|Another thing you did not mention is the hardware
|platform you are running on, and whether you are doing
|Web or Swing GUI. Don't count on WinTel platforms to
|handle a lot of entity bean instances. And if you are
|doing a Swing GUI with a high number of users the
|server (jboss anyway) may bog down with simultaneous
|threads (RMI Reference Implementation is in use at
|this time), one for each of the connections (as
|opposed to a pool of threads to handle a fixed number
|of connections and block all others until they can be
|handled). Again, hardware will play in here. For a
|huge Sun box, it may not really matter. jBoss has been
|tested agains this (seems like E4500) with "5000"
|simultaneous users. But don't count on WinTel giving
|you that. Depending on the server load dealing with
not so not so!
in fact the only one that didn't really do well was linux (obviously due to
the old kernel, not a limit in the new one)
but win2k went stably to 2000 clients (above he started puking) **on a
700Mhz athlon**.
Sure the e4500 with 3,36Ghz total (10 way) was kicking everyones butt when
you think about it ... 3.3/0.7=4.8 so.... 8000 clients on win2k?
this is off the cuff but interesting in my mind.
marc
|bean instances, connection thread overhead will just
|add to the overall load.
|
|In any event, if you have the bucks and market to do
|clustering of EJB servers on a kicking multiway Sun
|box, yeah you can scale it no matter what. In that
|case just buy the hardware and use CMP and get the app
|out to users! But if that's not you, you'll have to
|think about some of the other things I brought up.
|
|Hope this helps. Thought it would be best to give you
|some options rather than a docmatic viewpoint since I
|don't really know your system. :-)
|
|Vaughn
|
|
|From: "Kenworthy, Edward"
|<[EMAIL PROTECTED]> | Block address
|To: 'jBoss' <[EMAIL PROTECTED]>
|Subject: RE: [jBoss-User] jBoss: Can it cope with many
|bean classes?
|Date: Thu, 7 Dec 2000 08:38:59 -0000
|Reply-to: "jBoss" <[EMAIL PROTECTED]>
| Add Addresses
|
|If you have 400 different entity beans then it sounds
|like your entity
|beans
|are far too fine-grained (similarly for your session
|beans).
|
|[To give you a for instance, the system I am currently
|working on has
|of the
|order of 100 entities, but only 8 EJB entity beans. It
|has around 40
|session
|beans (session bean corresponds to use case in our
|system, and I am of
|the
|Ivar Jacobson, *BIG*, ie proper, Use Case school - so
|40 use case
|system is
|roughly an 40 man-year project, and multi-million
|pound).]
|
|The problem you will have is that to do anything
|realistic with a
|fine-grained system (eg 400 entities) will require the
|instantiation of
|many
|EJB entities and that is expensive in terms of both
|system resources
|and the
|app server having to manage all these teeny EJB
|entities. It migh be
|worth
|reviewing your design and seeing if you can cluster
|your entities
|together.
|Eg you may have Customer -->(many)Order -->
|(many)Product. Is Order
|really
|separate from Customer ? Probably not, you probaly
|only rarely (if
|ever)
|deal with it separately from Customer so perhaps Order
|(entity) and
|Customer
|(entity) should be combined into a single EJB entity.
|
|The mistake people often seem to make is mapping
|classes 1:1 to EJBs.
|EJBs
|are *components*. The mapping, particularly for EJB
|entities, I would
|expect
|to be many classes in one EJB.
|
|A simple rule of thumb to find you EJB entities that
|we've used is:
|what's
|the relationship ? association or aggregation, if the
|latter then
|you're
|probably looking at two classes in one EJB entity
|(doubly so if its a
|containment aggregation.) That of course is a
|technical way of saying
|look
|at the life-times and context. Is one ever used
|(instantiated) without
|the
|other ?
|
|Hope this helps :-) But probably not in the way you
|had hoped.
|
|Edward
|
|PS
|
|Oh and for all but the simplest systems, CMP is
|completely inadequate.
|it
|leads to you defining hundreds of tiny EJB entities
|that will perform
|like a
|dog :-) Use BMP.
|
|-----Original Message-----
|From: Bakker Ruben
|[mailto:[EMAIL PROTECTED]]
|Sent: 07 December 2000 07:43
|To: '[EMAIL PROTECTED]'
|Subject: [jBoss-User] jBoss: Can it cope with many
|bean classes?
|
|
|
|Hello everybody.
|
|We've building a large ERP-System and like are planing
|a transition
|from a
|custom CORBA App-Server to EJB. We currently have
|about 400 different
|EntityBeans and about 200 SessionBeans most of them
|stateful. Can jBoss
|cope
|with this? Is EJB in general designed for such large
|applications? Has
|anybody experience in building large applications with
|EJB (jBoss?)?
|
|Any answer is very much appreciated...
|Ruben
|
|
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