Level 3 · Architecture
Retries, idempotency and backpressure
A downstream service slows down. Every caller retries. The retries multiply the load, which slows it further. Retry logic written without thought is the most reliable way to turn a blip into an outage.
Chapters
- How retries multiply system loadUncoordinated client retries amplify downstream database and service failures, transforming minor network glitches into permanent system outages.
- How idempotency handles duplicatesSince network failures make duplicate messages inevitable, applications must use idempotency keys and conditional writes to ensure safe execution.