Re: Confused about ASP, "sessions", and queuing of multiple requests

From: Ken Schaefer (kenREMOVE_at_THISadOpenStatic.com)
Date: 02/24/04 

Date: Tue, 24 Feb 2004 17:06:34 +1100

If you start a new instance of IE, then it does not share any in-memory
cookies (include ASP session state cookie) with the first IE instance. As
far as IIS is concerned, this is two separate ASP sessions. That is why you
are probably seeing parallel processing.

Cheers
Ken

"Ohaya" <Ohaya@NO_SPAM.cox.net> wrote in message
news:ezBHIqp%23DHA.3500@tk2msftngp13.phx.gbl...
: Sylvain,
:
: BTW, I forgot to mention:
:
: If I run my Waitfor test with 2 different instances of IE (on same
machine,
: but 2nd IE started from Start, not using Ctrl-N) simultaneously, I see
: Requests Executing in Perfmon as 2, i.e., in this situation, IIS *IS*
: apparently processing both requests simultaneously/in parallel.
:
: Like I said, I'm confused about what is different (specifically) between
the
: above test, and generating multiple HTTP requests from a single IE
: instance...
:
:
:
: "Ohaya" <Ohaya@NO_SPAM.cox.net> wrote in message
: news:OiJzRkp%23DHA.2520@TK2MSFTNGP11.phx.gbl...
: > Sylvain,
: >
: > Thanks for responding...
: >
: > Re. Waitfor, I just installed it for the test I described.
: >
: > Sorry if I'm being obtuse. I think I understand that one IE instance
can
: > generate multiple HTTP requests into IIS, e.g., in the instances that
you
: > described. In our case, I think your example of setting an IMG SRC to
an
: > ASP is exactly what we have, with multiple of these IMGs on one page.
: >
: > But, I guess I'm still unclear about when IIS/ASP will or will not
handle
: > these multiple requests in a "queuing" fashion vs. not in a queuing
: fashion.
: >
: > What exactly determines this? As I mentioned, the posts I've seen
vaguely
: > mention "in the same session", without clearly defining what they mean
by
: a
: > "session".
: >
: > Actually, the reason that I'm chasing all of this around is that we are
: > running IIS on a multiprocessor server. With the IE client firing
: multiple
: > requests to IIS, we thought that the multiple requests from IE would be
: > spread across the multiple processors.
: >
: > But on our production server, instead, for a given user operation at the
: > IE/client end, which, again, creates several HTTP requests to IIS, we're
: > seeing CPU activity on 1 CPU, then the next CPU, then the next CPU,
etc.,
: > until the user operation is complete.
: >
: > The conclusion we're coming to is that for some reason ASP on the
: production
: > server is not handling the multiple requests "in parallel", but rather
: > queuing the requests (we see the parallel processing on a different
: > multiprocessor server that we use for testing, but not on the production
: > machine).
: >
: > We just cannot figure out what is different between these 2 machines
that
: > would cause queuing the requests in one case, but not in the other.
: >
: > Thanks,
: > Jim
: >
: > "Sylvain Lafontaine" <sylvain aei ca (fill the blanks, no spam please)>
: > wrote in message news:O7nX9Np%23DHA.688@tk2msftngp13.phx.gbl...
: > > That's true since IIS 3.0 and there are occasions when you don't need
to
: > > make quick refresh to see it in action.
: > >
: > > For example, this is necessary when the IE is making simultaneous
: requests
: > > to the IIS. Exemple of this are when you are dividing your page using
: > > Frameset: each frame contains one HTML page as its source. Refreshing
a
: > > frameset then require to ask the server for more than one HTML page.
: > >
: > > Another example is when the source of an objet is an ASP page, like
: this:
: > >
: > > <img src="get_the_image.asp">
: > >
: > > The use of Javascript and of other advanced facilities for requesting
: data
: > > from one or more ASP pages also rise the possibilities of having
: multiple
: > > simultaneous requests to the web server. It is clear from those
example
: > > that the server cannot run these requests in parallele because of the
: > > possibility that the codes inside theses pages can make contradictory
: > > changes to Session variables, global variables and/or other objects,
: like
: > > backend requests to a SQL-Server. This should clear any confusion
into
: > your
: > > mind.
: > >
: > > By the way, using things like WaitFor and others objets for timing in
: ASP
: > > can result in a severe degradation of performance from the IIS and
their
: > > usages must be reserved to the cases when they are strictly necessary.
: > >
: > > S. L.
: > >
: > > "Ohaya" <Ohaya@NO_SPAM.cox.net> wrote in message
: > > news:u0nrjZo%23DHA.552@TK2MSFTNGP11.phx.gbl...
: > > > Hi,
: > > >
: > > > I'm trying to understand a situation where ASP seems to be
"blocking"
: of
: > > > "queuing" requests. This is on a Win2K Advanced Server, with IIS5.
: > > >
: > > > I've seen some posts (e.g.,
: > > >
: > >
: >
:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=Tidy7IDbDHA.2108%40cpmsftngxa06.phx.gbl)
: > > > that indicate that ASP will queue up requests when they come in with
: the
: > > > same "session".
: > > >
: > > > My first question is "Can someone confirm that this is true?" (see
: > below).
: > > >
: > > > My second is regarding what "same session" means in this context?
: > > >
: > > > Several of the posts that I've seen with respect to this queuing
just
: > say
: > > > "session", but I've also seen some posts that say "ASP session", and
: > which
: > > > specifically mention "the ASP Session object". This latter
reference
: > > ("ASP
: > > > Session object") is more precise, but my testing (again, see below)
: > seems
: > > to
: > > > indicate that this interpretation of "session" is not "ASP Session
: > > object".
: > > >
: > > > Here's the test that tried:
: > > >
: > > > 1) I installed the Waitfor from ServerObjects
: > > > (http://www.serverobjects.com/products.htm), and created a small
: > > "text.txt"
: > > > file in c:\.
: > > >
: > > > 2) I put Waitfor.asp in my website.
: > > >
: > > > 3) I ran Performance Monitor and added the "Requests Queued" counter
: > > >
: > > > 4) Using IE, I went to http://myserver/waitfor.asp
: > > >
: > > > 5) Once it connected, I started clicking the IE Refresh button
: > > >
: > > >
: > > > As I clicked the IE Refresh button, I could see the "Requests
Queued"
: > > > counter climb in Performance Monitor.
: > > >
: > > > The above test SEEM to at least indicate that ASP will *INDEED* only
: > > process
: > > > a single request from IE, i.e., that ASP *IS* queuing, but I'm still
: > > > confused about under what circumstances this queuing will happen
(what
: > > does
: > > > "session" mean in this context?).
: > > >
: > > > Can someone clarify this?
: > > >
: > > > Thanks, and apologies for both the cross-post and somewhat long
: post...
: > > >
: > > >
: > >
: > >
: >
: >
:
: