On Fri, 28 Jul 2000 13:24:38 +0100, Lahooti, Hamid
<[EMAIL PROTECTED]> wrote:
>>Agreed, although the multi-VM thing assumes that the VM's share data.
>The shared data is in the database. If you update a DB record in one VM,
>how do you ensure a different VM's cashed bean instance gets updated.
But I just said that the assumption that a multi-VM container shares
data between VM's may be incorrect. So, if they don't then there is no
need to ensure that a different VM's beans instance gets updated, simply
because there isn't one.
>>>2) The best place to cache instance data is probably the DBMS cache
>>Why?
>Because bean instance data represents information in the database which is
>can be cached by the DBMS.
I know that it *can* be cached in the DBMS. I wanted to know *why* the
DBMS is the *best* place to cache it in this scenario. IMHO sometimes
that is the case, and sometimes that is not the case. Saying that it is
The best place makes too many assumptions about the scenario at hand.
>>>3) You can always buy an ODBMS plugin for the container
>>I'm using RDBMS's most of the time.
>>Hmm.. make that always..
>I am talking about using ODBMS as a cache (see Javlin, Versant).
>You are talking about the backend datastore, different things.
I may not want to use an ODBMS. I may want to use an EJB container that
talks directly to the RDBMS.
>>Again, you are assuming that your view is the only correct one. I'm not
>>saying that PCC is "best", and I am not saying that OCC is "best".
>
>You said OCC was dumb. That's a generalisation for a whole class of
>application servers that use it.
No no no... I said that using {OCC in the EJB container+serializable
isolation level in the DB} for scenarios where pessimistic concurrency
control is needed is dumb, since it is not possible to cache the data.
"Dumb" was a bad choice of words though. "inappropriate" would be
better.
>>I would suggest that you try to get a wider perspective of these issues.
>You should practice what you preach.
:-) I do.
/Rickard
--
Rickard �berg
Email: [EMAIL PROTECTED]
http://www.telkel.com
http://www.jboss.org
http://www.dreambean.com
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