Complete External Task REST API calls causing high CPU usage

Camunda 7 Topics Discussion & Questions
1

Hello,

My team has a Node based app with some Camunda workers. One of these workers does what it is supposed to do, and as its last step it makes a series of sequential calls to the Complete External Task route.

Specifically, it is making 11 calls, one at a time, to complete 11 tasks. It does this quite quickly, but we noticed that CPU usage spikes during these calls, often up to 80-86% in my dev environment.

I’ve verified these calls are what is causing the spike by setting a breakpoint, letting the app pause before the calls, and then letting the calls execute. See the image below:

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image961×1029 59.6 KB

I was able to decrease CPU usage by over half by simply adding a 300ms pause between each request, but that feels like a Band-Aid that shouldn’t be necessary.

Here is how our worker is set up (we are using camunda-worker-node):

  const processSplitsWorker = new Workers(configMgr.config.camundaUri, {
    maxTasks: 1,
    pollingInterval: 100000,
    use: [
      CamundaWorkerLogger,
      CamundaWorkerMetrics
    ]
  });

And where we subscribe:

  if (camundaWorkers.includes("processSplits")) {
    processSplitsWorker.subscribe('cmeProcess:processSplits', {lockDuration: 60000}, 
 processCMESplits);
  }

And then we are making calls to /task/:taskId/complete. Everything works, but the CPU usage is high. Is there any way we can increase the performance of these calls? There seem to be a myriad of Camunda settings that can aid in performance, but I’m not sure where to start.

2

From your description it’s still not clear to me where those spikes happen. Do they happen on the client (Node) side or in the camunda engine (with the REST API)?

3

Hi @JohnKearney2020,

(additional to @fml2’s comment): Or is the CPU used by the database (you talk about the dev environment)?

Does it hurt you at all?

You can inspect the completion times in the ACT_HI_ACTINST and check if they match your expectations.

Hope this helps, Ingo

4