Retry mechanisms are crucial for system self-healing capabilities in handling failures caused by network issues, service overload, or unstable interfaces.
Designing retries poorly can lead to request storms, cascading failures, and incidents, while well-designed retries improve success rates and user experience.
Common retry strategies discussed include Brute-force Looping, Spring Retry, Resilience4j, MQ Queue, Scheduled Task, Two-Phase Commit, and Distributed Lock mechanisms.
Brute-force Looping demonstrated issues with fixed delay and retrying non-transient errors, recommending random delays and filtering out non-retriable exceptions.
Spring Retry offers declarative annotations, exponential backoff, and circuit breaker integration, providing clean code and automatic retry interval adjustments.
Resilience4j is suitable for complex systems, offering custom backoff algorithms, circuit breaker strategies, and multi-layer protection, resulting in significant improvements in API timeout rates.
MQ Queue is used for high-concurrency asynchronous scenarios, where messages are retried with preset delays and moved to a dead letter queue after reaching max retries.
Scheduled Tasks are beneficial for batch processing tasks that allow retries, such as file imports, providing a scheduled job approach for handling failures.
Two-Phase Commit is recommended for strict data consistency requirements like fund transfers, involving recording transactions, remote API calls, and compensation tasks for retrying transactions.
Distributed Locks are useful in environments requiring idempotency, like flash sales, utilizing Redis + Lua for acquiring locks and handling retries safely in multi-threaded scenarios.
Choosing the appropriate retry mechanism is essential for system stability, emphasizing the importance of balancing offense and defense strategies based on business requirements.