[GIRAPH-1070] Comparators in PartitionUtils can overflow

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Assignee: Sergey Edunov
• Reporter: Sergey Edunov
• Created: 10/Jun/16 23:56
• Updated: 14/Oct/16 00:57
• Resolved: 14/Jun/16 17:56

Description

We see this exception in the logs:

ERROR 2016-06-10 16:12:20,635 [org.apache.giraph.master.MasterThread] org.apache.giraph.master.MasterThread - masterThread: Master algorithm failed with IllegalArgumentException
java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.TimSort.mergeHi(TimSort.java:899)
at java.util.TimSort.mergeAt(TimSort.java:516)
at java.util.TimSort.mergeCollapse(TimSort.java:439)
at java.util.TimSort.sort(TimSort.java:245)
at java.util.Arrays.sort(Arrays.java:1512)
at java.util.ArrayList.sort(ArrayList.java:1454)
at java.util.Collections.sort(Collections.java:175)
at org.apache.giraph.partition.PartitionUtils.analyzePartitionStats(PartitionUtils.java:159)
at org.apache.giraph.master.BspServiceMaster.assignPartitionOwners(BspServiceMaster.java:1109)
at org.apache.giraph.master.BspServiceMaster.coordinateSuperstep(BspServiceMaster.java:1581)
at org.apache.giraph.master.MasterThread.run(MasterThread.java:124)

One of the possible reasons, is overflow in comparator. Let's fix it.