Hi Dominic:
I have three questions:
1. What happens if the underlying database is modified via some other
application (since Option B doesn't assume exclusive access to the
underlying database)? How is the application server notified? Does your
design require that special triggers be added to the database?
2. Does this design require that the app server implement transactions,
including isolation levels, at the app server level?
3. Does this solution assume CMP? In BMP, the ejbLoad() and ejbStore()
methods would access/update the database directly using JDBC (and thus
by-pass your cached state). Or does FrontierSuite do something tricky with
the data sources and connections?
Is FrontierSuite a product used by app server vendors, or a product app
server users purchase as an add-on to their app server?
Thanks.
Laurel
-----Original Message-----
From: Dominic Savio [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, July 25, 2001 8:24 PM
To: [EMAIL PROTECTED]
Subject: Re: locking Entity Beans
Yes Evan,
Option B will be the choice for scalable solution. As you have mentioned
about caching with option B, underlying architecture in the application
server can maintain the cached state (state object)of the bean separately
and all the concurrent beans can load (through ejbLoad) from the state
object rather than from the database.
The issue comes when one of the client has modified the bean and committed
the changes. In that case the state object of the bean should be updated so
that the new clients can get the newly commited state of the bean from the
cache.
Note that FrontierSuite from ObjectFrontier provides such a runtime solution
for all application servers in a portable way.
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