Reg: exact field for response time

[Hardik]

Thanks Geoff.

It cleared my doubt. Means Both fields in 3 and 6 are same ( Agree with you
that its not always).

"At the risk of repeating the answer that you didn't like, timestamps in
Varnish 6 give you three values"
*This line made my day...*

One question now ..
what time should give to customer as a response time? Is it 2nd field(Total
round trip time) or 3rd field(only response time after processed fetched
content) ?
       Timestamp Resp: 1501601912.806787* 0.048125* *0.000037*

Reason of asking this question is, Only first time request will go to
origin. After that next all the request will be served from cache. Also
generally we do not have control over other network (customer's network)
when request goes to origin. As per this understanding, I should give 3rd
field to customer as per response time. Please correct me if I am wrong.

Thanks again Geoff.

-Hardik


On Tue, 19 Mar 2019 at 18:06, Geoff Simmons <geoff at uplex.de> wrote:

> On 3/19/19 11:00, Hardik wrote:
> >
> > Please help with understanding.
>
> Well I tried with my previous answer, but you didn't seem to be
> satisfied with that. I'm not sure what else I can say.
>
> >> This line is creating confusion for me..
> >>
> >> https://github.com/jib/libvmod-timers/blob/master/src/vmod_timers.c
> >> The sixth and last number (0.000025988) is the time from we start
> >> delivering the object until the request completes.
>
> That appears to be exactly the same as what we had in the old wiki,
> which as I recall was the only documentation we ever had for ReqEnd in
> Varnish 3:
>
> https://varnish-cache.org/trac/wiki/Varnishlog
>
> The statement about the sixth and last number has a bit of a grammatical
> error, but what it's saying is that it's the duration of delivery -- the
> time needed to send the client response.
>
> >>> I am not getting difference between varnish 3 and varnish 6.
>
> That's where you're losing me, and I suspect the problem is that you're
> looking for something Varnish 6 that corresponds exactly to what you
> were reading in Varnish 3.
>
> Generally speaking, they don't correspond. At the risk of repeating the
> answer that you didn't like, timestamps in Varnish 6 give you three values:
>
> * an absolute time (Unix epoch)
> * time elapsed since the beginning of request processing
> * time elapsed since the last timestamp
>
> However displeasing it may be, that's the way it is.
>
> In *practical* terms, you probably *are* getting a corresponding value
> in the third field of Timestamp:Resp, because of the fact that it
> follows Timestamp:Process.
>
> Again repeating the reference to
> https://varnish-cache.org/docs/trunk/reference/vsl.html#timestamps:
>
> Process
>     Processing finished, ready to deliver the client response.
> Resp
>     Delivery of response to the client finished.
>
> Since Timestamp:Resp follows Timestamp:Process, and the third field is
> the difference since the last timestamp, then the third field of
> Timestamp:Resp is the difference between "ready to deliver the client
> response" and "Delivery of response to the client finished". In other
> words, the duration of delivery.
>
> So if you're insisting on asking "is that field in Varnish 6 the same as
> the field in Varnish 3", then fine, they're essentially the same thing.
>
> The reason I'm reluctant to just say yes is that it's possible (although
> very uncommon) for some *other* timestamp to appear before
> Timestamp:Resp in the log. If that does happen (a rare case, if at all),
> then they're not the same.
>
> Hardik, I believe you'll be much better off if you come to terms with
> the fact that the timestamps in Varnish 3 and Varnish 6 just aren't the
> same. You're using Varnish 6 now, so go with the way it works.
>
>
> Trying my best,
> Geoff
> --
> ** * * UPLEX - Nils Goroll Systemoptimierung
>
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>
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>
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>
>
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