Thomas Wozniakowski created FLINK-10960:
-------------------------------------------
Summary: 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
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:
{{
Pattern.begin(EVENT_SEQUENCE, AfterMatchSkipStrategy.skipPastLastEvent())
.times(config.getNumberOfUniqueEvents())
.where(uniquenessCheckOnAlreadyMatchedEvents())
.within(seconds(config.getWithinSeconds()));
}}
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 purchaseSequence, with
condition),
]), Start State purchaseSequence:0 [
StateTransition(TAKE, from eventSequence:0to purchaseSequence, 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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