",
      "snapshot_at": "2026-09-05 15:31:11.88081+09",
      "late_seconds": 11.9,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 13,
      "race_number": 11,
      "race_closed_at": "2026-09-05 15:36:00+09",
      "snapshot_at": "2026-09-05 15:36:07.792336+09",
      "late_seconds": 7.8,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 11,
      "race_number": 11,
      "race_closed_at": "2026-09-05 15:38:00+09",
      "snapshot_at": "2026-09-05 15:38:06.065076+09",
      "late_seconds": 6.1,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 20,
      "race_number": 2,
      "race_closed_at": "2026-09-05 16:01:00+09",
      "snapshot_at": "2026-09-05 16:01:13.445132+09",
      "late_seconds": 13.4,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 1,
      "race_number": 3,
      "race_closed_at": "2026-09-05 16:07:00+09",
      "snapshot_at": "2026-09-05 16:07:12.563163+09",
      "late_seconds": 12.6,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 11,
      "race_number": 12,
      "race_closed_at": "2026-09-05 16:14:00+09",
      "snapshot_at": "2026-09-05 16:14:08.011841+09",
      "late_seconds": 8.0,
      "races_closing_within_3min_incl_self": 3
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 22,
      "race_number": 10,
      "race_closed_at": "2026-09-05 16:23:00+09",
      "snapshot_at": "2026-09-05 16:23:25.617112+09",
      "late_seconds": 25.6,
      "races_closing_within_3min_incl_self": 2
    },
    {
      "race_date": "2026-09-05",
      "stadium_id": 2,
      "race_number": 12,
      "race_closed_at": "2026-09-05 16:30:00+09",
      "snapshot_at": "2026-09-05 16:30:18.409569+09",
      "late_seconds": 18.4,
      "races_closing_within_3min_incl_self": 3
    }
  ],
  "timing_summary": {
    "min_late_seconds": 1.1,
    "max_late_seconds": 25.6,
    "mean_late_seconds": 13.2,
    "note": "全26件が26秒以内(分単位ではなく秒単位)の遅延。全体(late_snapshotを含む累計9,194件)の記録タイミング中央値は締切の242秒前(約4分前)、締切60秒前以内に滑り込んだ行が108件。"
  },
  "root_cause": {
    "mechanism": "予想の自動記録(prediction_snapshot)は smart_scheduler.py が締切(race_closed_at)の5分前(SNAPSHOT_MINUTES=5)にサブプロセスとして起動するようスケジュールしている。この単一のイベントキューは24会場ぶんのオッズ取得・結果取得・予想記録イベントを時刻順に1つずつ逐次実行する設計であり、複数レースの処理が近い時刻に集中すると実行そのものが後ろへずれることがある。",
    "safety_valve_added": "2026-07-15",
    "safety_valve_reason": "遅延を理由にイベントをスキップする実装だった際、2026-07-15に78レース分の予想スナップショットが丸ごと欠測する事故が発生した。再発防止のため、prediction_snapshotイベントに限り『15分以内の遅延なら省略せず遅延実行する』フォールバックを追加した(smart_scheduler.py内のコメントに経緯を明記)。",
    "conclusion": "検出された26件は、いずれも遅延が最大25.6秒(=スケジュール上の余裕5分を使い切った直後)で発生しており、上記フォールバックの許容範囲(15分以内)に対して極めて小さい。したがって今回の26件は新規に発生した不具合ではなく、2026-07-15から存在する既知の安全弁設計が、締切直前の混雑によって締切をわずかに超えて発動した結果であると判定した。congestion(races_closing_within_3min_incl_self)は1〜4件と、全国24会場体制の中では低い部類に入るが、この程度の重なりでも同一プロセスの逐次実行により秒単位の遅延が積み重なり得ることを示している。",
    "judgement": "想定内の境界事象(仕組みの不具合ではない)。ただし発生数はゼロにはならない見込みであり、記録タイミングの安全マージン(現在5分)や逐次実行方式の見直しは今後の改善余地として申し送る。",
    "action_taken_this_session": "本番のスケジューラー(smart_scheduler.py)・予想モデル・DBの記録は一切変更していない。過去のlate_snapshot行(UPDATE/DELETE)も一切変更していない。"
  }
}