How embarrasing! I should probably stay away from the computer at 6am. Everybody
else is right and I'm wrong. The good news is that our EJB server implements
options A, B and C.
Nevertheless for the original problem entity beans don't seem to be the right
approach.
Have a good week-end,
Andreas
Have a good week-end.
Imre Kifor wrote:
> Andreas,
>
> The spec does not require mandatory passivation of bean instances at the end
> of transactions. As a matter of fact, the spec describes three different
> commit options. Option A (page 122, EJB 1.1) describes the exact scenario
> you are prohibiting. Using CMP or implementing BMP, of course, doesn't have
> anything to do with the above.
>
> Imre Kifor
> Valto Systems
>
> -----Original Message-----
> From: Andreas Vogel <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Date: Friday, May 14, 1999 9:09 AM
> Subject: Re: EJBs and the internet
>
> >Robert,
> >
> >you need to look carefully at the life cycle definition for entity beans.
> An entity
> >in the pool is not associated with any data. The association happens at the
> begin of
> >a transaction, that is ejbLoad(), at the end of the transaction the data is
> written
> >back into persistence storage (ejbStore()), the entity returns to the pool
> and looses
> >the association with the data. The next client goes through the same cycle.
> The
> >advantage of the approach is data integrity, the disadvantages is
> performance
> >overhead. A container may do clever things when CMP is used.
> >
> >Cheers,
> >
> >Andreas
> >
> >Robert Krueger wrote:
> >
> >> Andreas Vogel wrote:
> >>
> >> >
> >> > Entity beans are specifically targeted towards transactions. Caching is
> a value
> >> > add of CMP implementation BMP prevents you from caching.
> >> >
> >>
> >> Why would that be? I thought a container could keep entity bean data in
> >> memory no matter if CMP or BMP? My understanding was that say client 1
> >> requests an entity bean instance with PK x which is not in main memory.
> >> It is retrieved from the DBMS (CMP or BMP) and instantiated in main
> >> memory. Then client 2 also requests the entity with PK x, which then may
> >> still be in main memory. Where is the difference between CMP or BMP
> >> here? It may very well be that I'm misunderstanding the spec as I am not
> >> an expert. Could you please enlighten my on that point as it seems to be
> >> a very important factor in designing an EJB application using entity
> >> beans with BMP with acceptable performance.
> >>
> >> Thanks,
> >>
> >> Robert
> >>
> >> --
> >> (-) Robert Kr�ger
> >> (-) SIGNAL 7 Gesellschaft f�r Informationstechnologie mbH
> >> (-) Br�der-Knau�-Str. 79 - 64285 Darmstadt,
> >> (-) Tel: 06151 665401, Fax: 06151 665373
> >> (-) [EMAIL PROTECTED], www.signal7.de
> >>
> >>
> ===========================================================================
> >> To unsubscribe, send email to [EMAIL PROTECTED] and include in the
> body
> >> of the message "signoff EJB-INTEREST". For general help, send email to
> >> [EMAIL PROTECTED] and include in the body of the message "help".
> >
> >--
> >"Programming with Enterprise JavaBeans, JTS and OTS" is now available.
> Collect all
> >three!
> >www.wiley.com/compbooks/vogel
> >
> >
>
> ===========================================================================
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
> of the message "signoff EJB-INTEREST". For general help, send email to
> [EMAIL PROTECTED] and include in the body of the message "help".
--
"Programming with Enterprise JavaBeans, JTS and OTS" is now available. Collect
all three!
www.wiley.com/compbooks/vogel
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
