Big difference between upstream response time and request time
mdounin at mdounin.ru
Wed Oct 15 22:03:39 MSD 2008
On Wed, Oct 15, 2008 at 10:25:20AM -0700, Praveen wrote:
> I'm using nginx as a reverse proxy to my backends. I see there is a
> huge discrepancy between upstream response time and request time.
> X.X.X.X [15/Oct/2008:09:32:57 -0700] "GET /js/something.js HTTP/1.1"
> upstream_response_time 0.005 request_time 105.026 90732578
> It's generally negligible. But sometimes its as high as 5 or more
> seconds, and in some cases as high as the example above.
> Any idea what's happening? nginx is running on a dedicated server, and
> has about 2000 active connections.
The $request_time variable measures wall clock time it took to
fully process request, from first byte got from client to last
byte sent to client. This includes time spent waiting for client
and may really vary depending on what client does / quality of
client's network connection / etc.
Generally you shouldn't pay much attention to this number unless
you have control over the client in question.
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