Sporadic long response times with upstream server

Peter Booth peter_booth at me.com
Thu Feb 21 08:51:35 UTC 2019


You need to find out what is “true”. From the perspective of nginx, 
this post request took 3.02 secs - but where was the time actually spent?
Do you have root access on both your nginx host and your upstream host
that is behind your elastic load balancer? If so, you can run a filtered tcpdump 
on both to see what is occurring at the tcp level as you drive traffic through your
web application. Then try to find out

“whats different about the 3 second scenario and the < 100ms scenario?”
“are there any persistent connections?”
Is it this issue?
https://labs.ripe.net/Members/gih/the-curious-case-of-the-crooked-tcp-handshake <https://labs.ripe.net/Members/gih/the-curious-case-of-the-crooked-tcp-handshake>
You can adjust the net.inet.tcp.finwait2_timeout
 and similar and see if that changes the length of your three second effect to something else.

Hope this helps,



> On 21 Feb 2019, at 11:51 AM, joncard <nginx-forum at forum.nginx.org> wrote:
> That's meant to read, "I think this indicates a delay in Nginx," which was
> the whole point. Sorry.
> Posted at Nginx Forum: https://forum.nginx.org/read.php?2,283099,283101#msg-283101
> _______________________________________________
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