Big difference between upstream response time and request time

Praveen praveen.krishnamurthy at
Thu Oct 16 00:26:26 MSD 2008

Thanks! What about the upstream response time? I'm assuming that it is
time from initiating a connection to the backend server till the last
byte of the response is received.


On Wed, Oct 15, 2008 at 11:03 AM, Maxim Dounin <mdounin at> wrote:
> Hello!
> On Wed, Oct 15, 2008 at 10:25:20AM -0700, Praveen wrote:
>> Hi,
>> 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.
> Maxim Dounin


Can you yell "Movie!" in a crowded firestation?

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