In distributed systems, what is the "thundering herd" problem and what is a common mitigation?
Correct! Well done.
Incorrect.
The correct answer is C) Many clients waking up and hitting a resource at once — e.g. when a hot cache key expires — overwhelming it; mitigated with jittered expiration, request coalescing, or a lock so only one caller repopulates it
Correct Answer
Many clients waking up and hitting a resource at once — e.g. when a hot cache key expires — overwhelming it; mitigated with jittered expiration, request coalescing, or a lock so only one caller repopulates it
When a hot cache entry expires, every concurrent request can simultaneously fall through to the origin (database or backend service), causing a spike that can crash it. Adding random jitter to expiration times, coalescing duplicate in-flight requests, or locking so only one request recomputes the value are standard mitigations.