I think Fabian looked into this a while back... @Fabian, do you have any insights what causes this?
On Sat, Apr 25, 2015 at 7:46 PM, Vasiliki Kalavri <vasilikikala...@gmail.com > wrote: > Hi, > > I actually ran into this problem again with a different algorithm :/ > Same exception and it looks like getMatchFor() in CompactingHashTable > returns a null record. > Not sure why or why the annotation prevents this from happening. Any > insight is highly welcome :-) > > Shall I open an issue so that we don't forget about this? > > -Vasia. > > > On 4 April 2015 at 14:44, Vasiliki Kalavri <vasilikikala...@gmail.com> > wrote: > > > 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 <fhue...@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 <vasilikikala...@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 <fhue...@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" < > >> vasilikikala...@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. > >> > > > > >> > > > >> > > >> > > > > >
