Backend & systems·Concurrency and coordination
the low-priority job never runs because higher-priority work keeps arriving and taking the resource first.
Starvation
A process being indefinitely denied a resource it needs while others make progress. It is the failure mode of unfair scheduling and priority queues. Aging — raising priority with wait time — is the standard fix, and its absence is why the cleanup job that runs "when there is spare capacity" never runs.