Noticed this with a couple of pig scripts which were not behaving well (AM close to OOM, etc) and even with some that were running fine. Pig calls Tezclient.stop() in shutdown hook. Ctrl+C to the pig script either exits immediately or is hung. In both cases it either takes a long time for the yarn application to go to KILLED state. Many times I just end up calling yarn application -kill separately after waiting for 5 mins or more for it to get killed.