Bad times in client but not backend side for not cached request

[Rodrigo García Suárez]

Hello everybody.

I have this weird issue with Varnish 5.0.0 on Debian 9.4 and maybe somebody
here can help me with it.

The thing is, I have this request:

https://somehost.com//cart/current_cart.json?clear_cart=false&_=1550491039254

It is always a miss in varnish (as it should be) and making only one, works
just fine.

But doing some performance testing the response times increases quickly.
For example, with 2 requests/s, after 4 or 5 request, the response time
begins to increase exponentially and after 20 request I have 11s of
latency, reaching 40s after 40 requests.

If I take out Varnish (sending the request from nginx to the app) it works
just fine. And looking at the varnish log, the "%T" format option in the
backend log keeps a response <=1s but in the client side I see the
incremental reponse times.

The request can't be cached so now I am keeping it out from varnish but I
don't like the idea of this exception in the configuration and I am worry
it could reproduce with other requests (in fact I have two other suspects)
so any idea or suggestion will be greatly appreciated.

Thanks for your time.


-- 
Rodrigo García Suárez
rodrigo.garcia at the-cocktail.com
679 141 132

The Cocktail
c/ Salamanca 17
28020 Madrid
(+34) 915 670 605

www > http://the-cocktail.com

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