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From Evan Reynolds <>
Subject Re: High CPU consumption
Date Tue, 15 Oct 2019 20:40:07 GMT
I have found two issues that can cause high CPU when idle (high being about 200% CPU when idle.)
I haven’t verified these with 1.9.2, but it doesn’t hurt to tell you.

If you are using ports, make sure each input port is connected. If you have a one that isn’t
connected, that can bring your CPU to 200% and stay there.

If you have any processors that are set to run on the primary node of a cluster, that can
also take your CPU to 200%. I know RouteOnAttribute will do that (again, haven’t tested
1.9.2, but it was a problem for me for a bit!) The fix – either don’t run it on the primary
node, or else set the run schedule to 5 seconds or something instead of 0.

To find out if this is the case – well, this is what I did. It worked, and wasn’t that
hard, though isn’t exactly elegant.

Back up your flowfile (flow.xml.gz)
Stop all your processors and see what your CPU does
Start half of them and watch your CPU – basically do a binary search. If your CPU stays
reasonable, then whatever group you started is fine. If not, then start stopping things until
your CPU becomes reasonable.
Eventually you’ll find a processor that spikes your CPU when you start it and then you can
figure out what to do about that processor. Record which processor it is and how you altered
it to bring CPU down.
Repeat, as there may be more than one processor spiking CPU.
Stop NiFi and restore your flowfile by copying it back in place – since you were running
around stopping things, this just makes sure everything is correctly back to where it should

Then use the list of processors and fixes to make changes.


Evan Reynolds<>

From: Jon Logan <>
Reply-To: "" <>
Date: Sunday, October 13, 2019 at 6:12 PM
To: "" <>
Subject: Re: High CPU consumption

That isn't logback, that lists all jars on your classpath, the first of which happens to be

If you send a SIGKILL3 (you can send it in HTOP) it will dump the thread stacks to stdout
(probably the bootstrap log)...but that's just for one instant, and may or may not be helpful.

On Sun, Oct 13, 2019 at 8:58 PM Luis Carmona <<>>
hi Aldrin,

thanks a  lot, by now I'm trying to learn how to make the profiling you mentioned.

One more question: Is it normal that the father java process has very low consumption while
the child process related to logback jar is the one that is eating up all the CPU ?
Please take a look at the attached image.



From: "Aldrin Piri" <<>>
To: "users" <<>>
Sent: Sunday, October 13, 2019 9:30:47 PM
Subject: Re: High CPU consumption

Luis, please feel free to give us some information on your flow so we can help you track down
problematic areas as well.

On Sun, Oct 13, 2019 at 3:56 PM Jon Logan <<>>
You should put a profiler on it to be sure.
Just because your processors aren't processing data doesn't mean they are idle though -- many
have to poll for new data, especially sources -- ex. connecting to Kafka, etc, will itself
consume some CPU.

But again, you should attach a profiler before participating in a wild goose chase of performance

On Sun, Oct 13, 2019 at 12:20 PM Luis Carmona <<>>

I've struggling to reduce my nifi installation CPU consumption. Even in idle state, all processors
running but no data flowing, it is beyond 60% CPU consumption, with peaks of 200%.

What I've done so far
- Read and followed every instruction/post about tuning NIFI I've found googling.
- Verify scheduling is 1s for most consuming processors: http processors, wait/notify, jolt,
- Scratch my head...

But nothing seems to have a major effect on the issue.

Can anyone give me some precise directions or tips about how to solve this please ?
Is this the regular situation, I mean this is the minimun NIFI consumption.

The server is configure with 4 CPU's, 8 GB RAM - 4 of them dedicated to heap at bootstrap.conf.

Thanks in advance.


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