async pages and redirect

[=?Utf-8?B?cGI=?=]

I am having trouble doing a redirect in an async asp.net implemention.
Most of the time it works, but when it doesn't it just "hangs", the browser
never gets any return page. If I run it under the debugger, it works fine,
though every so often I get a HttpException.

System.Web.Http Exception was caught
ErrorCode=-2147024809
Message="An error occurred while communicating with the remote host. The
error code is 0x80070057."
Source="System. Web"
StackTrace:
at
System.Web.Host ing.ISAPIWorker RequestInProcFo rIIS6.FlushCore (Byte[] status,
Byte[] header, Int32 keepConnected, Int32 totalBodySize, Int32
numBodyFragment s, IntPtr[] bodyFragments, Int32[] bodyFragmentLen gths, Int32
doneWithSession , Int32 finalStatus, Boolean& async)
at System.Web.Host ing.ISAPIWorker Request.FlushCa chedResponse(Bo olean
isFinal)
at System.Web.Host ing.ISAPIWorker Request.FlushRe sponse(Boolean
finalFlush)
at System.Web.Http Response.Flush( Boolean finalFlush)
at System.Web.Http Response.Flush( )
at System.Web.Http Response.End()
at System.Web.Http Response.Redire ct(String url, Boolean endResponse)
at w2pagev.PageV.E ndPage(IAsyncRe sult ar) in
G:\inetpub\wwwr oot\w2pagev\pag e.aspx.vb:line 100

The exception is caught in the EndEventHandler .
I am using AddOnPreRenderC ompleteAsync to set this up.

[phil]

On Feb 23, 10:48 am, "John Saunders" <john.saunder s at trizetto.com>
wrote:

"pb" <p...@newsgroup s.nospamwrote in message

news:3A******** *************** ***********@mic rosoft.com...

"Steven Cheng[MSFT]" wrote:

Thanks for your followup Pb,

After got the code snippet you provided, I notice that your
implementation
is quite different as I expect. Yes, you haven't simply used the existing
asynccomponent s (like delegate or WebRequest...) and manually create a
normal sub thread to do the work.

And in addition to the "IAsyncResu lt" implmentation class, another thing
you haven't provided is your thread proc function. You need to ensure
the
passed in callback should be invoked at the end of your thread proc
function(when the task has finished). Also, I think the occasional hang
problem does be possible related to the IAsyncResult implementation. You
can try using Delegate.BeginI nvoke approach to run the same stuff to see
whether it will lead to the same behvior.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

This posting is provided "AS IS" with no warranties, and confers no
rights.

Steven-

a couple of things... i don't think i am having any more trouble with the
redirectnow that i've moved it (see previous code). i do, however,
experience "hangs" when running the new thread model under load (using
WCAT).
over the course of several hours, i will see ASP.NET restart several times
when it failed to respond to the IIS ping. i do not experience these hangs
when i switch to my old implementation (i have a simple switch that runs
it
asyncor not).

Make very certain that you have a try/catch block around all of your
threads. Otherwise, an unhandled exception will just quietly kill the
thread.

John- Hide quoted text -

- Show quoted text -

john,

that's an important point. if an exception aborts the thread before
it completes EndPage won't be called. what does ASP.NET do in that
case? does it just time out the initial thread that dispatched the
page (the CLR thread pool thread)? i imagine, even if it timed out
the dispatch thread that all the thread pool threads could be consumed
in this case and then ASP.NET would "hang"... and IIS would be forced
to restart it. i will make certain my thread always completes to the
caller regardless of what is does in between!

/phil

[Steven Cheng[MSFT]]

Thanks for your reply Pb,

I'll have a further check and test based on the code you provided. I'll
update you as soon as possible.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead
This posting is provided "AS IS" with no warranties, and confers no rights.

[Steven Cheng[MSFT]]

Hi Pb,

Sorry for the dely update. After some further research, I still haven't
been able to address the root cause of the issue. The difficulty here is
that the behavior is quite hard to test in development, and the underlying
cause require some low level debugging. After discussing with some other
engineers, we suggest you consider contact CSS for further troubleshooting
on this issue:

http://msdn.microsoft.com/subscripti...t/default.aspx

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead
This posting is provided "AS IS" with no warranties, and confers no rights.