cpugputpu created FLINK-16235:
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Summary: Use LinkedHashSet in StreamGraph.java
Key: FLINK-16235
URL: https://issues.apache.org/jira/browse/FLINK-16235
Project: Flink
Issue Type: Bug
Reporter: cpugputpu
The test in
_org.apache.flink.streaming.api.graph.StreamingJobGraphGeneratorTest#testSlotSharingOnAllVerticesInSameSlotSharingGroupByDefaultDisabled_
will cause the following failure:
java.lang.AssertionError: expected:<SlotSharingGroup
feca28aff5a3958840bee985ee7de4d3> but was:<SlotSharingGroup
798f7268aeb5fde00858b7c9723d65f1>
at
org.apache.flink.streaming.api.graph.StreamingJobGraphGeneratorTest.assertSameSlotSharingGroup(StreamingJobGraphGeneratorTest.java:843)
at
org.apache.flink.streaming.api.graph.StreamingJobGraphGeneratorTest.testSlotSharingOnAllVerticesInSameSlotSharingGroupByDefaultDisabled(StreamingJobGraphGeneratorTest.java:814)
I analyze the assertion failure and find that the root cause of it lies in the
clear() method in StreamGraph.java, where the variable _sources_ is initialized
as a HashSet. Because the iteration order of HashSet is non-deterministic, so
the test becomes flaky.
The fix is to change _HashSet_ to _LinkedHashSet_ and then the failure above is
removed.
The stacktrace information is presented as follows for your reference:
java.util.HashSet.iterator(HashSet.java:173)
org.apache.flink.streaming.api.graph.StreamingJobGraphGenerator.setChaining(StreamingJobGraphGenerator.java:251)
org.apache.flink.streaming.api.graph.StreamingJobGraphGenerator.createJobGraph(StreamingJobGraphGenerator.java:166)
org.apache.flink.streaming.api.graph.StreamingJobGraphGenerator.createJobGraph(StreamingJobGraphGenerator.java:104)
org.apache.flink.streaming.api.graph.StreamingJobGraphGenerator.createJobGraph(StreamingJobGraphGenerator.java:100)
org.apache.flink.streaming.api.graph.StreamingJobGraphGeneratorTest.testSlotSharingOnAllVerticesInSameSlotSharingGroupByDefaultDisabled(StreamingJobGraphGeneratorTest.java:803)
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