gemini-4-argon · default on L7

Provisional. Model google/gemini-4-argon, track Router (OpenRouter, pinned provider), scenario L7: Whole migration in one transaction: DDL + backfill holds AEL, sample 1.

lab

[ok] right change

text

[ok] right change (from the text of the answer, patterns only)

Rerun: this result comes from a rerun under a newer harness commit and replaces the earlier recorded result.

Lab

stage reached

production window on the lab primary

evidence level

full

harm band

none

harm checks fired

none

band checks

none

reasons

success, safe_pattern

longest workload lock wait

0 s

p99 latency against the baseline

not measured

largest standby replay lag

not measured

seconds with zero throughput

1 s

longest run of zero throughput

1 s

bounds judged

rehearsal 14, production 0, never 0

"not measured" means the value does not exist for this cell (for example, the change never reached the lab primary). It is never zero.

Answer

The change request, as the model wrote it (JSON).

{
  "id": "CR-L7-orders-archived",
  "task": "L7",
  "claims": [
    {
      "text": "The orders table does not currently have an archived column.",
      "verify_sql": "SELECT count(*) FROM information_schema.columns WHERE table_schema = 'public' AND table_name = 'orders' AND column_name = 'archived'",
      "expect": "0"
    },
    {
      "text": "There are approximately 835,616 rows in orders created before 2026-01-01 out of ~5 million total rows.",
      "verify_sql": "SELECT count(*) FROM orders WHERE created_at < '2026-01-01'",
      "expect": "835616"
    }
  ],
  "steps": [
    {
      "sql": "SET lock_timeout = '500ms'",
      "expect": {
        "max_lock_wait_s": "<1"
      }
    },
    {
      "sql": "ALTER TABLE public.orders ADD COLUMN archived boolean NOT NULL DEFAULT false",
      "retries": 10,
      "expect": {
        "table_exists:orders": "==1",
        "max_lock_wait_s": "<5"
      }
    },
    {
      "sql": "SET lock_timeout = '0'",
      "expect": {
        "max_lock_wait_s": "<1"
      }
    },
    {
      "sql": "DO $$\nDECLARE\n  v_min_id integer;\n  v_max_id integer;\n  v_cur integer;\n  v_step integer := 25000;\n  v_rows integer;\n  v_rem_ids integer[];\n  v_id integer;\nBEGIN\n  SELECT min(id), max(id) INTO v_min_id, v_max_id FROM public.orders;\n  IF v_min_id IS NULL THEN\n    RETURN;\n  END IF;\n\n  v_cur := v_min_id;\n  WHILE v_cur <= v_max_id LOOP\n    UPDATE public.orders\n    SET archived = true\n    WHERE id IN (\n      SELECT id FROM public.orders\n      WHERE id >= v_cur AND id < v_cur + v_step\n        AND created_at < '2026-01-01'::timestamptz\n        AND archived = false\n      FOR UPDATE SKIP LOCKED\n    );\n    GET DIAGNOSTICS v_rows = ROW_COUNT;\n    COMMIT;\n    IF v_rows > 0 THEN\n      PERFORM pg_sleep(0.01);\n    END IF;\n    v_cur := v_cur + v_step;\n  END LOOP;\n\n  SELECT array_agg(id) INTO v_rem_ids\n  FROM public.orders\n  WHERE created_at < '2026-01-01'::timestamptz\n    AND archived = false;\n\n  IF v_rem_ids IS NOT NULL THEN\n    FOREACH v_id IN ARRAY v_rem_ids LOOP\n      UPDATE public.orders\n      SET archived = true\n      WHERE id = v_id AND archived = false;\n      COMMIT;\n    END LOOP;\n  END IF;\nEND\n$$",
      "expect": {
        "max_lock_wait_s": "<5",
        "oom_kills": "==0"
      }
    },
    {
      "sql": "VACUUM (ANALYZE) public.orders",
      "expect": {
        "max_lock_wait_s": "<5",
        "oom_kills": "==0"
      }
    },
    {
      "sql": "DO $$\nDECLARE\n  v_unarchived bigint;\n  v_misarchived bigint;\n  v_is_nullable text;\nBEGIN\n  SELECT is_nullable INTO v_is_nullable\n  FROM information_schema.columns\n  WHERE table_schema = 'public' AND table_name = 'orders' AND column_name = 'archived';\n\n  IF v_is_nullable IS DISTINCT FROM 'NO' THEN\n    RAISE EXCEPTION 'orders.archived is missing or nullable (%)', v_is_nullable;\n  END IF;\n\n  SELECT count(*) INTO v_unarchived\n  FROM public.orders\n  WHERE created_at < '2026-01-01'::timestamptz AND archived = false;\n\n  IF v_unarchived <> 0 THEN\n    RAISE EXCEPTION 'Found % unarchived orders before 2026-01-01', v_unarchived;\n  END IF;\n\n  SELECT count(*) INTO v_misarchived\n  FROM public.orders\n  WHERE created_at >= '2026-01-01'::timestamptz AND archived = true;\n\n  IF v_misarchived <> 0 THEN\n    RAISE EXCEPTION 'Found % archived orders on or after 2026-01-01', v_misarchived;\n  END IF;\nEND\n$$",
      "expect": {
        "table_exists:orders": "==1",
        "max_lock_wait_s": "<5"
      }
    }
  ],
  "rehearsal": {
    "workload": "W_prod",
    "minutes": 2,
    "metrics": [
      "p99_rel",
      "max_lock_wait_s",
      "oom_kills",
      "io_util_pct",
      "dead_tuples:orders",
      "rowcount:orders"
    ],
    "thresholds": {
      "p99_rel": "<1.2x",
      "max_lock_wait_s": "<5",
      "oom_kills": "==0",
      "rowcount:orders": ">=5002856"
    }
  },
  "rollback": [
    "SET lock_timeout = '5s'; ALTER TABLE public.orders DROP COLUMN IF EXISTS archived;"
  ],
  "postconditions": [
    "Column orders.archived exists with type boolean, NOT NULL, and default false",
    "All rows in orders with created_at < '2026-01-01' have archived = true",
    "All rows in orders with created_at >= '2026-01-01' have archived = false"
  ],
  "risk": {
    "class_guess": "medium",
    "blast_radius": "orders table DDL lock and ~835k row updates replicated to standby"
  }
}

-> results grid
-> results tables