Constant Backoff

Resilience Patterns

Meaning

Constant backoff is a simple retry strategy where a fixed delay is inserted between each attempt to recover from a transient failure. It is used when the failure is expected to be short-lived and a constant pause is sufficient to allow the service to recover.

Primary Function

Fault tolerance

Communicative Purpose

Provides a straightforward retry mechanism with a uniform delay to handle intermittent errors without overwhelming the system.

Pattern

retry operation → wait fixed interval → repeat until success or max attempts

Core Structure

delay = constant

Função primária

Fault tolerance

Propósito comunicativo

Provides a straightforward retry mechanism with a uniform delay to handle intermittent errors without overwhelming the system.

Situações de gatilho

Retrying a failed HTTP request to a web API, reconnecting to a database after a temporary network glitch, attempting to read from a flaky sensor.

Contextos

Distributed systems, microservices, cloud services, IoT devices, retry libraries

Padrão

retry operation → wait fixed interval → repeat until success or max attempts

Estrutura central

delay = constant

Slots de substituição

constant: fixed delay duration (e.g., seconds)

Colocados típicos

exponential backoff
jitter
retry limits
circuit breaker

Substituições comuns

exponential backoff (increases delay each attempt)
random jitter (adds variability to avoid thundering herd)

Erros comuns

Using a delay too short, causing overload; using a delay too long, adding unnecessary latency; omitting a maximum retry count.

Similar / contraste

exponential backoff (delay grows exponentially), Fibonacci backoff (delay follows Fibonacci sequence)

Interferências

Coming from networking: may confuse constant backoff with rate limiting, which controls request frequency rather than retry timing.

Família do chunk

exponential backoff
Fibonacci backoff
jitter
retry budget

Nuance

Not ideal for high-load services where repeated retries can worsen congestion; better to use exponential backoff with jitter in such cases.

Efeito pragmático

Enables simple recovery from transient failures without complex logic; prevents immediate retry storms when the delay is appropriately chosen.

Dica de memória

Like waiting a fixed time between knocks on a door.

Nota

Often paired with a maximum retry limit to avoid infinite loops.

Upgrade path

Exponential backoff with jitter

Frequência: MediumFormulaicidade: FlexibleTipo de construção: retry algorithmPrioridade de aquisição: Active recallPrioridade de output: BothTag de espaçamento: Medium-term

Examples

import time import requests def fetch_with_constant_backoff(url, max_retries=5, delay=2): for attempt in range(1, max_retries + 1): try: response = requests.get(url) response.raise_for_status() return response.json() except requests.RequestException: if attempt == max_retries: raise time.sleep(delay) data = fetch_with_constant_backoff("https://api.example.com/data")

import time import psycopg2 from psycopg2 import OperationalError def connect_with_constant_backoff(dsn, max_retries=3, delay=3): for attempt in range(1, max_retries + 1): try: conn = psycopg2.connect(dsn) return conn except OperationalError: if attempt == max_retries: raise time.sleep(delay) conn = connect_with_constant_backoff("dbname=mydb user=app")

import time import random def read_sensor_with_constant_backoff(read_func, max_attempts=4, delay=1): for attempt in range(1, max_attempts + 1): value = read_func() if value is not None: return value if attempt == max_attempts: raise RuntimeError("Sensor read failed after retries") time.sleep(delay) def mock_sensor(): # Simulate flaky sensor: succeeds 30% of the time return random.random() if random.random() < 0.3 else None sensor_value = read_sensor_with_constant_backoff(mock_sensor)