[NIFI-8435] PutKudu 1.13.2 Memory Leak

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.13.2
• Fix Version/s: 1.14.0
• Component/s: Extensions
• Labels: kudu nifi oom
• Environment: NiFi 1.13.2, 8-Node Cluster running on CentOS 7, Kudu 1.10.0
• Assignee: Peter Gyori
• Reporter: Josef Zahner
• Created: 15/Apr/21 13:29
• Updated: 21/Mar/22 13:50
• Resolved: 19/May/21 19:36

Description

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.

 

Visual VM shows the following culprit:

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). 

Issue Links

• fixes: NIFI-7970 PutKudu does not close Kudu Session if unable to communicate with Kudu
• relates to: NIFI-9767 PutKudu OutOfMemory Exception (GC overhead limit exceeded)
• relates to: NIFI-9820 Change PutKudu Property "Kudu Client Worker Count" Default Value
• links to: GitHub Pull Request #5020
• links to: Netty Issue 9768