[jira] [Commented] (NIFI-8435) PutKudu 1.13.2 Memory Leak

["Josef Zahner (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/NIFI-8435?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17509834#comment-17509834 ] 

Josef Zahner commented on NIFI-8435:
------------------------------------

Just for reference. We have upgraded from NiFi 1.13.2 to NiFi 1.15.3 and adapted the property "Kudu Client Worker Count" to the number of "Concurrent Tasks" accordingly. So far no leaks or high memory situations anymore. However it's not ideal to have the property "Kudu Client Worker Count" as high as the number of CPUs as we have bladeservers with 64 CPUs and about 30 PutKudus in place -> leads to a lot of kudu client workers.

> 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
>             Fix For: 1.14.0
>
>         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: 1.5h
>  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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