Shannon Carey created FLINK-4803:
------------------------------------

             Summary: Job Cancel can hang forever waiting for 
OutputFormat.close()
                 Key: FLINK-4803
                 URL: https://issues.apache.org/jira/browse/FLINK-4803
             Project: Flink
          Issue Type: Bug
    Affects Versions: 1.1.1
            Reporter: Shannon Carey


If the Flink job uses a badly-behaved OutputFormat (in this example, a 
HadoopOutputFormat containing a CqlBulkOutputFormat), where the close() method 
blocks forever, it is impossible to cancel the Flink job even though the 
blocked thread would respond to an interrupt. The stack traces below show the 
state of the important threads when a job is canceled and the OutputFormat is 
blocking forever inside of close().

I suggest that `DataSinkTask.cancel()` method be updated to add a timeout on 
`this.format.close()`. When the timeout is reached, the Task thread should be 
interrupted.

{code}
   java.lang.Thread.State: BLOCKED (on object monitor)
        at 
org.apache.flink.api.java.hadoop.mapred.HadoopOutputFormatBase.close(HadoopOutputFormatBase.java:158)
        - waiting to lock <0x00000006bae5f788> (a java.lang.Object)
        at 
org.apache.flink.runtime.operators.DataSinkTask.cancel(DataSinkTask.java:268)
        at 
org.apache.flink.runtime.taskmanager.Task$TaskCanceler.run(Task.java:1149)
        at java.lang.Thread.run(Thread.java:745)

"DataSink 
(org.apache.flink.api.scala.hadoop.mapred.HadoopOutputFormat@13bf17a2) (2/5)" 
#6410 daemon prio=5 os_prio=0 tid=0x00007fb7e79a4800 nid=0x2ad8 waiting on 
condition [0x00007fb7bdf78000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x00000006c5ab5e20> (a 
java.util.concurrent.SynchronousQueue$TransferStack)
        at 
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
        at 
java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(SynchronousQueue.java:460)
        at 
java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:362)
        at 
java.util.concurrent.SynchronousQueue.offer(SynchronousQueue.java:895)
        at 
org.apache.cassandra.io.sstable.SSTableSimpleUnsortedWriter.put(SSTableSimpleUnsortedWriter.java:194)
        at 
org.apache.cassandra.io.sstable.SSTableSimpleUnsortedWriter.sync(SSTableSimpleUnsortedWriter.java:180)
        at 
org.apache.cassandra.io.sstable.SSTableSimpleUnsortedWriter.close(SSTableSimpleUnsortedWriter.java:156)
        at 
org.apache.cassandra.io.sstable.CQLSSTableWriter.close(CQLSSTableWriter.java:275)
        at 
org.apache.cassandra.hadoop.AbstractBulkRecordWriter.close(AbstractBulkRecordWriter.java:133)
        at 
org.apache.cassandra.hadoop.AbstractBulkRecordWriter.close(AbstractBulkRecordWriter.java:126)
        at 
org.apache.flink.api.java.hadoop.mapred.HadoopOutputFormatBase.close(HadoopOutputFormatBase.java:158)
        - locked <0x00000006bae5f788> (a java.lang.Object)
        at 
org.apache.flink.runtime.operators.DataSinkTask.invoke(DataSinkTask.java:234)
        at org.apache.flink.runtime.taskmanager.Task.run(Task.java:584)
        at java.lang.Thread.run(Thread.java:745)
{code}



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