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https://issues.apache.org/jira/browse/FLINK-28034?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
ASF GitHub Bot updated FLINK-28034:
-----------------------------------
Labels: pull-request-available (was: )
> ClassCastException occurred in creating a checkpoint with merge windows
> ------------------------------------------------------------------------
>
> Key: FLINK-28034
> URL: https://issues.apache.org/jira/browse/FLINK-28034
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Checkpointing, Runtime / State Backends
> Affects Versions: 1.15.0
> Reporter: Takayuki Eimizu
> Priority: Major
> Labels: pull-request-available
>
> h1. Summary
> In Flink 1.15.0, the combination of following functions always occur
> ClassCastException.
> - Session Window
> - Checkpoint
> - Keyed State
> The following repository provides minimal source code that can combine these
> features to reproduce the exception.
> [https://github.com/t-eimizu/flink-checkpoint-with-merging-window]
>
> h1. Description
> h2. How the Exception Occurred
>
> In the process window function of the session window, we must use
> `context.globalState()`
> instead of `context.windowState()`. If you use `context.windowState()` in
> this situation, Flink throws `UnsupportedOperationException`.
>
> So we have to do following:
>
> {code:java}
> stPreviousValue = context.globalState().getState(desc4PreviousValue);
> {code}
>
> Then stPreviousValue will have the following fields:
> ||Field Name||Value||
> |currentNamespace|VoidNamespace|
> |namespaceSerializer|TimeWindow$serializer|
> As a result, when flink create checkpoint on this job, ClassCastException
> occurs.
> {code:java}
> 2022-06-14 11:04:57,212 INFO
> org.apache.flink.streaming.runtime.tasks.AsyncCheckpointRunnable [] -
> ProcessingData -> Sink: PrintData (1/1)#0 - asynchronous part of checkpoint 1
> could not be completed. java.util.concurrent.ExecutionException:
> java.lang.ClassCastException: class
> org.apache.flink.runtime.state.VoidNamespace cannot be cast to class
> org.apache.flink.streaming.api.windowing.windows.TimeWindow
> (org.apache.flink.runtime.state.VoidNamespace and
> org.apache.flink.streaming.api.windowing.windows.TimeWindow are in unnamed
> module of loader 'app') at
> java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:?] at
> java.util.concurrent.FutureTask.get(FutureTask.java:191) ~[?:?] at
> org.apache.flink.util.concurrent.FutureUtils.runIfNotDoneAndGet(FutureUtils.java:645)
> ~[flink-core-1.15.0.jar:1.15.0] at
> org.apache.flink.streaming.api.operators.OperatorSnapshotFinalizer.<init>(OperatorSnapshotFinalizer.java:54)
> ~[flink-streaming-java-1.15.0.jar:1.15.0] at
> org.apache.flink.streaming.runtime.tasks.AsyncCheckpointRunnable.finalizeNonFinishedSnapshots(AsyncCheckpointRunnable.java:191)
> ~[flink-streaming-java-1.15.0.jar:1.15.0] at
> org.apache.flink.streaming.runtime.tasks.AsyncCheckpointRunnable.run(AsyncCheckpointRunnable.java:124)
> [flink-streaming-java-1.15.0.jar:1.15.0] at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
> [?:?] at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
> [?:?] at java.lang.Thread.run(Thread.java:834) [?:?] Caused by:
> java.lang.ClassCastException: class
> org.apache.flink.runtime.state.VoidNamespace cannot be cast to class
> org.apache.flink.streaming.api.windowing.windows.TimeWindow
> (org.apache.flink.runtime.state.VoidNamespace and
> org.apache.flink.streaming.api.windowing.windows.TimeWindow are in unnamed
> module of loader 'app') at
> org.apache.flink.streaming.api.windowing.windows.TimeWindow$Serializer.serialize(TimeWindow.java:130)
> ~[flink-streaming-java-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.heap.CopyOnWriteStateMapSnapshot.writeState(CopyOnWriteStateMapSnapshot.java:145)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.heap.AbstractStateTableSnapshot.writeStateInKeyGroup(AbstractStateTableSnapshot.java:116)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.heap.CopyOnWriteStateTableSnapshot.writeStateInKeyGroup(CopyOnWriteStateTableSnapshot.java:38)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.heap.HeapSnapshotStrategy.lambda$asyncSnapshot$3(HeapSnapshotStrategy.java:172)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.SnapshotStrategyRunner$1.callInternal(SnapshotStrategyRunner.java:91)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.SnapshotStrategyRunner$1.callInternal(SnapshotStrategyRunner.java:88)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> org.apache.flink.runtime.state.AsyncSnapshotCallable.call(AsyncSnapshotCallable.java:78)
> ~[flink-runtime-1.15.0.jar:1.15.0] at
> java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?] at
> org.apache.flink.util.concurrent.FutureUtils.runIfNotDoneAndGet(FutureUtils.java:642)
> ~[flink-core-1.15.0.jar:1.15.0] ... 6 more {code}
> h2. workaround
> Turn off the checkpoint function.
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