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https://issues.apache.org/jira/browse/PIG-4581?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Remi Catherinot updated PIG-4581:
---------------------------------
Attachment: PIG-4581.patch
Isolate HashMap accesses by using ThreadLocal + added javadoc to state the
class is thread-safe. No unit tests because it's not possible to reproduce it
on demand.
> thread safe issue in NodeIdGenerator
> ------------------------------------
>
> Key: PIG-4581
> URL: https://issues.apache.org/jira/browse/PIG-4581
> Project: Pig
> Issue Type: Bug
> Components: impl
> Affects Versions: 0.14.0
> Environment: any computer with multiple cores, does not always happen
> since it is not a determinitic bug. The more threads and real cpu, the more
> chances it will happen.
> Reporter: Remi Catherinot
> Priority: Trivial
> Attachments: PIG-4581.patch
>
>
> NodeIdGenerator use an HashMap without any synchronization. In multithreaded
> environment it may lead to concurrent access to the HashMap which, in some
> case, triggers an infinite loop inside the HashMap implementation => the
> parsing of the pig request never ends so the job will never run + it eats a
> threads in the JVM that just keep burning CPU cycles.
> since it is hard to reproduce and it is not a deterministic bug it is
> impossible to provide a viable unit tests for it to demonstrate both the bug
> and the fix.
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