{
  "schema": "pg36-ch34-classification-contract-v1",
  "common_alert": "postgresql-resource-headroom-at-risk",
  "required_packet_fields": [
    "case_id",
    "observed_at",
    "connection",
    "retention",
    "engine",
    "filesystem"
  ],
  "routes": [
    {
      "route": "RELIEVE_FLOW_PRESSURE",
      "requires": [
        "connection.observed_sessions >= 18",
        "connection.connection_rejections >= 1",
        "connection.lock_waiters >= 1",
        "retention.inactive_physical_slots = 0"
      ],
      "safe_action": "cancel exact fixture sessions, then reduce admission/retry pressure",
      "forbidden_shortcut": "increase max_connections during the incident"
    },
    {
      "route": "PRESERVE_RETENTION_EVIDENCE",
      "requires": [
        "retention.inactive_physical_slots = 1",
        "retention.retained_wal_bytes >= 33554432",
        "connection.connection_rejections = 0"
      ],
      "safe_action": "identify the retention owner and protect evidence; only an exact disposable owned slot may be dropped in this lab",
      "forbidden_shortcut": "delete files from pg_wal"
    }
  ],
  "unknown_route": {
    "route": "STOP_AND_INVESTIGATE",
    "when": "neither or both route predicates match",
    "actions": [
      "stop destructive cleanup",
      "preserve SQL and host evidence",
      "name unresolved facts",
      "escalate to the incident commander"
    ]
  },
  "wrong_route_cost": {
    "flow_as_retention": "no admission relief; connection failures and queueing continue",
    "retention_as_flow": "canceling sessions does not release restart_lsn; WAL continues to be retained",
    "delete_pg_wal": "can make crash recovery or replication impossible and destroys evidence"
  },
  "production_ch34_gate": "pending"
}