Karl;
Most of the EJB containers I have tried out have multiple instances of a JVM
running, thats an awful lot of overhead. We are also running applications
where there are up to (and sometimes more) than 100 simultaneous accesses on
a bean. Even using clustering there is still an awful load on our cpu's at
that rate.
unless there is some way to access the bean other than through the
home/remote interface I cant think of any instance where a EJB is not
accessed remotely. Whether that RMI call is made locally or from a turly
remote client (application, applet, what have you) its still an RMI call. i
will grant that it will be faster on a local call than on a network call,
but it is still an RMI call. (I'll even grant that RMI is faster than Corba
IIOP, but I wonder, since the last tests I saw were using straight RMI if
that is even true now.)
I disagree on the changing databases using BMP. Enterprise level databases
all are pretty much standardized on SQl, and as long as you dont use some
database specific code to do your stuff in (whether that be calling stored
procedures or whatever) you should be able to be portable accross databses
using JNDI to get a datasource. I do agree there are not that many cases
where BMP is truly necessary however. :)
Al
----- Original Message -----
From: "Karl Avedal" <[EMAIL PROTECTED]>
To: "Al Fogleson" <[EMAIL PROTECTED]>
Cc: "Orion-Interest" <[EMAIL PROTECTED]>
Sent: Sunday, May 28, 2000 5:01 AM
Subject: Re: How are database JOINS achieved with EJBs?
> Hello Al,
>
> Al Fogleson wrote:
>
> > Yes and no. There is a terribly large amount of overhead involved in
> EJB to begin with
>
> Which overhead are you referreing to by this? The overhead involved
> should be low compared to the optimizations that are done to speed up
> data access.
>
> > then you start adding all the RMI calls over the network and that adds
> some load too
>
> Well, EJBs will not always be called remotely to start with. A very
> common scenario is that you write Servlets/JSPs that communicate with
> EJBs. Usually you will run your Web components and EJBs on the same
> servr and no RMI calls will be made. Of course though, if you need the
> remote access it will be used. But that is an overhead you need no
> matter what technology. Orion's RMI-transport protocol is very
> optimized.
> >There are some situations, especially when doing the kinds of things
> you are talking
> >about where BMP is the only way to go. Because of complex joins or the
> need for a
> >complex primary key. it does put more work on the bean developer but in
> some cases
> >it may be the only way to go.
>
> Yes, in a few very rare cases you need BMP because of the full control,
> but whenever you do, stop and think about wether you really need it. In
> most cases when BMP is used it's not really necesseary. And with BMP, as
> always, you won't get the performance of CMP and it won't be as simple
> to change database.
>
> Regards,
> Karl Avedal
>
