[FLINK-2293] Division by Zero Exception

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.9, 0.10.0
• Fix Version/s: 0.9.1, 0.10.0
• Component/s: Runtime / Task
• Assignee: Stephan Ewen
• Reporter: Andra Lungu
• Created: 30/Jun/15 08:26
• Updated: 02/Oct/19 17:45
• Resolved: 10/Jul/15 08:34

Description

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