{
  "captured_at": "2026-07-30T00:11:56.861516Z",
  "decision": {
    "candidate_p95_ratio_max": 1.05,
    "minimum_material_gain_percent": 2,
    "persistent_change_applied": false,
    "production_ch27_gate": "pending",
    "result": "reject-persistent-change",
    "rules": {
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      "candidate_p95_ratio_at_most_1_05": true,
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      "paired_tps_ratio_bootstrap_lower_at_least_1_02": false,
      "plan_shapes_equal_for_probes": true
    }
  },
  "environment": {
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      "host": "pg-meta-1"
    },
    "configuration_facts": {
      "effective_cache_size": {
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        "pending_restart": false,
        "setting": "187520",
        "source": "configuration file",
        "unit": "8kB"
      },
      "fsync": {
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        "setting": "on",
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      },
      "full_page_writes": {
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        "setting": "on",
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      },
      "max_connections": {
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        "setting": "500",
        "source": "command line",
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      },
      "plan_cache_mode": {
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        "setting": "auto",
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      },
      "shared_buffers": {
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        "setting": "62592",
        "source": "configuration file",
        "unit": "8kB"
      },
      "synchronous_commit": {
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        "pending_restart": false,
        "setting": "on",
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        "unit": null
      },
      "wal_compression": {
        "context": "superuser",
        "pending_restart": false,
        "setting": "lz4",
        "source": "configuration file",
        "unit": null
      },
      "work_mem": {
        "context": "user",
        "pending_restart": false,
        "setting": "65536",
        "source": "configuration file",
        "unit": "kB"
      }
    },
    "server": {
      "cpu_count": 1,
      "host": "pg-test-1",
      "memory_bytes": 2048679936,
      "postgresql": "18.4 (Ubuntu 18.4-1.pgdg24.04+1)"
    }
  },
  "experiment": {
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        "failures": 0,
        "late_transactions": 0,
        "latency_ms": {
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          "p50": 1.279,
          "p95": 9.217,
          "p99": 13.126779999999998
        },
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        "skipped_transactions": 0,
        "temp_bytes": 0,
        "tps_median": 2981.721967,
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      },
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        "failures": 0,
        "late_transactions": 0,
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          "p99": 12.933389999999985
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    "clients": 8,
    "counterbalanced": true,
    "dataset_scale": "M",
    "measured_runs": 10,
    "measured_seconds_per_run": 12,
    "paired_repetitions": 5,
    "paired_seeds": true,
    "paired_tps_ratio_bootstrap_95": [
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    "plan_shapes_equal_for_probes": true,
    "prepared_plan_counts": {
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          "custom_plans": 5,
          "generic_plans": 5,
          "name": "ch27_order",
          "parameter_types": [
            "bigint"
          ]
        },
        {
          "custom_plans": 5,
          "generic_plans": 5,
          "name": "ch27_product",
          "parameter_types": [
            "bigint"
          ]
        }
      ],
      "force_generic_plan": [
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          "generic_plans": 10,
          "name": "ch27_order",
          "parameter_types": [
            "bigint"
          ]
        },
        {
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          "generic_plans": 10,
          "name": "ch27_product",
          "parameter_types": [
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          ]
        }
      ]
    },
    "transactions": 357685
  },
  "hypothesis": {
    "baseline": "auto",
    "candidate": "force_generic_plan",
    "parameter": "plan_cache_mode",
    "persistent_configuration_change": false,
    "rollback": "session-end",
    "scope": "benchmark-session-only"
  },
  "preflight_run_id": "d06c94b2-efb0-4688-86bf-b4e6ca92b90f",
  "rejected_untested_changes": [
    {
      "parameter": "work_mem",
      "reason": "no spill mechanism was observed"
    },
    {
      "parameter": "shared_buffers",
      "reason": "I/O was not established as the limiting service center; restart and memory-budget effects are material"
    },
    {
      "parameter": "max_connections",
      "reason": "connection slots are not throughput and can amplify memory and queueing"
    },
    {
      "parameter": "synchronous_commit",
      "reason": "changes the durability contract"
    },
    {
      "parameter": "wal_compression",
      "reason": "mechanism and tradeoff do not match the observed constraint"
    }
  ],
  "release": "1.0-sandbox",
  "risk": "L2-bounded-session-local-parameter-experiment",
  "run_id": "efb7efec-beb2-4237-8535-6864de2a2e4e",
  "schema": "pg36-ch27-reference-run-v1",
  "target": "pg36-l2-vagrant/pg-test",
  "upstream": {
    "chapter26_all_temp_bytes_zero": true,
    "chapter26_exact_knee_known": false,
    "chapter26_production_tps": null,
    "chapter26_run_id": "6c44ebdb-2206-48c3-8089-d90fdff45204"
  },
  "validation": {
    "counterexamples_rejected": 28,
    "database_cleanup_verified": true,
    "global_settings_unchanged": true,
    "positive_validation_passed": true,
    "raw_files_verified": 60,
    "raw_query_text_public": false,
    "raw_settings_paths_public": false,
    "raw_transaction_logs_public": false,
    "remote_temp_cleanup_verified": true,
    "role_cleanup_verified": true,
    "secret_material_public": false
  }
}