t8y2/dbx · error · TimeoutError

RSS probe timed out: {'; '.join(stderr_lines)}

Error message

RSS probe timed out: {'; '.join(stderr_lines)}

What it means

measure_rss() waits up to BENCH_READY_TIMEOUT (default 30s) for the probe's stdout to emit a JSON line with ready=true. If the deadline passes without a ready signal, the for/else raises TimeoutError listing accumulated stderr lines — the probe is alive but never reported readiness.

Source

Thrown at agents/drivers/iotdb/bench/run.py:159

        assert process.stderr is not None
        stderr_lines.extend(line.rstrip() for line in process.stderr)

    threading.Thread(target=drain_stderr, daemon=True).start()
    try:
        assert process.stdout is not None
        deadline = time.monotonic() + env_float("BENCH_READY_TIMEOUT", 30.0)
        while time.monotonic() < deadline:
            line = process.stdout.readline()
            if line == "" and process.poll() is not None:
                raise RuntimeError(f"RSS probe exited early: {'; '.join(stderr_lines)}")
            try:
                payload = json.loads(line)
            except json.JSONDecodeError:
                continue
            if payload.get("ready") is True:
                break
        else:
            raise TimeoutError(f"RSS probe timed out: {'; '.join(stderr_lines)}")
        time.sleep(0.2)
        completed = subprocess.run(
            ["ps", "-o", "rss=", "-p", str(process.pid)],
            text=True,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            check=True,
        )
        return float(completed.stdout.strip())
    finally:
        process.terminate()
        try:
            process.wait(timeout=5)
        except subprocess.TimeoutExpired:
            process.kill()
            process.wait(timeout=5)

View on GitHub (pinned to c0390bff16)

Solutions

1. Increase the timeout: export BENCH_READY_TIMEOUT=120
2. Ensure the probe flushes stdout (print(..., flush=True)) when printing the ready JSON
3. Verify the readiness payload key is exactly ready with value true in the tool version in use
4. Check stderr in the message for hints the probe is stuck (waiting on a resource/port)
5. Run the probe manually to observe how long readiness actually takes

Example fix

// before
export BENCH_READY_TIMEOUT=30  # TimeoutError: RSS probe timed out
// after
export BENCH_READY_TIMEOUT=120

def preflight_ready_latency(cmd: list[str], env: dict) -> float:
    start = time.monotonic()
    # time a manual run to learn real readiness latency, then size the timeout
    subprocess.run(cmd, env=env, capture_output=True, text=True)
    return time.monotonic() - start  # set BENCH_READY_TIMEOUT well above this

try:
    rss = measure_rss(command, environment)
except TimeoutError as e:
    print(f"probe never reported ready:\n{e}")
    print("retrying with a larger timeout")
    environment["BENCH_READY_TIMEOUT"] = "120"
    rss = measure_rss(command, environment)

When it happens

Trigger: The probe keeps running but never prints {"ready": true} within the deadline: slow startup, readiness line sent to stderr, JSON payloads that never include ready=true, or stdout buffering delaying the line past the timeout.

Common situations: BENCH_READY_TIMEOUT too short for a cold-starting JVM/database; tool version emits a different readiness key; output block-buffered because stdout is a pipe without flush; probe stuck initializing (e.g. waiting on its own dependency).

Understand the failure class

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

• timed out waiting for agent readiness
• timed out waiting for agent readiness
• timed out during {method}
• timed out waiting for agent readiness
• agent exited before ready

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/8b6948329ff443d1. Report an issue: GitHub.