On 11/7/2012 2:36 PM, Marek Potociar wrote:
>
> On Nov 7, 2012, at 8:14 PM, Jan Algermissen <jan.algermissen_at_nordsc.com
> <mailto:jan.algermissen_at_nordsc.com>> wrote:
>
>>
>> On Nov 7, 2012, at 7:59 PM, Bill Burke <bburke_at_redhat.com
>> <mailto:bburke_at_redhat.com>> wrote:
>>
>>>
>>>
>>> On 11/7/2012 11:50 AM, Jan Algermissen wrote:
>>>> Hi,
>>>>
>>>> do you have an estimate what the overhead of using an AsyncResponse
>>>> is, if you send back a sync. response for the majority of cases?
>>>>
>>>> Use Case:
>>>>
>>>> Implement a resource method that retains the opportunity for
>>>> handling a request asynchronously but decides thatonly when the
>>>> method is actually invoked. IOW, when the method determines that a
>>>> synchronous response is fine, it simply invokes the async response
>>>> right away.
>>>>
>>>> Does that significanly affect performance or resource usage?
>>>
>>> I don't know. I could do a mini bench vs. JBoss Web Servlet
>>> container, but I"m too lazy.
>>>
>>> BTW, I have a similar use case that I've discussed before:
>>>
>>> @POST
>>> void post(@Suspended AsyncResponse res) {
>>>
>>> res.resume(Response.status(202).build()); // 202, Accepted
>>>
>>> // do an expensive op.
>>>
>>> }
>>>
>>> In this case, the client gets a response immediately, while the
>>> server does something in the background. Really simple, no need for
>>> queues, threads, etc.
>>
>> Well, yes that is how you do async properly with HTTP :-)
>
> No, it is not. Assuming the the code above runs in the same container
> thread that is dedicated to processing incoming requests, in the code
> above you return the response to the client quickly, but you will still
> continue to occupy the request processing container thread for your
> long-runnning operation effectively cancelling out any positive effect
> of the async operation on the server-side.
>
> To do it right, you would have to do this instead:
>
To paint this as a fact is misleading. You have your own opinion here
that is definitely not shared by myself.
--
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com