Thank you for that tip, Andy!
This is actually a bug I've wanted to track down and fix but it's in parts
of the NiFi codebase I'm really not familiar with and wasn't sure how to
start ... if you can connect me with someone who knows that area
(scheduling and clusters, mainly) I would be happy to see if it's something
I can patch!
On Tue, Oct 15, 2019 at 2:43 PM Andy LoPresto wrote:
> Evan,
>
> Thanks for sharing that diagnosing technique. While ideally we would have
> other controls to prevent excess CPU usage, this seems like a useful tool
> which could be automated using NiPyAPI [1] to perform a “bisect” command.
> I’ve used this for git commit searching as well as side-effect unit test
> identification.
>
> [1] https://nipyapi.readthedocs.io/en/latest/readme.html
>
>
> Andy LoPresto
> alopre...@apache.org
> *alopresto.apa...@gmail.com *
> PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4 BACE 3C6E F65B 2F7D EF69
>
> On Oct 15, 2019, at 1:40 PM, Evan Reynolds wrote:
>
> 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 be
>
> Then use the list of processors and fixes to make changes.
>
> ---
>
> Evan Reynolds
> e...@usermind.com
>
>
> *From: *Jon Logan
> *Reply-To: *"users@nifi.apache.org"
> *Date: *Sunday, October 13, 2019 at 6:12 PM
> *To: *"users@nifi.apache.org"
> *Subject: *Re: High CPU consumption
>
> That isn't logback, that lists all jars on your classpath, the first of
> which happens to be logback.
>
> 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
> wrote:
>
> 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.
>
> Thanks,
>
> LC
>
> --
> *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 wrote:
>
> 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 issues.
>
> On Sun, Oct 13, 2019 at 12:20 PM Luis Carmona
> wrote:
>
> HI,
>
> 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%.
>
