flink-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Vasiliki Kalavri <vasilikikala...@gmail.com>
Subject Re: NullPointerException in DeltaIteration when no ForwardedFileds annotation
Date Sat, 04 Apr 2015 12:44:31 GMT
Hi Fabian,

thanks for looking into this.
Let me know if there's anything I can do to help!

Cheers,
V.

On 3 April 2015 at 22:31, Fabian Hueske <fhueske@gmail.com> wrote:

> Thanks for the nice setup!
> I could easily reproduce the exception you are facing.
> But that's the only good news so far :-(
>
> I checked the plans and both are valid and should compute the correct
> result for the program.
> The split-of solution set delta is required because the it needs to be
> repartitioned (without the annotation, the optimizer does not know that it
> is in fact already correctly partitioned). One thing that made me a bit
> suspicious is that the solution set delta partitioning is marked with a
> Pipeline-Breaker. The pipeline breaker shouldn't make a semantic
> difference, but I am not sure if it is really required and also that part
> of the codebase was recently worked on.
>
> So, a closer look and more debugging is necessary to figure out what not
> working correctly here...
>
>
> 2015-04-03 14:14 GMT+02:00 Vasiliki Kalavri <vasilikikalavri@gmail.com>:
>
> > Hi Fabian,
> >
> > I am using the dblp co-authorship dataset from SNAP:
> > http://snap.stanford.edu/data/com-DBLP.html
> > I also pushed my slightly modified version of ConnectedComponents, here:
> > https://github.com/vasia/flink/tree/cc-test. It basically generates the
> > vertex dataset from the edges, so that you don't need to create it
> > separately.
> > The annotation that creates the error is in line #172.
> >
> > Thanks a lot :))
> >
> > -Vasia.
> >
> >
> > On 3 April 2015 at 13:09, Fabian Hueske <fhueske@gmail.com> wrote:
> >
> > > That looks pretty much like a bug.
> > >
> > > As you said, fwd fields annotations are optional and may improve the
> > > performance of a program, but never change its semantics (if set
> > > correctly).
> > >
> > > I'll have a look at it later.
> > > Would be great if you could provide some data to reproduce the bug.
> > > On Apr 3, 2015 12:48 PM, "Vasiliki Kalavri" <vasilikikalavri@gmail.com
> >
> > > wrote:
> > >
> > > > Hello to my squirrels,
> > > >
> > > > I've been getting a NullPointerException for a DeltaIteration program
> > I'm
> > > > trying to implement and I could really use your help :-)
> > > > It seems that some of the input Tuples of the Join operator that I'm
> > > using
> > > > to create the next workset / solution set delta are null.
> > > > It also seems that adding ForwardedFields annotations solves the
> issue.
> > > >
> > > > I managed to reproduce the behavior using the ConnectedComponents
> > > example,
> > > > by removing the "@ForwardedFieldsFirst("*")" annotation from
> > > > the ComponentIdFilter join.
> > > > The exception message is the following:
> > > >
> > > > Caused by: java.lang.NullPointerException
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.examples.java.graph.ConnectedComponents$ComponentIdFilter.join(ConnectedComponents.java:186)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.examples.java.graph.ConnectedComponents$ComponentIdFilter.join(ConnectedComponents.java:1)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.operators.JoinWithSolutionSetSecondDriver.run(JoinWithSolutionSetSecondDriver.java:198)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.iterative.task.AbstractIterativePactTask.run(AbstractIterativePactTask.java:139)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.iterative.task.IterationIntermediatePactTask.run(IterationIntermediatePactTask.java:92)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
> > > > at
> > > >
> > > >
> > >
> >
> org.apache.flink.runtime.execution.RuntimeEnvironment.run(RuntimeEnvironment.java:217)
> > > > at java.lang.Thread.run(Thread.java:745)
> > > >
> > > > I get this error locally with any sufficiently big dataset (~10000
> > > nodes).
> > > > When the annotation is in place, it works without problem.
> > > > I also generated the optimizer plans for the two cases:
> > > > - with annotation (working):
> > > > https://gist.github.com/vasia/4f4dc6b0cc6c72b5b64b
> > > > - without annotation (failing):
> > > > https://gist.github.com/vasia/086faa45b980bf7f4c09
> > > >
> > > > After visualizing the plans, the main difference I see is that in the
> > > > working case, the next workset node and the solution set delta nodes
> > are
> > > > merged, while in the failing case they are separate.
> > > >
> > > > Shouldn't this work with and without annotation (but be more
> efficient
> > > with
> > > > the annotation in place)? Or am I missing something here?
> > > >
> > > > Thanks in advance for any help :))
> > > >
> > > > Cheers,
> > > > - Vasia.
> > > >
> > >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message