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Re: [XP] Re: Architecture for XP and scalable web sites

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  • Ron Jeffries
    ... With all due respect, I believe the above to be almost exactly incorrect. The worst that can happen if a big technology is chosen is that you get to market
    Message 1 of 22 , Jan 1, 2001
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      At 02:55 AM 1/2/2001 +0000, it seemed like Keith Richardson wrote:
      >The worst that can happen if the most
      >scalable technology is selected is the project takes longer to
      >implement and the deployment costs are slightly higher. The worst
      >that can happen if we go for lightweight solutions is that we find
      >the system is unusable when it eventually gets deployed. That would
      >be bad!

      With all due respect, I believe the above to be almost exactly incorrect.

      The worst that can happen if a big technology is chosen is that you get to
      market late, lose market share, and don't learn what people really want
      until it is too late. The worst that can happen if you go for lightweight
      solutions is that you have to beef it up upon deployment. But you find that
      out about a week after you start.

      Flexibility is better than planning, every time.

      Ronald E Jeffries
      http://www.XProgramming.com
      http://www.objectmentor.com
    • Glen B. Alleman
      Flexibility versus planning? ... critical (realtime shop floor control) or is it informational to a non-critical set of users? That is a big range of
      Message 2 of 22 , Jan 1, 2001
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        Flexibility versus planning?

        Here's some questions that may help clarify the situation:

        >>What is the context of the problem here?
        >>Where are the boundaries of your recommendation here?
        >>Where in the overall scheme of things does this system fit? Is it mission
        critical (realtime shop floor control) or is it informational to a
        non-critical set of users? That is a big range of "domain."

        The problem described by the original poster was a bit vague I agree. The
        manufacturing domain problems of "scalability estimates" are common,
        serious, and at the same time unknown without a lot of leg work. In a large
        manufacturing systems, "massive customization" is supported by a
        "configurator" based BOM system. See http://www.configsc.com/logia2.htm as
        an example of such a system. This is not the best, there are others (I2
        being a better one). This process can whipsaw the transaction rates by 2 to
        3 orders of magnitude when a simple "build to order" configuration is
        changed by marketing in an attempt to reposition a product line. The sizing
        impacts on this type of plant or shop floor system are a challenge for the
        experts, let along someone just getting started in the development of a
        plant data management system.

        This fellow needs to perform some analysis to determine the boundaries of
        the problem before embarking on ANY development method. He needs to get a
        strategy of how to scale the system "if and when" scaling is needed. If it
        is not needed, fine, but if it is then the system must be capable of
        performing this scaling without disruption to the ongoing business.

        If it is an on going business, then there are some CRUD stats somewhere,
        even if they have to be gathered by hand. Those then are used to "size" the
        solutions and determine the underlying technology needs. This is really
        simple IT Strategy stuff. There is definitely missing information in this
        case, which will most likely cause problems down stream. He's in no position
        to pick any technology without first understanding the processes and the
        data that they touch.

        Glen B Alleman
        Niwot Ridge Consulting

        "Every even number greater than 2 is the sum of two primes"


        >-----Original Message-----
        >From: Ron Jeffries [mailto:ronjeffries@...]
        >Sent: Monday, January 01, 2001 8:28 PM
        >To: extremeprogramming@egroups.com
        >Subject: Re: [XP] Re: Architecture for XP and scalable web sites
        >
        >
        >At 02:55 AM 1/2/2001 +0000, it seemed like Keith Richardson wrote:
        >>The worst that can happen if the most
        >>scalable technology is selected is the project takes longer to
        >>implement and the deployment costs are slightly higher. The worst
        >>that can happen if we go for lightweight solutions is that we find
        >>the system is unusable when it eventually gets deployed. That would
        >>be bad!
        >
        >With all due respect, I believe the above to be almost exactly incorrect.
        >
        >The worst that can happen if a big technology is chosen is that you get to
        >market late, lose market share, and don't learn what people really want
        >until it is too late. The worst that can happen if you go for lightweight
        >solutions is that you have to beef it up upon deployment. But you
        >find that
        >out about a week after you start.
        >
        >Flexibility is better than planning, every time.
        >
        >Ronald E Jeffries
        >
      • Patrick Logan
        ... I would notice that this story is ambiguous.
        Message 3 of 22 , Jan 1, 2001
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          --- "Keith Richardson" <keith@s...> wrote:

          > How would you have handled the user story: "Must be able to
          > scale quickly to unpredictable levels when a new client wants
          > to deploy in a high load environment"?

          I would notice that this story is ambiguous.
        • Laurent Bossavit
          ... Wouldn t it be worse if you selected the most scalable technology, took longer to implement the project, *and* found the system didn t respond well to high
          Message 4 of 22 , Jan 2, 2001
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            > The worst that can happen if the most scalable technology is
            > selected is the project takes longer to implement and the
            > deployment costs are slightly higher. The worst that can happen if
            > we go for lightweight solutions is that we find the system is
            > unusable when it eventually gets deployed. That would be bad!

            Wouldn't it be worse if you selected the most scalable technology,
            took longer to implement the project, *and* found the system didn't
            respond well to high loads when deployed ?

            Do you have any guarantee that won't happen ? What steps can be
            taken to prevent this happening ?


            ========================================
            We aim to make simple things simple and
            complex things possible.
            ========================================
            Laurent Bossavit - Software Architect
            >>> laurent.bossavit@... <<<
            >>> 06 68 15 11 44 <<<
            >> ICQ#39281367 <<
            Agence Bless http://www.agencebless.com/
            ========================================
          • Keith Richardson
            ... What a great forum - I posted a message at 10pm and got many great responses by 7am!! Either you guys never sleep or most of you are not is the EST time
            Message 5 of 22 , Jan 2, 2001
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              --- In extremeprogramming@egroups.com, "Laurent Bossavit"
              <laurent.bossavit@a...> wrote:
              > > The worst that can happen if the most scalable technology is
              > > selected is the project takes longer to implement and the
              > > deployment costs are slightly higher. The worst that can happen if
              > > we go for lightweight solutions is that we find the system is
              > > unusable when it eventually gets deployed. That would be bad!
              >
              > Wouldn't it be worse if you selected the most scalable technology,
              > took longer to implement the project, *and* found the system didn't
              > respond well to high loads when deployed ?
              >
              > Do you have any guarantee that won't happen ? What steps can be
              > taken to prevent this happening ?

              What a great forum - I posted a message at 10pm and got many great
              responses by 7am!! Either you guys never sleep or most of you are not
              is the EST time zone!

              The clear consensus is to keep the technology simple. Now to pick a
              robust and simple technology that works well with XP. Java is a much
              cleaner environment than ActiveX which would suggest not using MS-
              based development environment for IIS. A new question: what
              combination of development tools and deployment environment is best
              for a Web application built using XP? It should have a clean object
              model and a build environment that allows for rapid development cycle
              times. It must also be robust and a good performer because I don't
              want to be kludging around limitations or speed bottlenecks. What is
              being used for XP and how is it working?
              Keith Richardson
            • Chad Fowler
              ... cycle ... I would suggest that keeping your technology choice as open as possible is a good plan. This enables you to start with simplicity and grow when
              Message 6 of 22 , Jan 2, 2001
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                >
                > The clear consensus is to keep the technology simple. Now to pick a
                > robust and simple technology that works well with XP. Java is a much
                > cleaner environment than ActiveX which would suggest not using MS-
                > based development environment for IIS. A new question: what
                > combination of development tools and deployment environment is best
                > for a Web application built using XP? It should have a clean object
                > model and a build environment that allows for rapid development
                cycle
                > times. It must also be robust and a good performer because I don't
                > want to be kludging around limitations or speed bottlenecks. What is
                > being used for XP and how is it working?
                > Keith Richardson

                I would suggest that keeping your technology choice as open as
                possible is a good plan. This enables you to start with simplicity
                and grow when the need arises with less investment than a proprietary
                alternative would afford. We are successfully using and deploying
                Enhydra (http://www.enhydra.org) in a change-heavy iterative
                development environment. We have been very happy with its performance
                and flexibility (as well as its price--Open Source).
              • Stefan Schmiedl
                They work 40 hour weeks and hence have lots of free time on their hands.... :-) Stefan +---------+------------------------- ...
                Message 7 of 22 , Jan 2, 2001
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                  They work 40 hour weeks and hence have lots of free time on their
                  hands.... :-)

                  Stefan

                  +---------+-------------------------
                  | from | Keith Richardson <keith@...>
                  | to | extremeprogramming@egroups.com <extremeprogramming@egroups.com>
                  | date | 02.01.2001 16:13
                  | subject | [XP] Re: Architecture for XP and scalable web sites
                  +---------+-------------------------

                  K> What a great forum - I posted a message at 10pm and got many great
                  K> responses by 7am!! Either you guys never sleep or most of you are not
                  K> is the EST time zone!
                • astl@home.com
                  ... using ... the ... be ... to ... application ... by environment ... no ... solution ... traffic. ... features ... Do the user stories say don t lose my
                  Message 8 of 22 , Jan 12, 2001
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                    --- In extremeprogramming@egroups.com, "Chad Fowler"
                    <chadfowler@y...> wrote:
                    > --- In extremeprogramming@egroups.com, "Keith Richardson"
                    > <keith@s...> wrote:
                    > > Hello,
                    > > This forum has included several messages describing problems
                    using
                    > XP
                    > > with EJB, describing EJB as non-OO and other difficulties with
                    the
                    > > EJB architecture. A highly scalable web site must be able to
                    > automate
                    > > persistance of session and environment data, allow deployment to
                    be
                    > > easily adjusted and many other features that EJBs (and more
                    > > completely J2EE) provides. Are there other environments that have
                    > > proven to be better for developing highly scalable solutions with
                    > XP
                    > > or should I interpret these messages as saying that XP is not
                    > > applicable for these needs? Any XP success stories in this area
                    to
                    > be
                    > > shared?
                    > > Keith Richardson
                    >
                    > I think the point of a lot of these messages is that EJB is not, at
                    > least at the beginning of a project, (in most cases) the simplest
                    > thing that could possibly work. A well factored servlet
                    application
                    > provides session persistence (not sure what you mean
                    by "environment"
                    > in this context) and (being well factored) would also give
                    > flexibility for deployment options (things are logically decoupled,
                    > so they can be physically separated down the road).
                    >
                    > In the past, our developers were assuming that scalable-web-
                    > application == J2EE-all-the-way and just going with EJB from the
                    > start. This instroduced complexity in the code, the
                    > development/build process, and the application server deployment.
                    > This complexity invariably lead to various problems (more points of
                    > potential failure).
                    >
                    > The approach we've taken semi-recently with our developers is to
                    > say, "You are free to use EJB (and the rest of the J2EE baggage) if
                    > you can explain why you need it." What we've found so far is that
                    no
                    > one has ever needed it, and we haven't had any related problems.
                    > (And, our applications are *so* much easier to deploy and maintain
                    > now!) In the mean time, we've been trying to keep things well
                    > factored, so they could be easily moved to the more complex
                    solution
                    > should we ever hit the scalability barriers of this approach. My
                    > guess is that we won't ever get there.
                    >
                    > Of course, we're no amazon.com, but we get some pretty heavy
                    traffic.
                    >
                    > Just as an addendum, here's my XP zealot answer:
                    > "must be able to automate persistance of session and environment
                    > data, allow deployment to be easily adjusted and many other
                    features
                    > that EJBs (and more completely J2EE) provides" wasn't in my user
                    > stories. :)
                    >
                    > Chad

                    Do the user stories say "don't lose my data that I am entering just
                    because you want to update the servers?"

                    Ken.
                  • Alan Francis
                    ... ... Can we PLEASE try to keep the copied text to a minimum ? Even if the two new lines are the most
                    Message 9 of 22 , Jan 12, 2001
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                      --- In extremeprogramming@egroups.com, astl@h... wrote:
                      <a zillion lines of copied message>
                      <followed by....>
                      > Do the user stories say "don't lose my data that I am entering just
                      > because you want to update the servers?"

                      Can we PLEASE try to keep the copied text to a minimum ? Even if the
                      two new lines are the most insightful piece of observation yet, it's
                      still anooying to get massive emails full of copied stuff.

                      Maybe OMI could host an extremeprogramming wiki so conversations
                      could be conversations ? :-)

                      Alan
                    • Chad Fowler
                      ... If they do, then it s time to find the simplest solution that can satisfy the story--again, not limited to EJB (nor very likely to be).
                      Message 10 of 22 , Jan 13, 2001
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                        > > Just as an addendum, here's my XP zealot answer:
                        > > "must be able to automate persistance of session and environment
                        > > data, allow deployment to be easily adjusted and many other
                        > features
                        > > that EJBs (and more completely J2EE) provides" wasn't in my user
                        > > stories. :)
                        > >
                        > Do the user stories say "don't lose my data that I am entering just
                        > because you want to update the servers?"
                        >
                        > Ken.

                        If they do, then it's time to find the simplest solution that can
                        satisfy the story--again, not limited to EJB (nor very likely to be).
                      • Erik Meade
                        I mentioned this to Ward a few weeks ago, he said that Extreme Programming is on topic for his (The) Wiki http://www.c2.com/cgi/wiki?FrontPage -- Erik Meade
                        Message 11 of 22 , Jan 17, 2001
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                          I mentioned this to Ward a few weeks ago, he said that Extreme
                          Programming is on topic for his (The) Wiki
                          http://www.c2.com/cgi/wiki?FrontPage

                          --
                          Erik Meade emeade@...
                          Senior Consultant Object Mentor, Inc.
                          http://www.junit.org


                          -----Original Message-----
                          From: "Alan Francis" <alan@...>
                          Subject: Re: Architecture for XP and scalable web sites

                          Maybe OMI could host an extremeprogramming wiki so conversations
                          could be conversations ? :-)

                          Alan
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