Tobias,
EJB components are not allowed to fork or spawn threads -- the EJB server is
responsible for all operating system services, so it manages the
multithreading for you. This approach definitely aids in cross-system
portability, since you don't have to be aware of the underlying thread
package. The EJB server should be tuned to take advantage of
platform-specific features and optimizations. The EJB server also manages
resource pooling and recycling to make much better use of scarce and
expensive system resources. You're also bound to get better economies of
scale this way.
If you make your components small-enough-grained then you would have no
reason to spawn a new thread. If you need asynchronous processing for some
reason, use JMS.
As for entity beans and container-managed persistence -- there is no
requirement in the specification that states that entity beans map to
database rows. It's an implementation issue. Persistence PowerTier,
GemStone/J, Secant Extreme, and other implementations support much more
complex mappings. WebSphere is definitely not to best performing app server
on the market. (the next release due out in the next month or so should
bring WebSphere a little closer to par with the other products out there).
The above three implementations provide a shared object cache that allows
you to cache the data in memory. It dramatically reduces the number of I/Os
and offers much better data access performance.
Regards,
Anne
-----Original Message-----
From: Dezulian, Tobias [mailto:[EMAIL PROTECTED]]
Sent: Monday, May 31, 1999 5:41 AM
Subject: 2 questions
* as far as I understand the Spec there's no way for EJBs to fork()/spawn
new threads.
Isn't that a big deficit cause it prevents scaling ? What did I miss here
?
* entity beans map database rows.
In my experience ( WebSphere ) that's incredibly slow. Far too slow for
any serious application accessing a DB.
Any thoughts on that ?
Thanx a bunch, Tobias Dezulian
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