Re: Kryo StackOverflowError

Sun, 10 Apr 2016 11:37:28 -0700 

Hi,
I also had this problem and solved it.
In my case I had multiple objects which are created via anonymous classes. When I broadcasted these objects, the serializer tried to serialize the objects and for that it tried to serialize the anonymous classes. This caused the problem. 

For example,

class A{

 def createObjects() : Array[Object]{
           objects
        for{
            object = new Class{
            ...
            }
            objects.add(object)
        }
        return objects
    }
}


It tried to serialize "new Class". For that it tried to serialize the 
method createObjects(). And then it tried to serialize class A. To 
serialize class A it tried to serialize the method createObjects. Or 
something like that, I do not remember the details. This caused the 
recursion.


BR,
Hilmi

Am 10.04.2016 um 19:18 schrieb Stephan Ewen:

Hi!

Is it possible that some datatype has a recursive structure nonetheless?
Something like a linked list or so, which would create a large object graph?

There seems to be a large object graph that the Kryo serializer traverses,
which causes the StackOverflowError.

Greetings,
Stephan


On Sun, Apr 10, 2016 at 6:24 PM, Andrew Palumbo <ap....@outlook.com> wrote:


Hi Stephan,

thanks for answering.

This not from a recursive object. (it is used in a recursive method in the
test that is throwing this error, but the the depth is only 2 and there are
no other Flink DataSet operations before execution is triggered so it is
trivial.)

Gere is a Gist of the code, and the full output and stack trace:

https://gist.github.com/andrewpalumbo/40c7422a5187a24cd03d7d81feb2a419

The Error begins at line 178 of the "Output" file.

Thanks

________________________________________
From: ewenstep...@gmail.com <ewenstep...@gmail.com> on behalf of Stephan
Ewen <se...@apache.org>
Sent: Sunday, April 10, 2016 9:39 AM
To: dev@flink.apache.org
Subject: Re: Kryo StackOverflowError

Hi!

Sorry, I don't fully understand he diagnosis.
You say that this stack overflow is not from a recursive/object type?

Long graphs of operations in Flink usually do not cause
StackOverflowExceptions, because not the whole graph is recursively
processed.

Can you paste the entire Stack Trace (for example to a gist)?

Greetings,
Stephan


On Sun, Apr 10, 2016 at 4:42 AM, Andrew Palumbo <ap....@outlook.com>
wrote:


Hi all,


I am working on a matrix multiplication operation for Mahout Flink
Bindings that uses quite a few chained Flink Dataset operations,


When testing, I am getting the following error:


{...}

04/09/2016 22:30:35    CHAIN Reduce (Reduce at


org.apache.mahout.flinkbindings.blas.FlinkOpABt$.abt_nograph(FlinkOpABt.scala:147))

-> FlatMap (FlatMap at


org.apache.mahout.flinkbindings.drm.BlockifiedFlinkDrm.asRowWise(FlinkDrm.scala:93))(1/1)

switched to CANCELED
04/09/2016 22:30:35    CHAIN Partition -> Map (Map at


org.apache.mahout.flinkbindings.blas.FlinkOpABt$.pairwiseApply(FlinkOpABt.scala:240))

-> GroupCombine (GroupCombine at


org.apache.mahout.flinkbindings.blas.FlinkOpABt$.abt_nograph(FlinkOpABt.scala:129))

-> Combine (Reduce at


org.apache.mahout.flinkbindings.blas.FlinkOpABt$.abt_nograph(FlinkOpABt.scala:147))(3/3)

switched to FAILED
java.lang.StackOverflowError
     at


com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:48)

     at


com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:495)

     at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:523)
     at


com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:61)

     at


com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:495)

     at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:523)
     at


com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:61)

     at


com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:495)

     at com.esotericsoftware.kryo.Kryo.writeObject(Kryo.java:523)
     at


com.esotericsoftware.kryo.serializers.ObjectField.write(ObjectField.java:61)

     at


com.esotericsoftware.kryo.serializers.FieldSerializer.write(FieldSerializer.java:495)

{...}


I've seen similar issues on the dev@flink list (and other places), but I
believe that they were from recursive calls and objects which pointed

back

to themselves somehow.


This is a relatively straightforward method, it just has several Flink
operations before execution is triggered.   If I remove some operations,
eg. a reduce, i can get the method to complete on a simple test however

the

it will then, of course be numerically incorrect.


I am wondering if there is any workaround for this type of problem?


Thank You,


Andy




--
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Hilmi Yildirim, M.Sc.
Researcher

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Intelligente Analytik für Massendaten
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Phone: +49 30 23895 1814

E-Mail: hilmi.yildi...@dfki.de

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