[FLINK-18332] Add error message to precondition in KeyGroupPartitionedPriorityQueue

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.10.0, 1.10.1
• Fix Version/s: 1.12.0
• Component/s: Runtime / Queryable State
• Labels: pull-request-available

Environment

CentOS 7.0

Flink 1.10.0

jdk-1.8

• Assignee: tartarus
• Reporter: tartarus
• Created: 16/Jun/20 13:30
• Updated: 17/Jun/20 03:29
• Resolved: 17/Jun/20 03:29

Description

in my case, the user custom a KeySelector and use a static SimpleDateFormat to format unix timestamp. sometimes job will throw an ArrayIndexOutOfBoundsException

java.lang.ArrayIndexOutOfBoundsException: -49
	at org.apache.flink.runtime.state.heap.KeyGroupPartitionedPriorityQueue.getKeyGroupSubHeapForElement(KeyGroupPartitionedPriorityQueue.java:174)
	at org.apache.flink.runtime.state.heap.KeyGroupPartitionedPriorityQueue.add(KeyGroupPartitionedPriorityQueue.java:110)
	at org.apache.flink.streaming.api.operators.InternalTimerServiceImpl.registerProcessingTimeTimer(InternalTimerServiceImpl.java:203)
	at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator$Context.registerProcessingTimeTimer(WindowOperator.java:901)
	at org.apache.flink.streaming.api.windowing.triggers.ProcessingTimeTrigger.onElement(ProcessingTimeTrigger.java:36)
	at org.apache.flink.streaming.api.windowing.triggers.ProcessingTimeTrigger.onElement(ProcessingTimeTrigger.java:28)
	at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator$Context.onElement(WindowOperator.java:920)
	at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:402)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.processRecord(OneInputStreamTask.java:204)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.emitRecord(OneInputStreamTask.java:196)
	at org.apache.flink.streaming.runtime.io.StreamTaskNetworkInput.processElement(StreamTaskNetworkInput.java:151)
	at org.apache.flink.streaming.runtime.io.StreamTaskNetworkInput.emitNext(StreamTaskNetworkInput.java:128)
	at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:69)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:311)
	at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:187)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:487)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:470)
	at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:707)
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:532)
	at java.lang.Thread.run(Thread.java:745)

I reproduced this case.
Because keySelector.getKey() will be called twice on the same record, and SimpleDateFormat is not thread safe, In the case of high concurrency and Cross Days, the results returned by the two calls of keySelector.getKey() may be different.
So the keygroup calculated in the second execution is different from the result of the first calculation，then throw an ArrayIndexOutOfBoundsException.

I think the error message should be clearer, not just the ArrayIndexOutOfBoundsException.

Issue Links

• links to: GitHub Pull Request #12508