Sorry, didn't get to to line right on this message, and it only went to
marc... read below...
-dain
----- Original Message -----
From: "Dain Sundstrom" <[EMAIL PROTECTED]>
To: "marc fleury" <[EMAIL PROTECTED]>
Sent: Tuesday, June 26, 2001 2:24 PM
Subject: Re: [JBoss-dev] Shouldn't expose transaction-isolation within CMP
> > |Please correct me if I'm wrong(I seem to be wrong about 50% of the
> > |time :-),
> > |but, I really don't think you should expose transaction-isolation
levels
> > |within CMP or in the definition of entities. This really belongs in
the
> > |creation of the connection pool. CMP cannot really guarantee that a
> > |connection will not be shared between different entity types
> > |within the same
> > |transaction that use the same connection pool. Actually, I'm pretty
sure
> >
> > which is why I am asking if the jdbc drivers support reconfiguration of
> the
> > isolation level on the fly or is it pretty much a "constructor" thingy.
> >
> > btw if it is the good case (we can change it) then it is not up to
minerva
> > to do this, all minerva does is hand out the connection but it is up to
a
> > functional unit above it, one aware of the application accessing this
> > connection. That would live in JCA, but it would need to know the
> > applciation context, or it would purely live in the app server sphere
> (i.e.
> > jaws getting the connection, or asking the container to do it on its
> behalf,
> > whatever we can do that call somewhere, factored or not).
> >
> > am i making sense?
> >
>
> I think I understand now. Here is some text I found the J2EE tutorial:
>
> ------------
> You cannot modify the isolation level of a entity beans with
> container-managed persistence. These beans use the default isolation level
> of the DBMS, which is usually READ_COMMITTED. For entity beans with
> bean-managed persistence and for all session beans, you can set the
> isolation level programmatically with the API provided by the underlying
> DBMS. A DBMS, for example, might allow you to permit uncommitted reads by
> invoking the setTransactionIsolation method:
>
> Connection con;
> ...
> con.setTransactionIsolation(TRANSACTION_READ_UNCOMMITTED);
>
> Do not change the isolation level in the middle of a transaction. Usually,
> such a change causes the DBMS software to issue an implicit commit.
Because
> the isolation levels offered by DBMS vendors may vary, you should check
the
> DBMS documentation for more information.
> -----------
>
> So the code I added probably causes an "implicit commit," which is bad.
> From my very JDBC centric perspective, this should be set in Minerva
> (JBossPool?) and user configurable. I don't know much about the connector
> architecture, so maybe Minerva is the wrong place.
>
> Any way, I think I should roll back my change. If you agree marc, just say
> so and it is done.
>
> I don't know any thing about Minerva, so if you want that changed, someone
> else would be better suited. If no one wants to do it, I'll look at it.
>
> -dain
>
_______________________________________________
Jboss-development mailing list
[EMAIL PROTECTED]
http://lists.sourceforge.net/lists/listinfo/jboss-development
