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https://issues.apache.org/jira/browse/FLINK-16069?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17354757#comment-17354757
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Zhu Zhu commented on FLINK-16069:
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Even if the main thread can have the highest priority, GC problem can still
happen when serialized {{TaskDeploymentDescriptor}}s are generated too fast and
queued to be sent out. These queued {{TaskDeploymentDescriptor}}s will cost
lots of memory and cannot be {{GC}}ed before sent out. Frequent young GC would
consume lots of CPU. And more heap memory will be required or consecutive full
GC could happen.
> Creation of TaskDeploymentDescriptor can block main thread for long time
> ------------------------------------------------------------------------
>
> Key: FLINK-16069
> URL: https://issues.apache.org/jira/browse/FLINK-16069
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Coordination
> Reporter: huweihua
> Priority: Major
> Attachments: FLINK-16069-POC-results
>
>
> The deploy of tasks will take long time when we submit a high parallelism
> job. And Execution#deploy run in mainThread, so it will block JobMaster
> process other akka messages, such as Heartbeat. The creation of
> TaskDeploymentDescriptor take most of time. We can put the creation in future.
> For example, A job [source(8000)->sink(8000)], the total 16000 tasks from
> SCHEDULED to DEPLOYING took more than 1mins. This caused the heartbeat of
> TaskManager timeout and job never success.
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