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https://issues.apache.org/jira/browse/FLINK-18353?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17139094#comment-17139094
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Xintong Song commented on FLINK-18353:
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+1 from my side.
I think we did mentioned
[here|https://ci.apache.org/projects/flink/flink-docs-master/ops/memory/mem_setup.html#jvm-parameters]
that we are setting `-XX:MaxDirectMemorySize` for both JM/TM processes. This
breaking change should also be included in the 1.11.0 release notes (per
[FLINK-16614|https://issues.apache.org/jira/browse/FLINK-16614?focusedCommentId=17117630&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-17117630]).
But I think it still make sense to explicitly mention this in the migration
guide. WDTY? [~azagrebin]
> [1.11.0] maybe document jobmanager behavior change regarding
> -XX:MaxDirectMemorySize
> ------------------------------------------------------------------------------------
>
> Key: FLINK-18353
> URL: https://issues.apache.org/jira/browse/FLINK-18353
> Project: Flink
> Issue Type: Improvement
> Components: Documentation, Runtime / Configuration
> Affects Versions: 1.11.0
> Reporter: Steven Zhen Wu
> Priority: Major
>
> I know FLIP-116 (Unified Memory Configuration for Job Managers) is introduced
> in 1.11. That does cause a small behavior change regarding
> `-XX:MaxDirectMemorySize`. Previously, jobmanager don't set JVM arg
> `-XX:MaxDirectMemorySize`, which means JVM can use up to -`Xmx` size for
> direct memory. Now `-XX:MaxDirectMemorySize` is always set to
> [jobmanager.memory.off-heap.size|https://ci.apache.org/projects/flink/flink-docs-master/ops/config.html#jobmanager-memory-off-heap-size]
> config (default 128 mb).
>
> {{It is possible for jobmanager to get "java.lang.OufOfMemoryError: Direct
> Buffer Memory" without tuning
> }}{{[jobmanager.memory.off-heap.size|https://ci.apache.org/projects/flink/flink-docs-master/ops/config.html#jobmanager-memory-off-heap-size]}}
> especially for high-parallelism jobs. Previously, no tuning needed.
>
> Maybe we should point out the behavior change in the migration guide?
> [https://ci.apache.org/projects/flink/flink-docs-master/ops/memory/mem_migration.html#migrate-job-manager-memory-configuration]
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