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From Eric Covener <cove...@gmail.com>
Subject Re: [users@httpd] What is %D in access log meassuring?
Date Thu, 31 Mar 2011 13:09:27 GMT
On Thu, Mar 31, 2011 at 8:37 AM, Janne H <jannehson51@yahoo.com> wrote:
> --- On Thu, 3/31/11, Mark Montague <mark@catseye.org> wrote:
>
>> > In the access log, what is acctually meassured with
>> the %D option?
>> >
>> > %D The time taken to serve the request, in
>> microseconds.
>> >
>> > but what is included in this time? Is the stopwatch
>> started when the last byte of the request is received and
>> stoped when the first  byte of the response is ready to
>> be sent?
>> >
>> > Or is the stopwatch started when the first byte of the
>> request is received and stoped when the last byte of the
>> response has been sent? That is, it is including network
>> sending time?
>> From the source code for httpd-2.2.17,
>> modules/loggers/mod_log_config.c, line 650, %D is:
>>
>> apr_time_now() - r->request_time)
>>
>> "now" in this context means "the time at which the log line
>> is being written".  This is after all data has been
>> sent to the client (logging the amount of data sent the the
>> client is one of the things that can be logged).  Note
>> that the connection may remain open past the last byte being
>> sent to the client (keepalive, etc.).
>>
>> r->request_time gets set in server/protocol.c, line 617,
>> after the first non-blank line of the request (e.g., "GET /
>> HTTP/1.1\r\n")
>> made by the client is completely received.  This is
>> close to, but a little bit after (16 bytes after, in the
>> example I just gave) the first byte of the request was
>> received.  So the time to receive the first line of the
>> request is not counted in %D, but the time to receive any
>> subsequent lines of the same request are counted.
>>
>> I hope this helps.
>>
>
> Well, I'm still a little confused.
> I'm trying to find out why the accesslog shows the line
>
>
> ipA [31/Mar/2011] "GET /file.jpg HTTP/1.0" 200 42981 "-" "ApacheBench/2.3" 3560
> ipB [31/Mar/2011] "GET /file.jpg HTTP/1.0" 200 42981 "-" "ApacheBench/2.3" 93574
>
> (the ipA is much "closer" to the server than ipB).

What part do you think is inconsistent?

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