Hi Chesnay,

Heh, I have discovered that if I do not restart Flink after running my
original problematic script, then similar issues will manifest themselves
in other otherwise working scripts. I haven't been able to completely
narrow down the problem, but I promise this new script will have a
ClassCastException that is completely reproducible. :)
https://gist.github.com/GEOFBOT/abb7f81030aab160e6908093ebaa3b4a

Thanks,
Geoffrey

On Wed, Sep 28, 2016 at 9:16 AM Chesnay Schepler <ches...@apache.org> wrote:

> Hello Geoffrey,
>
> this one works for me as well :D
>
> Regards,
> Chesnay
>
> On 28.09.2016 05:38, Geoffrey Mon wrote:
> > Hello Chesnay,
> >
> > Thank you for your help. After receiving your message I recompiled my
> > version of Flink completely, and both the NullPointerException listed in
> > the TODO and the ClassCastException with the join operation went away.
> > Previously, I had been only recompiling the modules of Flink that had
> been
> > changed to save time using "mvn clean install -pl :module" and apparently
> > that may have been causing some of my issues.
> >
> > Now, the problem is more clear: when a specific group reduce function in
> my
> > research project plan file is used within an iteration, I get a
> > ClassCastException exception:
> > Caused by: java.lang.ClassCastException:
> > org.apache.flink.api.java.tuple.Tuple2 cannot be cast to [B
> > at
> >
> org.apache.flink.api.common.typeutils.base.array.BytePrimitiveArraySerializer.serialize(BytePrimitiveArraySerializer.java:31)
> > at
> > org.apache.flink.runtime.iterative.io
> .WorksetUpdateOutputCollector.collect(WorksetUpdateOutputCollector.java:58)
> > at
> >
> org.apache.flink.runtime.operators.util.metrics.CountingCollector.collect(CountingCollector.java:35)
> > at
> >
> org.apache.flink.python.api.streaming.data.PythonReceiver.collectBuffer(PythonReceiver.java:96)
> > at
> >
> org.apache.flink.python.api.streaming.data.PythonStreamer.streamBufferWithoutGroups(PythonStreamer.java:272)
> > at
> >
> org.apache.flink.python.api.functions.PythonMapPartition.mapPartition(PythonMapPartition.java:54)
> > at
> >
> org.apache.flink.runtime.operators.MapPartitionDriver.run(MapPartitionDriver.java:103)
> > at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:486)
> > at
> >
> org.apache.flink.runtime.iterative.task.AbstractIterativeTask.run(AbstractIterativeTask.java:146)
> > at
> >
> org.apache.flink.runtime.iterative.task.IterationTailTask.run(IterationTailTask.java:107)
> > at
> org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:351)
> > at org.apache.flink.runtime.taskmanager.Task.run(Task.java:591)
> > at java.lang.Thread.run(Thread.java:745)
> >
> > I'm not sure why this is causing an exception, and I would greatly
> > appreciate any assistance. I've revised the barebones error-causing plan
> > file to focus on this new error source:
> > https://gist.github.com/GEOFBOT/abb7f81030aab160e6908093ebaa3b4a
> > The group reduce function in question seems to work just fine outside of
> > iterations. I have organized the commits and pushed to a new branch to
> make
> > it easier to test and hopefully review soon:
> > https://github.com/GEOFBOT/flink/tree/new-iterations
> >
> > Cheers,
> > Geoffrey
> >
> > On Mon, Sep 26, 2016 at 6:32 AM Chesnay Schepler <ches...@apache.org>
> wrote:
> >
> >> Hello Geoffrey,
> >>
> >> i could not reproduce this issue with the commits and plan you provided.
> >>
> >> I tried out both the FLINK-4098 and bulk-iterations branches (and
> >> reverted back to the specified commits) and built Flink from scratch.
> >>
> >> Could you double check that the code you provided produces the error?
> >> Also, which OS/python version are you using?
> >>
> >> Regards,
> >> Chesnay
> >>
> >> On 20.09.2016 11:13, Chesnay Schepler wrote:
> >>> Hello,
> >>>
> >>> I'll try to take a look this week.
> >>>
> >>> Regards,
> >>> Chesnay
> >>>
> >>> On 20.09.2016 02:38, Geoffrey Mon wrote:
> >>>> Hello all,
> >>>>
> >>>> I have recently been working on adding bulk iterations to the Python
> >>>> API of
> >>>> Flink in order to facilitate a research project I am working on. The
> >>>> current changes can be seen in this GitHub diff:
> >>>>
> >>
> https://github.com/apache/flink/compare/master...GEOFBOT:e8c9833b43675af66ce897da9880c4f8cd16aad0
> >>>>
> >>>> This implementation seems to work for, at least, simple examples,
> >>>> such as
> >>>> incrementing numbers in a data set. However, with the transformations
> >>>> required for my project, I get an exception
> >>>> "java.lang.ClassCastException:
> >>>> [B cannot be cast to org.apache.flink.api.java.tuple.Tuple" thrown
> >>>> from the
> >>>> deserializers called by
> >>>>
> org.apache.flink.python.api.streaming.data.PythonReceiver.collectBuffer.
> >>>> I've created the following simplified Python plan by stripping down my
> >>>> research project code to the problem-causing parts:
> >>>> https://gist.github.com/GEOFBOT/abb7f81030aab160e6908093ebaa3b4a
> >>>>
> >>>> I have been working on this issue but I don't have any ideas on what
> >>>> might
> >>>> be the problem. Perhaps someone more knowledgeable about the interior
> of
> >>>> the Python API could kindly help?
> >>>>
> >>>> Thank you very much.
> >>>>
> >>>> Geoffrey Mon
> >>>>
> >>>
> >>
>
>

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