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From Christopher Schultz <ch...@christopherschultz.net>
Subject Re: Tomcat 8 Application dispatcherServlet Stats
Date Thu, 14 Jan 2016 15:16:28 GMT
Theo,

On 1/14/16 5:53 AM, Theo Sweeny wrote:
> Hello Kyohei,
> 
> -----Original Message-----
> From: Kyohei Nakamura [mailto:nakamura.kyohei.lab@gmail.com]
> Sent: 14 January 2016 09:59
> To: Tomcat Users List <users@tomcat.apache.org>
> Subject: Re: Tomcat 8 Application dispatcherServlet Stats
> 
> What does "response time" mean?
> 
> The "Processing time" include a time that is from the end of service method of servlet
instance until the end of StandardWrapperValve#invoke().
> 
> 
> 2016-01-14 17:27 GMT+09:00 Theo Sweeny <theo.sweeny@avios.com>:
> 
>> Hello Kyohei,
>>
>> -----Original Message-----
>> From: Kyohei Nakamura [mailto:nakamura.kyohei.lab@gmail.com]
>> Sent: 14 January 2016 06:45
>> To: Tomcat Users List <users@tomcat.apache.org>
>> Subject: Re: Tomcat 8 Application dispatcherServlet Stats
>>
>> Hello
>>
>> The "Processing time" metric represents the execution time of
>> StandardWrapperValve#invoke().
>> This is the execution time of the servlet and filters.
>> This value of "Processing time" is the total time of each request
>> execution time.
>>
>> What is the dispatcherServlet?
>> If dispatcherServlet accept all request as a front controller(like
>> Spring's DispatcherServlet), then this value is the total execution
>> time of all request that the context receive.
>>
>>
>> 2016-01-13 20:19 GMT+09:00 Theo Sweeny <theo.sweeny@avios.com>:
>>
>>> Hello - at the moment stats can be found for Tomcat 8 web services
>>> using the manager UI /manager/status/all
>>>
>>> Is the "Processing time" metric found under dispatcherServlet [ / ]
>>> subsection, the total time take to serve all requests, including the
>>> response time for each request?
>>>
>>> Regards,
>>>
>>> Theo
>>
>> Does the total execution time for each request include the response time?
>>
>> Thank you,
>>
>> Theo
>>
> 
> I think indirectly you have answered my question. From a network
> perspective you have the initial connection time to send the request
> (request time), then you have the time to process the request, and
> finally response time back to the client. Both the processing time
> and response time for the purpose of this task are merged under the
> umbrella of response time. So going full circle - the
> dispatcherServlet Processing time fits the bill of response time.

There is a case where this might not actually give you what you are
looking for -- which sounds essentially like the amount of time the
server spent processing that request.

If StandardWrapperValve only times how long invoke() takes and (and I
haven't read the code, so I'm not sure) some component in Tomcat
executes *after* invoke() completes for the purposes of flushing any
buffered data back to the client, then "Processing Time" may be off by
the amount of time it takes Tomcat to flush those buffers back to the
client. If you have big buffers or slow clients, this could add up quickly.

-chris

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