Hi Sacha;
Thanks allot for the insightful reply. It was the answer that I long waited
for.
Given what you stated/explained:
"JBoss has a goal: to serve each request immediately. Consequently, if the
pool is empty, a new instance is created and, once the instance is returned
to the pool, the instance will be freed (and not returned back to the pool).
Thus, JBoss don't wait for an instance to become available to serve
concurrent requests."
J2EE Applications that are deployed on JBoss will not be able to guarantee a
specific performance at all times. In other-words; if I'm selling a J2EE
application product/solution that is deployed on JBoss within a client's
server machine, and the client requires that there would always be a
guaranteed performance (i.e. throughput) for each requesting/connecting
client to a particular ejb (bean) resource. JBoss goal stated above, would
take away the chance of me offering a solution/product application that
would optimally run, and meet the required performance on a particular
machine (available) resources, that could be stated as part of the
product's/solution's installation minimum requirements.
With this king of JBoss flexibility that you have stated, it's true that you
would accommodate all requesting (concurrent) clients, but this would be on
the expense of the overall performance that one would like to insure as a
minimum.
I realize that even in the J2EE spec. for v1.2 or v1.3 (Section 5.4.3) it
was not clearly required/specified how container (available instance bean)
pool resources should be managed/handled. However, since many of the other
J2EE vendor products that I have tried (i.e. WLS, iPlanet, Borland) operates
on this kind of performance configurational guarantee, where concurrent
clients will have to wait until available bean instance resources (that have
been configured with) are available, in order to reuse them (where it can't
share).
And since I'm really more interested in the use of JBoss for promoting
deployment of our application's solutions on it for our clients (for
obviouse reasons, especially cost and ease of use), is there a way to turn
this current (extended) concurrent JBoss handling off, and rather allow
additional requests (to the available instances within a pool) to wait until
(freed) bean instances are returned back to the pool..?
Or is the only way for me to currently address it if via modifying the
org.jboss.ejb.plugins.AbstractInstancePool.get() method that you have
outlined below. If so, is there other methods that I should also be
modifying, in order to insure that all bean's container types are behaving
the same?
Appreciate very much your thoughts and feedbacks. Thanks allot in advance.
Regards;
Jeff.
>From: "Sacha Labourey" <[EMAIL PROTECTED]>
>To: "jeff andrews" <[EMAIL PROTECTED]>,
><[EMAIL PROTECTED]>
>Subject: RE: [JBoss-dev] JBOSS EJB Container Bug ?!
>Date: Thu, 27 Dec 2001 17:56:03 +0100
>
>Hello Jeff,
>
>For you problem, take a look at
>org.jboss.ejb.plugins.AbstractInstancePool.get():
>
> public synchronized EnterpriseContext get()
> throws Exception
> {
> //DEBUG Logger.debug("Get instance "+this);
>
> if (!pool.empty())
> {
> mReadyBean.remove();
> return (EnterpriseContext)pool.pop();
> } else
> {
> try
> {
> return create(container.createBeanClassInstance());
> } catch (InstantiationException e)
> {
> throw new ServerException("Could not instantiate bean",
>e);
> } catch (IllegalAccessException e)
> {
> throw new ServerException("Could not instantiate bean",
>e);
> }
> }
> }
>
>
>As you can see, with this implementation, JBoss has a goal: to serve each
>request immediately. Consequently, if the pool is empty, a new instance is
>created and, once the instance is returned to the pool, the instance will
>be
>freed (and not returned back to the pool). Thus, JBoss don't wait for an
>instance to become available to serve concurrent requests.
>
> => the pool size will never exceed the size you indicate in your
>deployment
>descriptor *but* the number of active instances *may* be bigger if
>concurrent acccess require it.
>
> > What am I messing ?!! Please help.... As I have bean
> > struggling with this kind of a problem for over a month
> > now.
>
>And in 10 seconds of JBoss consulting you have your answer ;)
>
>Cheers,
>
>
>
> Sacha
>
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