Thundering Herd
A contention pattern in which many waiting workers or clients wake or retry simultaneously for the same event or resource, creating a burst of redundant work.
Performance Context
A thundering herd occurs when many waiters or clients react to the same trigger at nearly the same time, creating a burst of redundant CPU work, lock contention, reconnect attempts, or downstream traffic. Cache refresh and retry storms are common examples.
Contention Boundary
High traffic alone is not a thundering herd; synchronized behavior caused by one event is the defining feature. Jitter, request coalescing, and single-flight mechanisms can spread or eliminate redundant work.