Again, this is still vendor specific. For instance, in WL entity beans
would not be load balanced - once you get a proxy to an entity bean, you
will talk to the same node in the cluster. For stateless session beans, the
proxy object actually implements the load balancing (round robin, by
default) - this means that the same reference can be dispatching requests to
different nodes.
-----Original Message-----
From: Nirvana(on behalf of vaheesan Selvarajah)
[mailto:[EMAIL PROTECTED]]
Sent: Thursday, September 13, 2001 11:50 AM
To: [EMAIL PROTECTED]
Subject: Re: IntialContext
but krishnan in your code once a ref to a home is obtained then it is kept
in the hashtable and when another client invokes the same bean then the same
ref which was held in the hashtable would be returned which stops the
request to go to the next server in the cluster. right??? just like having a
lookup in JSP/Servlet init() methods.... hence no posibility for round
robin...
Am I right?
r
vahees
-----Original Message-----
From: Krishnan Subramanian <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Thursday, September 13, 2001 3:25 PM
Subject: Re: IntialContext
Senthoor,
Load balancing is again vendor specific. With some
products you need to do something extra - like creating
cluster aware stubs.
With our product (built on top of VisiBroker - a high
performant, scalable Corba implementation), clustering
is built into the architecture. So clustering is almost
easy as plugging in another server and load balancing
and failovers are immediately available. (our server
side and client side stubs are already 'smart')
You do raise an interesting point - which is load balancing
(btw that source code was used in a clustered environment).
Normally you would want a single client to talk to a server
and remain connected to that server for performance reasons.
If a single client had to alternate between a cluster of servers
for every method call, then performance would drop - simply
because of the cost of looking up and setting up a connection
to different servers. Of course multiple clients would round
robin (or some similar load balancing algorithm - but we use
round robin as a default) between servers. But to put a long
story short, yes - clustering is a vendor dependent feature
and you need to be aware of how the vendor implements it.
See
http://archives.java.sun.com/cgi-bin/wa?A2=ind0106&L=ejb-interest&P=R2508
for some more new terms and concepts :)
-krish
> -----Original Message-----
> From: A mailing list for Enterprise JavaBeans development
> [mailto:[EMAIL PROTECTED]]On Behalf Of Senthoorkumaran
> Sent: Thursday, September 13, 2001 8:07 AM
> To: [EMAIL PROTECTED]
> Subject: Re: IntialContext
>
>
> I reffered to the link you have specified below. Don't you think that
> methodology will be a draw back when it comes to load balancing? Just
wanted
> clarify :-)
>
> Senthoor
>
> -----Original Message-----
> From: A mailing list for Enterprise JavaBeans development
> [mailto:[EMAIL PROTECTED]]On Behalf Of Krishnan Subramanian
> Sent: Wednesday, September 12, 2001 8:41 PM
> To: [EMAIL PROTECTED]
> Subject: Re: IntialContext
>
>
> Avi,
>
> They would be - if an instance of X "used" an
> instance of Y i.e. if you called
> instanceOfY.anotherMethod() from within your
> session bean X's someMethod, then both
> c1 and c2 will lookup the same definitions
> under "java:comp/env" defined in X's descriptor.
>
> In other words - for a particular process
> (or VM), an initial context instance is
> [re]usable by all beans (and normal java objects
> in turn referenced by those beans).
>
> You are right that a "java:comp/env" namespace
> is 'private' to that bean - and not available
> to other beans and I am not trying to debate that
> point. See above for debatable point ;)
>
> The point is moot if subsequent initializing of
> the context is optimized by the vendor (lightweight).
> Else, you might see performance improvements by caching
> that one instance within the VM.
>
> http://archives.java.sun.com/cgi-bin/wa?A2=ind0105&L=ejb-interest&P=R19960
>
> -krish
>
> >
> > I think what the original poster asked is, given the following code
> sequence
> >
> > public class X implements SessionBean {
> >
> > public void someMethod() {
> > Context c1 = new InitialContext();
> > }
> >
> > // ...
> >
> > }
> >
> > public class Y {
> >
> > public void anotherMethod() {
> > Context c2 = new InitialContext();
> > }
> >
> > }
> >
> > are c1 and c2 logically identical? This is a vendor-independent
question,
> > and the vendor-independent answer is no, c1 is not equivalent to c2,
> because
> > of the java:comp/env namespace. This has nothing to do with vendor
> > optimizations AFAICT.
> >
> > - Avi
>
>
===========================================================================
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
> of the message "signoff EJB-INTEREST". For general help, send email to
> [EMAIL PROTECTED] and include in the body of the message "help".
>
>
===========================================================================
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the
body
> of the message "signoff EJB-INTEREST". For general help, send email to
> [EMAIL PROTECTED] and include in the body of the message "help".
>
>
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.240 / Virus Database: 116 - Release Date: 3/23/2001
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.240 / Virus Database: 116 - Release Date: 3/23/2001
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
