[jira] [Created] (SPARK-2034) KafkaInputDStream doesn't close resources and may prevent JVM shutdown

["Sean Owen (JIRA)" <ji...@apache.org>]

Sean Owen created SPARK-2034:
--------------------------------

             Summary: KafkaInputDStream doesn't close resources and may prevent JVM shutdown
                 Key: SPARK-2034
                 URL: https://issues.apache.org/jira/browse/SPARK-2034
             Project: Spark
          Issue Type: Bug
          Components: Streaming
    Affects Versions: 1.0.0
            Reporter: Sean Owen


Tobias noted today on the mailing list:

{quote}
I am trying to use Spark Streaming with Kafka, which works like a
charm -- except for shutdown. When I run my program with "sbt
run-main", sbt will never exit, because there are two non-daemon
threads left that don't die.

I created a minimal example at
<https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-kafkadoesntshutdown-scala>.
It starts a StreamingContext and does nothing more than connecting to
a Kafka server and printing what it receives. Using the `future { ...
}` construct, I shut down the StreamingContext after some seconds and
then print the difference between the threads at start time and at end
time. The output can be found at
<https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-output1>.
There are a number of threads remaining that will prevent sbt from
exiting.

When I replace `KafkaUtils.createStream(...)` with a call that does
exactly the same, except that it calls `consumerConnector.shutdown()`
in `KafkaReceiver.onStop()` (which it should, IMO), the output is as
shown at <https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-output2>.

Does anyone have *any* idea what is going on here and why the program
doesn't shut down properly? The behavior is the same with both kafka
0.8.0 and 0.8.1.1, by the way.
{quote}

Something similar was noted last year:

http://mail-archives.apache.org/mod_mbox/spark-dev/201309.mbox/%3C1380220041.2428.YahooMailNeo@web160804.mail.bf1.yahoo.com%3E 

KafkaInputDStream doesn't close ConsumerConnector in onStop(), and does not close the Executor it creates. The latter leaves non-daemon threads and can prevent the JVM from shutting down even if streaming is closed properly.



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