Major Description
It's found that a Spark application is leaked when user cancels query and closes the session while Hive is waiting for remote driver to connect back. This is found for asynchronous query execution, but seemingly equally applicable for synchronous submission when session is abruptly closed. The leaked Spark application that runs Spark driver connects back to Hive successfully and run for ever (until HS2 restarts), but receives no job submission because the session is already closed. Ideally, Hive should rejects the connection from the driver so the driver will exist.