Thank you very much for taking the time to respond.

My apologies, but at the moment I don't have an example that 
I feel comfortable posting.  Frankly, I've been struggling with variants
of this for the last two weeks and probably won't be able to work on 
this particular issue for a few days.

However, I am intrigued by your comment.  You mention "when I close
the fs object inside map/mapPartition etc."  Where else can one close the
object?  If I don't close it, the output file is generally truncated.

Again, the code seems to work for  a few hundred files, then I get these
weird errors. Is this something subtle related to the shipping of the closure that
I'm not aware of?  

Can you give a general idea of how you handled this?
Is it necessary to create a custom OutputFormat class?
I was looking at the OutputFormat code and it looks like it also creates
an "fs" object and starts writing, but perhaps there is some 
subtle difference in the context?

Thank you.


From: Akhil Das <>
To: Michael Albert <>
Cc: "" <>
Sent: Monday, January 5, 2015 1:21 AM
Subject: Re: a vague question, but perhaps it might ring a bell

What are you trying to do? Can you paste the whole code? I used to see this sort of Exception when i close the fs object inside map/mapPartition etc.

Best Regards

On Mon, Jan 5, 2015 at 6:43 AM, Michael Albert <> wrote:

So, I think I have data saved so that each partition (part-r-00000, etc)
is exactly what I wan to translate into an output file of a format not related to 

I believe I've figured out how to tell Spark to read the data set without re-partitioning (in 
another post I mentioned this -- I have a non-splitable InputFormat).

I do something like
   mapPartitionWithIndex( (partId, iter) => 
           conf = new Configuration()
           fs = Filesystem.get(conf)
           strm = fs.create(new Path(...))
            //  write data to stream
          strm.close() // in finally block }

This runs for a few hundred input files (so each executors sees 10's of files),
and it chugs along nicely, then suddenly everything shuts down.
I can restart (telling it to skip the partIds which it has already completed), and it
chugs along again for a while (going past the previous stopping point) and again dies.

I am a t a loss.  This work for the first 10's of files (so it runs for about 1hr) then quits,
and I see no useful error information (no Exceptions except the stuff below.
I'm not shutting it down.

Any idea what I might check? I've bumped up the memory multiple times (16G currently)
and fiddled with increasing other parameters.

Exception in thread "main" org.apache.spark.SparkException: Job cancelled because SparkContext was shut down
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$cleanUpAfterSchedulerStop$1.apply(DAGScheduler.scala:694)
    at org.apache.spark.scheduler.DAGScheduler$$anonfun$cleanUpAfterSchedulerStop$1.apply(DAGScheduler.scala:693)
    at scala.collection.mutable.HashSet.foreach(HashSet.scala:79)
    at org.apache.spark.scheduler.DAGScheduler.cleanUpAfterSchedulerStop(DAGScheduler.scala:693)
    at org.apache.spark.scheduler.DAGSchedulerEventProcessActor.postStop(DAGScheduler.scala:1399)
    at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:262)