ISAPI Filter fails in load testing

Hi,

I have created a simple ISAPI filter which will do a 302 Redirect to a
new URL generated by manipulating the requested URL. When i test this
ISAPI on IIS under Load testing then the test clients are showing
'zero' response time after first three minutes. At this point of time i
also tried to check manually doubting whether that is because of any
error. when i browsed manually i received an "Internal Server Error".

I have done locking in the ISAPI using Critical Sections as i have seen
some mixing of request URLs when it performs the manipulation on the
requested URL.

Should we make our own locking or threading mechanism or IIS will take
care of this threading?

I felt the ISAPI filter might have got crashed. Is this the reason or
something else. Can somebody tell me how to diagnose this problem ?

Thanks in advance.

Pat
Wed Feb 22 12:27:18 CST 2006

For an ISAPI filter you need to assume that you can have multiple threads
entering any given function at a time. The filter is responsible for it's
internal data structures and ensuring that synchronization (via whatever
locking mechanism is appropriate). A filter may also create it's own thread
pool and post work to those threads, but if it does so then it must also
handle the re-synching of the response.

I think you need to debug the filter and determine the root cause of the
load problem. There is no indication that the problem is with threading or
locking or what have you any more than any other possible cause - potential
corruption that only manifests itself after 'X' hits where X is reached much
faster under load.


Pat



"Chandra Sekhar" <darbha.sekhar@gmail.com> wrote in message
news:1140611238.017490.20050@g43g2000cwa.googlegroups.com...
> Hi,
>
> I have created a simple ISAPI filter which will do a 302 Redirect to a
> new URL generated by manipulating the requested URL. When i test this
> ISAPI on IIS under Load testing then the test clients are showing
> 'zero' response time after first three minutes. At this point of time i
> also tried to check manually doubting whether that is because of any
> error. when i browsed manually i received an "Internal Server Error".
>
> I have done locking in the ISAPI using Critical Sections as i have seen
> some mixing of request URLs when it performs the manipulation on the
> requested URL.
>
> Should we make our own locking or threading mechanism or IIS will take
> care of this threading?
>
> I felt the ISAPI filter might have got crashed. Is this the reason or
> something else. Can somebody tell me how to diagnose this problem ?
>
> Thanks in advance.
>

Shadul
Mon Mar 17 01:12:18 CDT 2008

Hmmm....I had the same issue sometime back.
Can you please share your kind so that we can figure it out

From http://www.developmentnow.com/g/59_2006_2_0_0_702292/ISAPI-Filter-fails-in-load-testing.ht

Posted via DevelopmentNow.com Group
http://www.developmentnow.com

David
Tue Mar 18 01:26:09 CDT 2008

On Mar 16, 11:12=A0pm, Shadul<shadulnar...@gmail.com> wrote:
> Hmmm....I had the same issue sometime back.
> Can you please share your kind so that we can figure it out.
>
> Fromhttp://www.developmentnow.com/g/59_2006_2_0_0_702292/ISAPI-Filter-fai.=
..
>
> Posted via DevelopmentNow.com Groupshttp://www.developmentnow.com


You should be able to easily do the redirection without critsec/locks
successfully.

Without seeing the filter source code, it would be difficult to
suggest a solution since it is really very straight forward.


//David
http://w3-4u.blogspot.com
http://blogs.msdn.com/David.Wang
//