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Tasks number keep increasing for NIFI processor without any input

New Contributor

I have seen that in Nifi some processors are running task without any input . I have disabled the processer and then start it again and with no input in queue, completed tasks number keep increasing. This keeps CPU busy on node without any work in progress.runningtask.jpg

I have attached the snap.

I would appreciuate if some help could be provided.


New Contributor

We are using NIFI 1.6 version

@Faheem Shoukat

What I am seeing in your screenshot looks as expected. A processor that is started and uses the Timer Driven Scheduling strategy will execute based upon the configured run schedule. The default run schedule is always 0 secs (which means execute as fast as possible). To prevent a processor that has no work to do from consuming 100% of a cpu looking for work non stop, there is a configurable yield duration (default is 1 sec). Based on your screenshot I am seeing ~293 tasks being executed every 5 minutes. This is ~1 task a second which aligns with the design explained above where a yield of 1 sec is being applied between each task.


As far as how busy this keeps a CPU, for these processors that had no work at all to do for the entire 5 minutes, your screen shots shows a cumulative CPU time for all 293 tasks of only ~0.006 seconds (this is not CPU time for each task. It is the cumulative total CPU time reported by all tasks marked as completed within that 5 minute window.)


Thank you,



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