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Re: [Bug 62318] healthcheck


On Fri, Aug 24, 2018 at 1:05 PM Jim Jagielski <jim@xxxxxxxxxxx> wrote:
>
>
>
> On Aug 24, 2018, at 12:05 PM, Eric Covener <covener@xxxxxxxxx> wrote:
>
> On Fri, Aug 24, 2018 at 11:57 AM Christophe JAILLET
> <christophe.jaillet@xxxxxxxxxx> wrote:
>
>
> Le 24/08/2018 à 16:40, Jim Jagielski a écrit :
>
> I was wondering if someone wanted to provide a sanity check
> on the above PR and what's "expected" by the health check code.
>
> It would be very easy to adjust so that hcinterval was not
> the time between successive checks but the interval between
> the end of one and the start of another, but I'm not sure that
> is as useful. In other words, I think the current behavior
> is right (but think the docs need to be updated), but am
> willing to have my mind changed :)
>
> Hi Jim,
>
> the current behavior is also what I would expect.
> If I configure a check every 10s, I would expect 6 checks each minute,
> even if the test itself takes time to perform.
>
>
>
> Bug describes something else IIUC.  Because the watchdog calls us 10
> times per second, it continuously sees that the worker hasn't been
> health checked within the desired interval and queues up a check, it
> doesn't know one is queued.
>
>
> But that is only an issue, afaict, if the time taken to do the health check is
> greater than the interval chosen... Or am I misunderstanding? That is,
> if the interval is 200ms, and the health check takes 100ms, all is fine, we
> get 5 checks a second.

I don't think it's hc execution time relatve to interval, it's hc
execution time relative to AP_WD_TM_SLICE.  If it's much more than
AP_WD_TM_SLICE they'll stack up while one is running.
For a 1 second response you could queue up 10 in a second even if you
only have an interval of as minute or hour.