Why aren't you idempotent?
https://lightfoot.dev/why-arent-you-idempotent/?utm_source=bonobopress&utm_medium=newsletter&utm_campaign=1804 Why Aren't You Idempotent? Idempotency doesn’t get the attention it deserves. It enables a distributed system to be both resilient and performant. If, like us, you’re building low-latency APIs and face significant penalties for breaching SLAs, this article may be worth your time. What is idempotency? Idempotency is the quality of an action Very good review about some techniques to achieve idempotency.
One interesting insight is the performance implications of idempotency. It is quite known that an idempotent action is more resilient, since it can be retired safely, but the article goes beyond explaining how can it also improve latency by hedging requests:
Per Jeff Dean in The Tail at Scale, one of the most effective ways to curb latency variability is to hedge your requests, which means to send it to many replicas. This is very similar to retrying on a timeout (or other error), except you're being more proactive and typically hedge after a delay much shorter than your configured timeout.
Hedging comes with the same precondition of idempotency as many replicas could be processing the request in parallel.