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https://issues.apache.org/jira/browse/BEAM-14187?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Luke Cwik reopened BEAM-14187:
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> NullPointerException or IllegalStateException at IsmReaderImpl in Dataflow
> --------------------------------------------------------------------------
>
> Key: BEAM-14187
> URL: https://issues.apache.org/jira/browse/BEAM-14187
> Project: Beam
> Issue Type: Bug
> Components: runner-dataflow
> Reporter: Minbo Bae
> Assignee: Minbo Bae
> Priority: P2
> Fix For: 2.39.0
>
> Time Spent: 2h 50m
> Remaining Estimate: 0h
>
> h6. Problem
> Dataflow Java batch jobs with large side input intermittently throws
> {{NullPointerException}} or {{{}IllegalStateException{}}}.
> *
> [NullPointerException|https://gist.githubusercontent.com/baeminbo/459e283eadbc7752c9f23616b52d958a/raw/f0480b8eaff590fb3f3ae2ab98ddce7dd3b4a237/npe.png]
> happens at
> [IsmReaderImpl.overKeyComponents|https://github.com/apache/beam/blob/v2.37.0/runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/IsmReaderImpl.java#L217]:
> *
> [IllegalStateException|https://gist.githubusercontent.com/baeminbo/459e283eadbc7752c9f23616b52d958a/raw/f0480b8eaff590fb3f3ae2ab98ddce7dd3b4a237/IllegalStateException.png]
> happens at [IsmReaderImpl. initializeForKeyedRead
> |https://github.com/apache/beam/blob/v2.37.0/runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/IsmReaderImpl.java#L500].
> (all error logs in the Dataflow job is
> [here|https://gist.githubusercontent.com/baeminbo/459e283eadbc7752c9f23616b52d958a/raw/f0480b8eaff590fb3f3ae2ab98ddce7dd3b4a237/downloaded-logs-20220327-171955.json].)
> h6. Hypothesis
> The {{initializeForKeyedRead}} is not synchronized. Multiple threads can
> enter the method so that initialize the index for the same shard and update
> {{indexPerShard}} without synchronization. And, the {{overKeyComponents}}
> also accesses {{indexPerShard}} without synchronization. As {{indexPerShard}}
> is just a {{HashMap}} which is not thread-safe, it can cause
> {{NullPointerException}} and {{IllegalStateException}} above.
> h6. Suggestion
> I think it can fix this issue if we change the type of {{indexPerShard}} to a
> thread-safe map (e.g. {{ConcurrentHashMap}}).
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