I am doing some performance analysis for one of our sites.
In the Nginx access_log, I record the $request_time and the
$upstream_response_time.
While looking at these logs I can see that sometimes these numbers have
a fairly large delta.
For example one request’s request_time is 1.553 while the
upstream_response_time is 0.864.
What are some of the potential causes for this large delta and is there
anything I can do about it?
A few reasons I can think of may be:
The requester is on a slow internet connection : Not much I can do
about that
Nginx is getting too many requests : Add more workers and or more
Nginx servers
While looking at these logs I can see that sometimes these numbers have a fairly
large delta.
For example one request’s request_time is 1.553 while the upstream_response_time
is 0.864.
Hello, did you find any more info on this ? I was also doing tuning on
my NGINX setup and I also wondering about this delta.
On Wed, Feb 29, 2012 at 10:38:26AM +0100, Simone F. wrote:
On 02/04/2011 07:23 AM, Zev B. wrote:
While looking at these logs I can see that sometimes these numbers have a
fairly large delta.
For example one request’s request_time is 1.553 while the
upstream_response_time is 0.864.
Hello, did you find any more info on this ? I was also doing
tuning on my NGINX setup and I also wondering about this delta.
$request_time is a total time of request processing, including
reading request from a client and sending response to the client.
$upstream_response_time is a time of obtaining response from an
upstream server.
The $request_time variable is expected to be always larger than
$upstream_response_time one as in addition to $upstream_response_time
it also includes at least a) reading request from a client and b)
sending (buffered part of) the response to the client. Both (a)
and (b) may take a while.
Maxim D.
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