Retrys

Retrys, sometimes written as retrys in informal contexts, refer to the repeated attempts to perform a task after a failed initial attempt. More commonly, the term retries or retry attempts are used in documentation and practice. Retries are a core concept in fault-tolerant systems and distributed architectures, designed to cope with transient faults such as temporary network outages, brief service unavailability, or momentary resource contention.

A typical retry mechanism uses a policy that dictates when and how to retry. Key elements include the maximum number of attempts, a timeout or deadline for the overall operation, and a backoff strategy that spaces retries over time. Backoff strategies range from fixed intervals to exponential backoff, often paired with jitter to prevent synchronized retries across multiple clients. Some implementations distinguish retryable errors (for example, certain 5xx HTTP responses) from non-retryable ones (such as client errors 4xx).

Important considerations include idempotency, ensuring that repeated attempts do not cause unintended side effects or data corruption. Observability is also crucial: clear logging, metrics on success and failure rates, and alerting help operators assess whether retries indicate a problem or are masking an underlying fault. Retries can improve reliability but may increase latency and resource usage; if overused, they can contribute to cascading failures or thundering herd problems.

Use cases span network requests, database operations, and messaging systems, where transient failures are possible. Complementary patterns include circuit breakers and timeouts to provide a balanced strategy for resilience and performance.