Hi,
hmmm, I need to consult more specs. I agree that the extra level of
pooling in a resource adapter seems excessive. In addition, the
XADataSourceImpl providing fake xa wrappers needs the kind of sharing you
describe. I have found in the JTA spec that the resource adapter is
required to accept the prepare/commit calls on any XAResource, not
necessarily one involved previously in the particular transaction. I don't
find any discussion of sharing whereby two connections are opened in one
transaction: is the pool supposed to supply the same connection or are
there requirements that it doesn't need to? If you come up with some specs
discussing this please let me know. I'll keep thinking.
Thanks
david jencks
On 2001.08.06 10:52:56 -0400 "Jung , Dr. Christoph" wrote:
> Hi David,
>
> -----Ursprüngliche Nachricht-----
> >Von: David Jencks [mailto:[EMAIL PROTECTED]]
> >Gesendet: Montag, 6. August 2001 15:12
> >An: [EMAIL PROTECTED]
> >Betreff: Re: [JBoss-dev] Anyone interested in a
> >org.jboss.pool.connector.SharedXAConnectio nManager?
>
> >Hi,
>
> >I'm not sure yet what I think about adding it to cvs. I have two
> comments.
>
> I´m also not sure whether the assumptions of our server environment are
> of
> general scope, hence my
> question ...
>
> >1. This would also be useful in case there is a "half-xa" driver that
> >supports 2pc but not sharing transactions accross connections.
> (natively,
> >firebird/interbase has supported 2pc since about 1984, but does not
> >currently share transactions across connections.)
>
> We are working on a resource adapter to the Business Sight Framework
> (http://www.objectmatter.com)
> that is currently indeed "half-xa". But getting the crucial "one-phase"
> option was just
> a minor reason for choosing that pooling scheme.
>
> >2. Did you write/do you have the source to the resource adapter? I think
> a
> >better approach is to map all requests on a given transaction to a
> single
> >connection/cache inside the resource adapter. This is what I did with
> the
> >firebird driver I am working on. Even if technically xa-compliant, not
> >sharing a transactional cache when work comes in on several
> >ManagedConnections is surely not in the spirit of all the xa connection
> >sharing.
>
> We´ve got the full source. Hence the managedconnection*-1connection would
> be
> possible ...
>
> But, otherwise, whats the use of the jbosspool, then, because as I
> understand you have to mirror much of the
> matching, mapping and pooling logic again in this second layer of
> connection
> sharing? Furthermore, I think that XA sharing also makes sense for other
> full-blown XA resources (what we want to reach with our adapter ASAP) ...
> But maybe this is just my perception ...
>
> CGJ
>
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