Concurrent processing of ASP.NET pages

[Hitesh]

We all know that IIS and asp.net are suppose to be muti-threaded
applications running on a pre-emptive multi-tasking model. But, what I
have
found is that under the default installation of ASP.NET, aspx pages get

executed serially. I know that it's easy to say that this can't be
right,
but I have found threads where others have confirmed this same
behavior.


The situation is _very_ easy to reproduce. Simply place two aspx pages
on a
web site, on the one page put some code that will take a bit to execute
(say
a while loop) and on the other page simply put some text (perhaps
"hello").
Now open two browser windows, in the first browser open the long
running
page, now in the second window open the hello page. What you will find
is
that you will not receive the hello page until the long running page
completes and is sent to the browser. The pages are running serially
on the
server!


How does one configure asp.net so that the pages run under a preemptive

multitasking model?

 

[John Timney \(MVP\)]

The pages are not running serially, your requests are - and as they are from
the same client they are dealt with serially.

Fish about on google, but if I remember correctly this can happen if you
open IE and then do new window, both IE sessions are the same. Try running
IE and then run another instance of IE rather than a new IE window. You
should get a different session ID and thus non-sequential requests.

--
Regards

John Timney (MVP)
VISIT MY WEBSITE:
http://www.johntimney.com

 

[Hitesh]

Thanks John for correcting me.

I am using two different instances of IE. I mean with different
sessionID's.

Hitesh

 

[bruce barker \(sqlwork.com\)]

there are two causes for this.

1) the two browsers are using the same session. say you opened the second
one from IE's new window rather than from the start menu. asp.net serializes
accss to session.

2) IE limits the number of requests to the same server, so will serial the
requests. yucan bump this up in the registry.

-- bruce (sqlwork.com)

 

[Hitesh]

Bruce,

Point 1 is not the case with me.

Could you please give me some more detail on Point 2 .Actually i am
accessing a Page on which I am sending multiple async requests. But
response is coming seuentiall.

I found that IIS is hadling the request serially.

 

[George Ter-Saakov]

Somehow I am positive that point 1 is the case with you .
But anyway.
By default IE issues 4 simultaneous requests to the same server. All others
are put on hold.

It's done to prevent you killing your network with 100s simultaneous
requests if html page has 100s pictures on it.

Check http://www.speedguide.net/ they have a registry tweak that will bump
that number (4) up.

George.

 

[Hitesh]

I tried running the same scenario on the machine with windows 2003
server and IIS 6 installed. It is giving the expected results.Requests
are handled parallely and results are according to the default IE
settings


But on the machine having Windows XP and IIS 5.0 the requests are
handled serially as i mentioned.

I also tried running the same scenario on the machine having Dual
processor with windows XP and IIS 5.0.This is also giving the expected
result.


Did anyone of you is able to re-produce the same on your end?