I have a job which is calling a spring boot application end points and getting some data from it. I have roughly 400,000,00 data points which are being sent to end point using Map function.  I am running application on Yarn and I have assigned 300+ executors each having 8 gigs memory.  Everything runs smoothly, I can see requests coming and going on spring boot application.  All executors finish their job in time but a couple of them ( mostly 1 or sometimes 2-5 ) keep on waiting and doing absolutely nothing. And that last step never finishes.  Their thread dump shows they are waiting for some threads.  I have tried to turn on dynamic allocation but still having the same problem.    What could be the issue?     ... View more