Advantage of using ThreadPool in Hystrix

Question

What is the advantage of using threadpool in Hystrix? Suppose we are calling a third party service ,when we call a service or DB that thread goes into waiting state than what is the use of keep creating thread for each call?

So,I mean how short circuited(Threadpooled) method is batter then normal(non short circuited) method?

Answer 1

Lets say when a remote service(any service) is started to respond slowly, but a typical application(service which is making call to remote service) will still continue to call that remote service. So short circuited(Threadpooled) method helps you build a Defensive system in this particular case.

As calling service does not know if the remote service is healthy or not and new threads are spawned every time a request comes in. This will cause threads on an already struggling server to be used.

We don't want this to happen as we need these threads for other remote calls or processes running on our server and we also want to avoid CPU utilization spiking up. so this prevents resources from becoming blocked if latency occurs. Also Bounded thread pool also gives some breathing room for downstream services to recover.

For detail : ThreadPool in Hystrix