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https://issues.apache.org/jira/browse/FLINK-10960?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Thomas Wozniakowski closed FLINK-10960.
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Resolution: Workaround
Release Note: It seems this issue was as David described, due to restoring
into a smaller state machine than had existed before
> CEP: Job Failure when .times(2) is used
> ---------------------------------------
>
> Key: FLINK-10960
> URL: https://issues.apache.org/jira/browse/FLINK-10960
> Project: Flink
> Issue Type: Bug
> Components: CEP
> Affects Versions: 1.6.2
> Reporter: Thomas Wozniakowski
> Priority: Critical
>
> Hi Guys,
> Encountered a strange one today. We use the CEP library in a configurable way
> where we plug a config file into the Flink Job JAR and it programmatically
> sets up a bunch of CEP operators matching the config file.
> I encountered a strange bug when I was testing with some artificially low
> numbers in our testing environment today. The CEP code we're using (modified
> slightly) is:
> {code:java}
> Pattern.begin(EVENT_SEQUENCE, AfterMatchSkipStrategy.skipPastLastEvent())
> .times(config.getNumberOfUniqueEvents())
> .where(uniquenessCheckOnAlreadyMatchedEvents())
> .within(seconds(config.getWithinSeconds()));
> {code}
> When using the {{numberOfUniqueEvents: 2}}, I started seeing the following
> error killing the job whenever a match was detected:
> {quote}
> ava.lang.RuntimeException: Exception occurred while processing valve output
> watermark:
> at
> org.apache.flink.streaming.runtime.io.StreamInputProcessor$ForwardingValveOutputHandler.handleWatermark(StreamInputProcessor.java:265)
> at
> org.apache.flink.streaming.runtime.streamstatus.StatusWatermarkValve.findAndOutputNewMinWatermarkAcrossAlignedChannels(StatusWatermarkValve.java:189)
> at
> org.apache.flink.streaming.runtime.streamstatus.StatusWatermarkValve.inputWatermark(StatusWatermarkValve.java:111)
> at
> org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:184)
> at
> org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:105)
> at
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:300)
> at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: org.apache.flink.util.FlinkRuntimeException: State eventSequence:2
> does not exist in the NFA. NFA has states [Final State $endState$ [
> ]), Normal State eventSequence [
> StateTransition(TAKE, from eventSequenceto $endState$, with condition),
> StateTransition(IGNORE, from eventSequenceto eventSequence, with
> condition),
> ]), Start State eventSequence:0 [
> StateTransition(TAKE, from eventSequence:0to eventSequence, with
> condition),
> ])]
> at org.apache.flink.cep.nfa.NFA.isStartState(NFA.java:144)
> at org.apache.flink.cep.nfa.NFA.isStateTimedOut(NFA.java:270)
> at org.apache.flink.cep.nfa.NFA.advanceTime(NFA.java:244)
> at
> org.apache.flink.cep.operator.AbstractKeyedCEPPatternOperator.advanceTime(AbstractKeyedCEPPatternOperator.java:389)
> at
> org.apache.flink.cep.operator.AbstractKeyedCEPPatternOperator.onEventTime(AbstractKeyedCEPPatternOperator.java:293)
> at
> org.apache.flink.streaming.api.operators.InternalTimerServiceImpl.advanceWatermark(InternalTimerServiceImpl.java:251)
> at
> org.apache.flink.streaming.api.operators.InternalTimeServiceManager.advanceWatermark(InternalTimeServiceManager.java:128)
> at
> org.apache.flink.streaming.api.operators.AbstractStreamOperator.processWatermark(AbstractStreamOperator.java:746)
> at
> org.apache.flink.streaming.runtime.io.StreamInputProcessor$ForwardingValveOutputHandler.handleWatermark(StreamInputProcessor.java:262)
> {quote}
> Changing the config to {{numberOfUniqueEvents: 3}} fixed the problem.
> Changing it back to 2 brought the problem back. It seems to be specifically
> related to the value of 2.
> This is not a blocking issue for me because we typically use much higher
> numbers than this in production anyway, but I figured you guys might want to
> know about this issue.
> Let me know if you need any more information.
> Tom
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