I've built a hybrid task queue/process supervisor on top of SQL. Classical task queues like Celery didn't exactly fit our use case: a single process could run for hours or days, but in case of a node failing, it must be resurrected elsewhere as soon as possible (within seconds). I didn't have the time to re-architect everything for Kubernetes, or rewrite half the product in Erlang; so I built that weird thing. It's been super stable, running mission critical code, and making us money - for several years now.