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https://issues.apache.org/jira/browse/NIFI-8435?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17326985#comment-17326985
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David Handermann commented on NIFI-8435:
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[~jzahner] I put together PR 5020 to add a {{Kudu Client Worker Count}}
property for {{PutKudu}}. The default value uses the same approach as
{{KuduClient}}, but for your use case, it seems like a smaller number, matching
the number of Concurrent Tasks configured for PutKudu, would be better. The PR
also ensures that {{KuduSession}} is always closed. The custom worker count
number also provided the opportunity to set a custom ThreadFactory so that
thread names now include the Processor Identifier, which should be helpful for
troubleshooting. Kudu changes from Netty 3 to Netty 4 have definitely impacted
the memory footprint, so I do not expect these changes to be a complete
resolution. However, if you have any feedback on the PR, feel free to add
comments.
> PutKudu 1.13.2 Memory Leak
> --------------------------
>
> Key: NIFI-8435
> URL: https://issues.apache.org/jira/browse/NIFI-8435
> Project: Apache NiFi
> Issue Type: Bug
> Components: Extensions
> Affects Versions: 1.13.2
> Environment: NiFi 1.13.2, 8-Node Cluster running on CentOS 7, Kudu
> 1.10.0
> Reporter: Josef Zahner
> Assignee: Peter Gyori
> Priority: Critical
> Labels: kudu, nifi, oom
> Attachments: Screenshot 2021-04-20 at 14.27.11.png,
> grafana_heap_overview.png, kudu_inserts_per_sec.png,
> putkudu_processor_config.png, visualvm_bytes_detail_view.png,
> visualvm_total_bytes_used.png
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> We just upgraded from NiFi 1.11.4 to 1.13.2 and faced a huge issue with
> PutKudu.
> PutKudu on the 1.13.2 eats up all the heap memory and garbage collection
> can't anymore free up the memory. We allow Java to use 31GB memory and as you
> can see with NiFi 1.11.4 it will be used like it should with GC. However with
> NiFi 1.13.2 with our actual load it fills up the memory relatively fast.
> Manual GC via visualvm tool didn't help at all to free up memory.
> !grafana_heap_overview.png!
>
> Visual VM shows the following culprit: !visualvm_total_bytes_used.png!
> !visualvm_bytes_detail_view.png!
> The bytes array shows millions of char data which isn't cleaned up. In fact
> here 14,9GB memory (heapdump has been taken after a while of full load). If
> we check the same on NiFi 1.11.4, the bytes array is nearly empty, around a
> few hundred MBs.
> As you could imagine we can't upload the heap dump as currently we have only
> productive data on the system. But don't hesitate to ask questions about the
> heapdump if you need more information.
> I haven't done any screenshot of the processor config, but I can do that if
> you wish (we are back to NiFi 1.11.4 at the moment).
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