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Posted to dev@flink.apache.org by "Andra Lungu (JIRA)" <ji...@apache.org> on 2015/06/30 10:27:04 UTC

[jira] [Created] (FLINK-2293) Division by Zero Exception

Andra Lungu created FLINK-2293:
----------------------------------

             Summary: Division by Zero Exception
                 Key: FLINK-2293
                 URL: https://issues.apache.org/jira/browse/FLINK-2293
             Project: Flink
          Issue Type: Bug
          Components: Distributed Runtime
    Affects Versions: 0.10
            Reporter: Andra Lungu


I am basically running an algorithm that simulates a Gather Sum Apply Iteration that performs Traingle Count (Why simulate it? Because you just need a superstep -> useless overhead if you use the runGatherSumApply function in Graph).
What happens, at a high level:
1). Select neighbors with ID greater than the one corresponding to the current vertex;
2). Propagate the received values to neighbors with higher ID;
3). compute the number of triangles by checking whether

trgVertex.getValue().get(srcVertex.getId());

As you can see, I *do not* perform any division at all;
code is here: https://github.com/andralungu/gelly-partitioning/blob/master/src/main/java/example/GSATriangleCount.java

Now for small graphs, 50MB max, the computation finishes nicely with the correct result. For a 10GB graph, however, I got this:

java.lang.ArithmeticException: / by zero
    at org.apache.flink.runtime.operators.hash.MutableHashTable.insertIntoTable(MutableHashTable.java:836)
    at org.apache.flink.runtime.operators.hash.MutableHashTable.buildTableFromSpilledPartition(MutableHashTable.java:819)
    at org.apache.flink.runtime.operators.hash.MutableHashTable.prepareNextPartition(MutableHashTable.java:508)
    at org.apache.flink.runtime.operators.hash.MutableHashTable.nextRecord(MutableHashTable.java:544)
    at org.apache.flink.runtime.operators.hash.NonReusingBuildFirstHashMatchIterator.callWithNextKey(NonReusingBuildFirstHashMatchIterator.java:104)
    at org.apache.flink.runtime.operators.MatchDriver.run(MatchDriver.java:173)
    at org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
    at org.apache.flink.runtime.operators.RegularPactTask.invoke(RegularPactTask.java:362)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:559)
    at java.lang.Thread.run(Thread.java:722)

see the full log here: https://gist.github.com/andralungu/984774f6348269df7951



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