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https://issues.apache.org/jira/browse/FLINK-32746?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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xiangyu feng closed FLINK-32746.
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Resolution: Done
JDK17 is already supported in
https://issues.apache.org/jira/browse/FLINK-15736, user can enable ZGC by
configuring by customizing the `env.java.opts.all` parameter. There already
have a example in OLAP QuickStart
docs：https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/olap_quickstart/
> Using ZGC in JDK17 to solve long time class unloading STW
> ---------------------------------------------------------
>
> Key: FLINK-32746
> URL: https://issues.apache.org/jira/browse/FLINK-32746
> Project: Flink
> Issue Type: Sub-task
> Components: Table SQL / Runtime
> Reporter: xiangyu feng
> Priority: Major
>
> In a OLAP session cluster, a TM need to frequently create new classloaders
> and generate new classes. These classes will be accumulated in metaspace.
> When metaspace data usage reaches a threshold, a FullGC with a long time
> Stop-the-World will be triggered. Currently, both SerialGC, ParallelGC and
> G1GC are doing Stop-the-World class unloading. Only ZGC supports concurrent
> class unload, see more in
> [https://bugs.openjdk.org/browse/JDK-8218905|https://bugs.openjdk.org/browse/JDK-8218905).].
>
> In our scenario, a class unloading for a 2GB metaspace with 5million classes
> will stop the application more than 40 seconds. After switch to ZGC, the
> maximum STW of the application has been reduced to less than 10ms.
>
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