API Design · Senior · Question 57 of 75

What is request hedging, and when is it appropriate?

1Retrying failed writes immediately
2Sending every request twice from the start
✓Correct answer: Sending a duplicate request after a short delay to another replica and using the first response, for idempotent reads with high tail latency

Explanation

Hedging cuts tail latency at the cost of extra load; never hedge non-idempotent operations.

Further reading

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