[Pdns-users] CPU Usage Regression in Recursor 4.9.1?

[Otto Moerbeek]

On Mon, Sep 04, 2023 at 10:30:38AM +0200, Christoph via Pdns-users wrote:

> 
> > Thanks, recursor is now running with aggressive-nsec-cache-size=0
> > and I'll report my findings after a few days.
> 
> Already after less than a day I can say that this setting mitigates
> the problem, thank you very much!
> The CPU usage is significantly lower and stopped growing after 12 hours at a
> lower level than without the setting. Also the drop rate is back to an usual
> level.
> 
> 'Timeout while waiting for the health check response from backend'
> event counts also got reduced drastically:
> 
>    4529 2023-09-03
>      65 2023-09-04 (10hours only)
> 
> 
> Is this related to this 4.9.1 changelog entry?
> > Replace data in the aggressive cache if new data becomes available.
> > 
> > References: #13106, pull request 13161

Yes, that is very likely. I do not understand the issue completely
yet, in my testing the changes do not cause any significant change in
CPU time. But I'm on it.

	-Otto

> 
> best regards,
> Christoph
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