Re: Problem with Summerization

[rostami]

Exactly.
Updating flink solved my problem.
Thanks.

Quoting Greg Hogan <c...@greghogan.com>:

The stacktrace indicates this may be a bug that was fixed for Flink 1.2:

    [FLINK-4624] [gelly] Support null values in Graph Summarization

    * Bug was caused by serializers that cannot handle null values (e.g.
Long)
    * VertexGroupItem now uses Either<NullValue, VV> instead of VV
    * Generalized test cases
    * Added tests for vertex/edge values of type Long
    * Replaced Guava Lists.newArrayList() with new ArrayList<>()


On Wed, Jun 28, 2017 at 2:22 AM, <rost...@informatik.uni-leipzig.de> wrote:

Hi,

these are the outputs for a small test graph:

gellyGraph.getVertices().print();
(000000000000000000000003,9)
(000000000000000000000007,9)
(000000000000000000000005,5)
(000000000000000000000001,9)
(000000000000000000000006,9)
(000000000000000000000000,9)
(000000000000000000000004,9)
(000000000000000000000002,2)
(000000000000000000000008,8)
(000000000000000000000009,9)
(00000000000000000000000a,10)


gellyGraph.getEdges().print();
(000000000000000000000002,000000000000000000000001,(null))
(000000000000000000000006,000000000000000000000003,(null))
(000000000000000000000000,000000000000000000000001,(null))
(000000000000000000000008,000000000000000000000003,(null))
(000000000000000000000005,000000000000000000000006,(null))
(000000000000000000000009,000000000000000000000000,(null))
(000000000000000000000009,00000000000000000000000a,(null))
(000000000000000000000005,00000000000000000000000a,(null))
(000000000000000000000009,000000000000000000000004,(null))
(000000000000000000000005,000000000000000000000006,(null))
(000000000000000000000005,000000000000000000000007,(null))
(000000000000000000000009,000000000000000000000000,(null))
(000000000000000000000006,000000000000000000000007,(null))
(000000000000000000000004,000000000000000000000007,(null))
(000000000000000000000008,000000000000000000000007,(null))
(000000000000000000000002,000000000000000000000000,(null))
(000000000000000000000009,000000000000000000000001,(null))
(000000000000000000000005,000000000000000000000003,(null))
(000000000000000000000008,000000000000000000000006,(null))
(000000000000000000000000,000000000000000000000004,(null))
(000000000000000000000002,000000000000000000000004,(null))
(000000000000000000000007,000000000000000000000004,(null))
(000000000000000000000007,000000000000000000000006,(null))
(000000000000000000000004,000000000000000000000000,(null))

g.getVertices().print(); //correct results
(000000000000000000000005,(5,1))
(000000000000000000000002,(2,1))
(000000000000000000000008,(8,1))
(000000000000000000000004,(9,7))
(00000000000000000000000a,(10,1))

g.getEdges.print(); //error!!

As I said, I also tested when edges have values other than null
and the same problem appears.

Regards,
Ali


Quoting Greg Hogan <c...@greghogan.com>:

Hi Ali,

Could you print and include a gellyGraph which results in this error.

Greg


On Jun 27, 2017, at 2:48 PM, rost...@informatik.uni-leipzig.de wrote:

Dear All,

I do not understand what the error in the following code can be?

Graph<GradoopId, Long, NullValue> gellyGraph = ...

Graph<GradoopId,Summarization.VertexValue<Long>,
Summarization.EdgeValue<NullValue>> g =
                           gellyGraph.run(new Summarization<GradoopId,
Long, NullValue>());

g.getVertices().print(); //this one works fine
g.getEdges().print();    //this one gives the following error

...
org.apache.flink.types.NullFieldException: Field 2 is null, but
expected to hold a value.
        at org.apache.flink.api.java.typeutils.runtime.TupleSerializer.
serialize(TupleSerializer.java:126)
        at org.apache.flink.api.java.typeutils.runtime.TupleSerializer.
serialize(TupleSerializer.java:30)
        at org.apache.flink.runtime.plugable.SerializationDelegate.
write(SerializationDelegate.java:56)
        at org.apache.flink.runtime.io.network.api.serialization.Spanni
ngRecordSerializer.addRecord(SpanningRecordSerializer.java:83)
        at org.apache.flink.runtime.io.network.api.writer.RecordWriter.
emit(RecordWriter.java:85)
        at org.apache.flink.runtime.operators.shipping.OutputCollector.
collect(OutputCollector.java:65)
        at org.apache.flink.runtime.operators.util.metrics.CountingColl
ector.collect(CountingCollector.java:35)
        at org.apache.flink.graph.library.Summarization$VertexGroupRedu
cer.reduce(Summarization.java:318)
        at org.apache.flink.runtime.operators.GroupReduceDriver.run(
GroupReduceDriver.java:131)
        at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.
java:486)
        at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTas
k.java:351)
        at org.apache.flink.runtime.taskmanager.Task.run(Task.java:584)
        at java.lang.Thread.run(Thread.java:748)

I also tried with different types for EdgeValue. The same error appears.
When I look at the result vertices, everything looks fine.
But the result edges has this problem.

Any idea?

Regards,
Ali