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https://issues.apache.org/jira/browse/FLINK-32137?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17725160#comment-17725160
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Rui Fan commented on FLINK-32137:
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Hi [~netvl] , thanks for your report.
It is an ease-of-use improvement for flame graph usage. After my analysis, the
`MailboxDefaultAction to StreamTask.processInput` is also a lambda, it needs to
be optimized as well. Would you like to make these improvements?
By the way, FLINK-30583 (Flink 1.17) supports viewing the flamegraph at the
subtask level, it should be useful for troubleshooting. You can just view the
subtask with high busy ratio.
!image-2023-05-23-11-01-30-391.png!
> Flame graph is hard to use with many task managers
> --------------------------------------------------
>
> Key: FLINK-32137
> URL: https://issues.apache.org/jira/browse/FLINK-32137
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Web Frontend
> Affects Versions: 1.16.1
> Reporter: Vladimir Matveev
> Priority: Major
> Attachments: image (1).png, image-2023-05-23-11-01-30-391.png
>
>
> In case there are many task managers executing the same operator, the flame
> graph becomes very hard to use. As you can see on the attached picture, it
> considers instances of the same lambda function as different classes, and
> their number seems to be equal to the number of task managers (i.e. each JVM
> gets its own "class" name, which is expected for lambdas I guess). This
> lambda function is deep within Flink's own call stack, so this kind of graph
> is inevitable regardless of the job's own logic, and there is nothing we can
> do at the job logic's level to fix it.
> This behavior makes evaluating the flame graph very hard, because all of the
> useful information gets "compressed" inside each "column" of the graph, and
> at the same time, it does not give any useful information since this is just
> an artifact of the class name generation in the JVM.
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