[FLINK-4878] ReduceTaskExternalITCase.testMultiLevelMergeCombiningReduceTask test instable

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Cannot Reproduce
• Affects Version/s: 1.2.0
• Component/s: Runtime / Task
• Labels: test-stability
• Assignee: Unassigned
• Reporter: Robert Metzger
• Created: 21/Oct/16 09:16
• Updated: 06/Mar/18 10:48
• Resolved: 06/Mar/18 10:48

Description

The ReduceTaskExternalITCase.testMultiLevelMergeCombiningReduceTask test failed with the following error

testMultiLevelMergeCombiningReduceTask[0](org.apache.flink.runtime.operators.ReduceTaskExternalITCase)  Time elapsed: 0.233 sec  <<< FAILURE!
java.lang.AssertionError: Invoke method caused exception.
	at org.junit.Assert.fail(Assert.java:88)
	at org.apache.flink.runtime.operators.ReduceTaskExternalITCase.testMultiLevelMergeCombiningReduceTask(ReduceTaskExternalITCase.java:193)

Here is the log https://s3.amazonaws.com/archive.travis-ci.org/jobs/169181202/log.txt

Sadly, the test is not logging the exception at INFO level, so we can not really understand what's going on.

I'll push a commit improving the logging.