As far as I know...

The recommendation to keep the session below the 4-5 kB limit comes from
clustering.

When you build a cluster for your webapp and specify "session failover", 
meaning that a session should be taken over by a running instance in the
cluster if the original instance crashes, then the session must be 
replicated everytime it changes to all instances in the cluster. This
session-replication usually scales well, IF the information to be broadcasted
does not exceed 4 kB.

At least that's what I was taught. I operate in WLS-area, but I believe WS is
behaving similar in that area (everybody is cooking with the same water ;-) ).

I know of applications that scale well with session up into the MB-area! Their
problem is not the memory on the mid-tier server. You just must give them all
the memory you can buy... These applications cache some data they must request 
from a backend. And the backend-mechanism make it perform and scale better when 
the data is cached in the session. But these apps are special cases!!! (Cost of
calling the backend must also be considered...).

hth
Alexander

-----Original Message-----
From: Frank Zammetti [mailto:[EMAIL PROTECTED]
Sent: Mittwoch, 9. Juni 2004 20:02
To: [EMAIL PROTECTED]
Subject: RE: Single ActionForm accross multiple Actions


I had that thought too, but I don't know enough about WebSphere to know if 
it does that all the time... I know that I just installed 5.0 on a test box 
and didn't have to set up a database or anything, so unless it (a) set one 
up itself and is using it "under the hood", or (b) is persisting to the file 
system, which I tend to doubt, then I'm thinking along the same lines as you 
I think, which is to say that this recommendation, while probably valid all 
the time, doesn't carry the same weight if session is in-memory only.

Can anyone shed more light on this?

Frank


>From: [EMAIL PROTECTED]
>Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
>To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
>Subject: RE: Single ActionForm accross multiple Actions
>Date: Wed, 9 Jun 2004 13:26:40 -0400
>
>http://www.redbooks.ibm.com/redbooks/pdfs/sg246176.pdf
>
>I'm not 100% sure, but it seems that the recommendation for session size
>being < 4-5K is targeted to the scenario where the server has to serialize
>the session for persistence.
>
>Dennis
>
>
>
>
>
>"Frank Zammetti" <[EMAIL PROTECTED]>
>06/09/2004 01:10 PM
>Please respond to
>"Struts Users Mailing List" <[EMAIL PROTECTED]>
>
>
>To
>[EMAIL PROTECTED]
>cc
>
>Subject
>RE: Single ActionForm accross multiple Actions
>
>
>
>
>
>
>Very interesting (in a bad way for me!)... does anyone know if there is an
>
>easy way to see exactly how big the session object is at any given point
>in
>time?  Preferably something not specific to WebSphere... is there a method
>
>of session I'm unaware of that might help?
>
>Frank
>
>
> >From: "Yulin Zhao" <[EMAIL PROTECTED]>
> >Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> >To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> >Subject: RE: Single ActionForm accross multiple Actions
> >Date: Wed, 9 Jun 2004 11:57:49 -0500
> >
> >
> >
> >
> >Regarding WebSphere session performance, IBM redbook sg246176 chapter
>15.10
> >has
> >some details that might help you. We use WAS4 so that's for WAS4.
> >Here is some note from it:
> >"In general the best performance will be realized with session objects
> >that are less than 2 KB in size. Once the session object starts to exceed
>
> >4-5
> >KB in size, a significant decrease in performance can be expected."
> >
> >
> >
> >
> >[EMAIL PROTECTED] on 06/09/2004
>11:07:58
> >AM
> >
> >Please respond to "Struts Users Mailing List" <[EMAIL PROTECTED]>
> >
> >To:   [EMAIL PROTECTED]
> >cc:    (bcc: Yulin Zhao/FBFS)
> >
> >Subject:  RE: Single ActionForm accross multiple Actions
> >
> >
> >
> >I wasn't doubting you, as that standard practice rule is fairly
>well-known
> >outside WebSphere.  I think I've generally heard 32K as a limit, but
> >whatever, the point is keep session objects small.
> >
> >What I was asking was if there was some technical limitation in WebSphere
>I
> >wasn't aware of.  I can't go re-architecting this particular application
> >now, so if I'm storing 64K per session I was curious if WebSphere was
>going
> >to choke on it.  I understand the performance implications and the server
> >resource implications, as I did when I took this path, but I wasn't sure
>if
> >there was something more I wasn't aware of.
> >
> >Thanks for the lnik in any case.  Although it's 95% stuff I knew already
>(a
> >couple of EJB points I hadn't considered), it's something I can pass out
>to
> >the more junior members of my staff.
> >
> >Frank
> >
> >
> > >From: "Enrique Medina" <[EMAIL PROTECTED]>
> > >Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >To: [EMAIL PROTECTED]
> > >Subject: RE: Single ActionForm accross multiple Actions
> > >Date: Wed, 09 Jun 2004 16:45:04 +0200
> > >
> > >I am sure about this problem, believe me.
> > >
> > >See
>http://www-3.ibm.com/software/webservers/appserv/ws_bestpractices.pdf
> > >
> > >
> > >>From: "Frank Zammetti" <[EMAIL PROTECTED]>
> > >>Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >>To: [EMAIL PROTECTED]
> > >>Subject: RE: Single ActionForm accross multiple Actions
> > >>Date: Wed, 09 Jun 2004 09:25:16 -0400
> > >>MIME-Version: 1.0
> > >>X-Originating-IP: [66.98.131.150]
> > >>X-Originating-Email: [EMAIL PROTECTED]
> > >>X-Sender: [EMAIL PROTECTED]
> > >>Received: from mail.apache.org ([209.237.227.199]) by
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> > >>with Microsoft SMTPSVC(5.0.2195.6824); Wed, 9 Jun 2004 06:27:06 -0700
> > >>Received: (qmail 19779 invoked by uid 500); 9 Jun 2004 13:27:00 -0000
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> > >>Received: from [64.4.27.56] (HELO hotmail.com) (64.4.27.56)  by
> >apache.org
> > >>(qpsmtpd/0.27.1) with ESMTP; Wed, 09 Jun 2004 06:26:59 -0700
> > >>Received: from mail pickup service by hotmail.com with Microsoft
> >SMTPSVC;
> > >>Wed, 9 Jun 2004 06:25:16 -0700
> > >>Received: from 66.98.131.150 by by8fd.bay8.hotmail.msn.com with
> >HTTP;Wed,
> > >>09 Jun 2004 13:25:16 GMT
> > >>X-Message-Info: JGTYoYF78jGOA3bTrliIqk5vRqlH20u2
> > >>Mailing-List: contact [EMAIL PROTECTED]; run by ezmlm
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> > >>List-Post: <mailto:[EMAIL PROTECTED]>
> > >>List-Id: "Struts Users Mailing List" <user.struts.apache.org>
> > >>Delivered-To: mailing list [EMAIL PROTECTED]
> > >>Message-ID: <[EMAIL PROTECTED]>
> > >>X-OriginalArrivalTime: 09 Jun 2004 13:25:16.0563 (UTC)
> > >>FILETIME=[33F46E30:01C44E25]
> > >>X-Virus-Checked: Checked
> > >>Return-Path:
>[EMAIL PROTECTED]
> > >>
> > >>Do you know the rational behind that WebSphere warning?  I mean, the
> > >>obvious answer is it uses up server resources and will use more as
>load
> > >>increases, but is there another reason you know of?  I ask because I
> >have
> > >>an application where we store quite considerably more than 16K without
>
> >any
> > >>problem.  We're currently running it under Tomcat but are migrating to
> > >>WebSphere 5, so this caught my attention.
> > >>
> > >>Frank
> > >>
> > >>
> > >>>From: "Enrique Medina" <[EMAIL PROTECTED]>
> > >>>Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >>>To: [EMAIL PROTECTED]
> > >>>Subject: RE: Single ActionForm accross multiple Actions
> > >>>Date: Wed, 09 Jun 2004 09:57:02 +0200
> > >>>
> > >>>I've been reading this thread of discussion and one question arises
>in
> >my
> > >>>mind that you probably has not taken into consideration.
> > >>>
> > >>>Is there any limit with session management in your application
>server?
> >I
> > >>>mean, Websphere, for example, warns you about storing more than 16K
>in
> > >>>session.
> > >>>
> > >>>To bypass this problem, there is a good alternative (to the best of
>my
> > >>>knowledge): create a Map where keys would be session IDs and values
> >would
> > >>>be data (this would lead to the need of creating a wrapper for all
>your
> > >>>data). Then, this Map could be placed in application context, servlet
> > >>>context (in case of Struts which only uses one ActionServlet) or even
>
> >as
> > >>>a static Map shared by all users in the application server (of
>course,
> > >>>with no clustering at all).
> > >>>
> > >>>I would be delighted to hear some comments and suggestions in this
> > >>>solution.
> > >>>
> > >>>Enrique Medina.
> > >>>
> > >>>
> > >>>>From: "Frank Zammetti" <[EMAIL PROTECTED]>
> > >>>>Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >>>>To: [EMAIL PROTECTED]
> > >>>>Subject: RE: Single ActionForm accross multiple Actions
> > >>>>Date: Tue, 08 Jun 2004 22:02:01 -0400
> > >>>>MIME-Version: 1.0
> > >>>>X-Originating-IP: [68.81.51.228]
> > >>>>X-Originating-Email: [EMAIL PROTECTED]
> > >>>>X-Sender: [EMAIL PROTECTED]
> > >>>>Received: from mail.apache.org ([209.237.227.199]) by
> >mc3-f6.hotmail.com
> > >>>>with Microsoft SMTPSVC(5.0.2195.6824); Tue, 8 Jun 2004 19:02:13
>-0700
> > >>>>Received: (qmail 97286 invoked by uid 500); 9 Jun 2004 02:02:37
>-0000
> > >>>>Received: (qmail 97272 invoked by uid 99); 9 Jun 2004 02:02:36 -0000
> > >>>>Received: from [64.4.27.85] (HELO hotmail.com) (64.4.27.85)  by
> > >>>>apache.org (qpsmtpd/0.27.1) with ESMTP; Tue, 08 Jun 2004 19:02:36
> >-0700
> > >>>>Received: from mail pickup service by hotmail.com with Microsoft
> > >>>>SMTPSVC; Tue, 8 Jun 2004 19:02:01 -0700
> > >>>>Received: from 68.81.51.228 by by8fd.bay8.hotmail.msn.com with
> >HTTP;Wed,
> > >>>>09 Jun 2004 02:02:01 GMT
> > >>>>X-Message-Info: JGTYoYF78jEng6W3tuLSY7svF94DHMWf
> > >>>>Mailing-List: contact [EMAIL PROTECTED]; run by ezmlm
> > >>>>Precedence: bulk
> > >>>>List-Unsubscribe: <mailto:[EMAIL PROTECTED]>
> > >>>>List-Subscribe: <mailto:[EMAIL PROTECTED]>
> > >>>>List-Help: <mailto:[EMAIL PROTECTED]>
> > >>>>List-Post: <mailto:[EMAIL PROTECTED]>
> > >>>>List-Id: "Struts Users Mailing List" <user.struts.apache.org>
> > >>>>Delivered-To: mailing list [EMAIL PROTECTED]
> > >>>>Message-ID: <[EMAIL PROTECTED]>
> > >>>>X-OriginalArrivalTime: 09 Jun 2004 02:02:01.0481 (UTC)
> > >>>>FILETIME=[C0FB5790:01C44DC5]
> > >>>>X-Virus-Checked: Checked
> > >>>>Return-Path:
> >[EMAIL PROTECTED]
> > >>>>
> > >>>>You can set the scope attribute of your action mappings to session,
> >then
> > >>>>you don't have to do the code you have below.  The form instance
>that
> >is
> > >>>>passed into execute() will either be what was in session, or a newly
> > >>>>created one.
> > >>>>
> > >>>>I'm not sure about the answer to the second part of your question,
>but
> > >>>>I'm about 99.99% sure you can still use it (anyone else verify?)
> > >>>>
> > >>>>Frank
> > >>>>
> > >>>>
> > >>>>>From: "Kunal H. Parikh" <[EMAIL PROTECTED]>
> > >>>>>Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >>>>>To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]>
> > >>>>>Subject: RE: Single ActionForm accross multiple Actions
> > >>>>>Date: Wed, 9 Jun 2004 10:34:27 +1000
> > >>>>>
> > >>>>>Great ...... thanks for all the responses...
> > >>>>>
> > >>>>>I think I will go with the ActionForm stored in session-scope.
> > >>>>>
> > >>>>>Just wanting to confirm, that I will need to perform the following
> >code
> > >>>>>changes:
> > >>>>>
> > >>>>>==================
> > >>>>>public ActionForward execute( ActionMapping actionMapping,
>ActionForm
> > >>>>>actionForm, HttpServletRequest httpServletRequest,
> >HttpServletResponse
> > >>>>>httpServletResponse ) throws Exception
> > >>>>>{
> > >>>>>     actionForm =
> >httpServletRequest.getSession().getAttribute("myForm");
> > >>>>>     // ...
> > >>>>>     // normal code follows!!!
> > >>>>>}
> > >>>>>==================
> > >>>>>
> > >>>>>Also, would I be correct in saying that I will be unable to use the
> > >>>>>ValidatorActionForm.
> > >>>>>
> > >>>>>
> > >>>>>TIA,
> > >>>>>
> > >>>>>Kunal
> > >>>>>
> > >>>>>
> > >>>>>-----Original Message-----
> > >>>>>From: Frank Zammetti [mailto:[EMAIL PROTECTED]
> > >>>>>Sent: Tuesday, 8 June 2004 23:21
> > >>>>>To: [EMAIL PROTECTED]
> > >>>>>Subject: RE: Single ActionForm accross multiple Actions
> > >>>>>
> > >>>>>This is more or less what a session-scope ActionForm is for.  As
>long
> > >>>>>as the
> > >>>>>
> > >>>>>ActionForm class contains all the properties and methods for all
>the
> > >>>>>screen
> > >>>>>it will service, just putting it in session I think is your best
>bet.
> > >>>>>As
> > >>>>>someone else said, hidden form fields are your other choice.
> >Actually,
> > >>>>>you
> > >>>>>could also store the data temporarily to a database, but if you
>would
> > >>>>>even
> > >>>>>consider that, session is really the right answer.
> > >>>>>
> > >>>>>Frank
> > >>>>>
> > >>>>>
> > >>>>> >From: "Kunal H. Parikh" <[EMAIL PROTECTED]>
> > >>>>> >Reply-To: "Struts Users Mailing List" <[EMAIL PROTECTED]>
> > >>>>> >To: "'Struts Users Mailing List'" <[EMAIL PROTECTED]>
> > >>>>> >Subject: Single ActionForm accross multiple Actions
> > >>>>> >Date: Tue, 8 Jun 2004 12:08:25 +1000
> > >>>>> >
> > >>>>> >Hi All!
> > >>>>> >
> > >>>>> >I want to maintain a single ActionForm across multiple Actions.
> > >>>>> >
> > >>>>> >I want to get the info from the user in a step-by-step manner,
>but
> > >>>>>only
> > >>>>> >wanna talk to the SessionBean at the end when they hit "confirm".
> > >>>>> >
> > >>>>> >The alternative that I can think of is writing a JavaBean with
>all
> > >>>>>the
> > >>>>> >properties, and pass the JavaBean around as a session attribute.
> > >>>>> >
> > >>>>> >Any one have a better solution ?
> > >>>>> >
> > >>>>> >
> > >>>>> >TIA,
> > >>>>> >
> > >>>>> >Kunal
> > >>>>> >
> > >>>>> >
> > >>>>> >
> > >>>>>
> > >---------------------------------------------------------------------
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