[Seaside] Enterprise Software V Ecommerce [in
dirkdirk at gmail.com
Thu Feb 23 02:07:01 UTC 2012
Thanks for your thoughts and advice. I know Steve is familiar with GemStone
but I'm not sure whether he is aware of GLASS.
No doubt he'll have further queries when he sees your comments.
On 23/02/2012 10:07 AM, "James Foster" <Smalltalk at jgfoster.net> wrote:
> Hi Dirk,
> It is certainly true that having a relatively clean separation between the
> layers (infrastructure, domain, application, and UI) is a good design
> principle. And Steve is right that building a complex network of objects
> that cannot fit in memory is not very scalable.
> On the other hand, if you have a tool that allows you to act like you have
> a huge transactional object space that is shared by hundreds of concurrent
> sessions, where your "stored procedures" are written in Smalltalk, and
> Seaside support is built-in, then your prototype might not be so
> unrealistic. Have you heard of GemStone/S? Check out
> http://seaside.gemstone.com/, and the various links from there, including
> my blog at http://programminggems.wordpress.com/ and Dale's blog at
> Feel free to ask more detailed questions...
> On Feb 22, 2012, at 3:33 PM, dirk newbold wrote:
> > Hi all,
> > I’m a relative newbie (4 years) to programming and seaside, who
> > partnered up with some “old hands” (smalltalk/seaside is my first and
> > only language).
> > Initially we developed an Ecommerce (Istazaar) fashion platform for
> > designers to maintain their collections. We stagnated last year due
> > to the time restraints on the “old hands” and I then began developing
> > a web based Enterprise Software (Vivport) platform for
> > document-management/knowledge-management/emails/tasks.
> > We now have two ventures at relatively equal stages of development.
> > I believe the Enterprise Software (Vivport) platform is the more
> > innovative however, now that Steve (one of the “old hands”) has some
> > time again he has been able to review its development (which
> > unfortunately I built unsupervised) and has major concerns in relation
> > to deploying this venture.
> > Instead of building the database; then building middleware, then UI;
> > I’ve basically just built a UI, Steve’s concerns with the outcomes of
> > this development process are outlined in his email to me below.
> > We were wondering if the smalltalk/seaside community has any views on
> > Steve’s concerns below that may influence our decision on which
> > venture to proceed with.
> > The platform has been developed to freely change between the user’s
> > personal account and their company(ies) account. The personal
> > accounts are free so we would be attempting to server many users.
> > Any advice in relation to users/image, persistence, database, general
> > deployment etc for this type of venture (essentially a beefed up
> > gmail/cloud environment) would be greatly appreciated.
> > Thanks for your time.
> > Cheers,
> > Dirk
> > ---------- Forwarded message ----------
> > From: Steven Berryman <Steven at berrymanelectrical.co.uk>
> > Date: Sat, Feb 18, 2012 at 6:07 AM
> > Subject: RE: Vivport V Istazaar
> > To: dirk newbold <dirkdirk at gmail.com>
> > Dirk,
> > As mentioned I’m concerned with the approach you have taken with
> > Vivport and in one way this technology can lead you into a false sense
> > of how easy things are (trust me you couldn’t have done it in .NET or
> > java without infrastructure). The difference with the ecommerce site
> > is that there is little shared data and I knew that the only real
> > issue was storing users but that would be a simple mapping issue to a
> > table. Even the registered objects were designed to make storing in
> > the database easier so objects didn’t directly hold onto a registered
> > object. What you have built is a very complicated network of objects
> > for the benefit of the UI which for a prototype is great but would
> > never work in the real world. The type of project you are building
> > with Vivport is infrastructure and in one way the last thing you
> > should have done is the UI. One system I worked on had 3-4 months of
> > designing the infrastructure before a line of code was written.
> > The problem you have is that you have assumed that all objects would
> > be in memory and are accessible via threads and this just isn’t
> > possible. If I look at my local Microsoft exchange server it’s
> > currently 50GB for 5 users and the machine only has 4GB of ram so not
> > only do you need to deal with large amounts of data but you have not
> > addressed any multi-threading issues. For example Smalltalk provides
> > structures such as SharedQueue to deal with any shared data in the
> > memory and I’m guessing you didn’t use these? When everything is in
> > memory the world is very easy but for a system like yours you would
> > need to start with the database and design the schema. Most searches
> > would be done directly in sql (assuming you are using a relational
> > database) so that way you reduce the amount of data going to the
> > client. So when you open up Microsoft Outlook it will run a query on
> > the database to get your inbox and the email headers so you don’t pull
> > large amounts of data across the network. As you start to click on
> > emails it will pull the data over as required.
> > So here is an example to show multi-threading issues (I have not used
> > your code but I’m sure you get the point)
> > Lets’ assume you have a folder with 10 items
> > Dirk - actions Danny - actions
> > folder items do: [ :item
> > “goes through this loop twice”
> > delete the last
> > item in the folder
> > “code falls over because the last element
> > in the collection does not exist.” ]
> > I’m sure you could try something like the above but you would need to
> > put in a break point in the Dirk loop so you could then go in and to
> > the removal from a different session. Now imagine the same thing with
> > 5,000 users logged into your server all running threads across your
> > code. Your code would have to be thread safe and this is not a simple
> > task especially trying to do it on code not designed that way from the
> > beginning. You could end up locking up all the other sessions if you
> > don’t carefully design and keep your critical sections to a minimum.
> > If you are using collections that are hashed they will fail in very
> > strange ways if you have other threads removing or adding items as you
> > are iterating through the collection. Basically in the ecommerce site
> > we could sort of ignore the shared data issue as we shared very little
> > data between sessions.
> > Also you have added features that would be very expensive when using
> > databases. For example the running man relies on the status of some
> > piece of data and of course when everything is in the same memory
> > space this is easy. In a database you would have to cross a
> > transaction boundary and even the fastest database servers we have
> > (costing 200k per server) you would be lucky for a single transaction
> > to take between 1-10 milliseconds (costly when you scale up users and
> > make too many database calls). This is why Microsoft exchange works
> > the way it does as you can imagine how slow it would be if 5000 people
> > logged into the server at the same time. So for most document
> > management systems they would have a large database at the back end
> > and all the searches would be done as stored procedures that could be
> > based on some proprietary algorithm and none of this would be done in
> > the language itself such as Smalltalk. Until you have a database
> > schema designed you can’t even think about the UI.
> > If you want to prove to yourself then try and create 100,000 users all
> > with about 10MB of data and test to see if it works. See if you can
> > log in a few sessions and send emails around.
> > With the ecommerce site I could imagine how to add a database at the
> > backend because it would be very simple. I would have no idea how you
> > get this into a database even if you used an object database you would
> > still need a defined object model. It’s also the reason why I liked
> > the ecommerce site as it would be simple from the database end as it
> > would only contain users, basic static data and designer’s data. Also
> > I can see how we could have multiple servers to handler more traffic
> > with the ecommerce site but would have no idea how we could do the
> > same with your design.
> > Hope this makes sense. Let’s catch up next week.
> > Steve
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