# Five hundred workers call a downstream API every minute

Canonical URL: <https://datadriven.io/problems/five-hundred-workers-call-a-downstream-api-every-minute-a-b-f2a8e7bb>

Domain: Pipeline Design · Difficulty: medium

## Problem

Five hundred workers call a downstream API every minute. A brief latency spike caused all 500 to time out at the same instant. Every worker retries on a fixed one-second sleep, so 500 retries arrive at the downstream simultaneously one second later. The retries themselves become the load. The section names this a thundering herd. Find the herd by replacing the fixed-delay retry with one whose name states both halves of the section's fix: a backoff schedule (wait longer between successive retries) and a jitter strategy (random offset that desynchronizes the wave).

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