[FLINK-2361] CompactingHashTable loses entries

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.10.0
• Fix Version/s: 0.9.1, 0.10.0
• Component/s: Library / Graph Processing
• Assignee: Stephan Ewen
• Reporter: Andra Lungu
• Created: 14/Jul/15 21:30
• Updated: 02/Oct/19 17:43
• Resolved: 05/Aug/15 20:16

Description

When running the simple Connected Components algorithm (currently in Gelly) on the twitter follower graph, with 1, 100 or 10000 iterations, I get the following error:

Caused by: java.lang.Exception: Target vertex '657282846' does not exist!.
at org.apache.flink.graph.spargel.VertexCentricIteration$VertexUpdateUdfSimpleVV.coGroup(VertexCentricIteration.java:300)
at org.apache.flink.runtime.operators.CoGroupWithSolutionSetSecondDriver.run(CoGroupWithSolutionSetSecondDriver.java:220)
at org.apache.flink.runtime.operators.RegularPactTask.run(RegularPactTask.java:496)
at org.apache.flink.runtime.iterative.task.AbstractIterativePactTask.run(AbstractIterativePactTask.java:139)
at org.apache.flink.runtime.iterative.task.IterationTailPactTask.run(IterationTailPactTask.java:107)
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)

Now this is very bizzare as the DataSet of vertices is produced from the DataSet of edges... Which means there cannot be a an edge with an invalid target id... The method calls flatMap to isolate the src and trg ids and distinct to ensure their uniqueness.

The algorithm works fine for smaller data sets...

Issue Links

• is duplicated by: FLINK-2443 [CompactingHashTable] GSA Connected Components fails with NPE