Hi,
Here are my settings in weblogic 6.0:
<trans-attribute>NotSupported</trans-attribute>
concurrency-strategy>ReadOnly</concurrency-strategy>
I would have taken your point if the 200 beans are in
the pool but the 200 beans I am saying is not the pool
size,it is the cached Beans specified by
<max-beans-in-cache>200</max-beans-in-cache>
And I believe that the cached entities are instances
associated with a primary key unlike the beans in the
pool!
Does this mean that weblogic has multiple instances
for the same primary key in the cache?
Is there any documention from weblogic which states
explains this?
Thanks for the help in advance.
Regards,
Ravi
--- Juan Pablo Lorandi <[EMAIL PROTECTED]> wrote:
> If you launch 200 concurrent TXs accessing the same
> entity with an
> isolation setting different from SERIALIZED, you're
> bound to get up to
> 200 entities.
>
> Think about what happens when two concurrent
> transactions want to access
> the same LOGICAL Entity Bean(that is, the same PK).
> There is a property
> of transactions called Isolation that states that
> changes being
> performed by a transaction aren't visible to any
> other transaction. The
> actual semantics of the operation are defined by the
> isolation level
> that you select for the transaction. Since there's
> plenty of
> documentation about these principles that apply to
> all Transaction
> Processing systems, I leave it to you to browse the
> web and your nearest
> library to find out more about it.
>
> However, I don't think that's the reason for the
> behavior you describe.
> Here's my take.
> Weblogic is configured for a pool of 200 Entity
> Beans. While they're on
> the pool they're unasigned, that is, they do not
> have a PK associated
> with each instance. I'll repeat that: while on the
> pool, the instances
> are in an undetermined state- they will be populated
> with data BEFORE
> they're passed on to a client, and when released by
> a client, they will
> be synched with the DB (commited) BEFORE entering
> the pool again.
>
> Wow, what a ramble... Gotta get some sleep.
>
> Juan Pablo Lorandi
> Chief Software Architect
> Code Foundry Ltd.
> [EMAIL PROTECTED]
>
> Barberstown, Straffan, Co. Kildare, Ireland.
> Tel: +353-1-6012050 Fax: +353-1-6012051
> Mobile: +353-86-2157900
> www.codefoundry.com
>
>
> > -----Original Message-----
> > From: ravi kakani [mailto:[EMAIL PROTECTED]]
> > Sent: Monday, April 22, 2002 8:30 PM
> > To: Juan Pablo Lorandi; [EMAIL PROTECTED]
> > Subject: Re: Reg number of instances per primary
> key?
> >
> >
> > Hi Juan,
> > Thanks for the reply.I am running a test
> with
> > only 100 records in the DB and the max cache size
> is
> > set to 200.Since there are only 100 records in the
> DB
> > shouldn't the weblogic be having only 100 beans
> > cached(ie one instance per the same primary key)?
> >
> > I am finding in the console that 200 beans are
> > cached!Does this mean that if there are more than
> one
> > concurrent transaction with the same entity and
> the cached
> > bean for particular primary key is being used by a
> client
> > then another instance of the bean with the same
> primary key
> > is created to serve another client? Does this mean
> that the
> > weblogic server has multiple instances for the
> same primary key?
> >
> > Regards,
> > Ravi
> >
> >
> > --- Juan Pablo Lorandi <[EMAIL PROTECTED]>
> wrote:
> > > I think he means with the SAME primary key. That
> > > depends on the server
> > > implementation, and the amount of concurrent
> TX's
> > > that interact with the
> > > SAME entity, the latter of course depends on the
> > > isolation level
> > > associated with the EB.
> > >
> > > That information is supposed to be concealed by
> the
> > > app server(for a
> > > number of reasons, mainly, scalability issues,
> and
> > > TX isolation). You
> > > should not care about it.
> > >
> > > The real question is: Why do you want to know?
> > >
> > > Remains curious,
> > >
> > > Juan Pablo Lorandi
> > > Chief Software Architect
> > > Code Foundry Ltd.
> > > [EMAIL PROTECTED]
> > >
> > > Barberstown, Straffan, Co. Kildare, Ireland.
> > > Tel: +353-1-6012050 Fax: +353-1-6012051
> > > Mobile: +353-86-2157900
> > > www.codefoundry.com
> > >
> > >
> > > > -----Original Message-----
> > > > From: A mailing list for Enterprise JavaBeans
> > > development
> > > > [mailto:[EMAIL PROTECTED]] On Behalf
> Of
> > > John Bateman
> > > > Sent: Monday, April 22, 2002 7:24 PM
> > > > To: [EMAIL PROTECTED]
> > > > Subject: Re: Reg number of instances per
> primary
> > > key?
> > > >
> > > >
> > > > Hi
> > > >
> > > > Aren't these number all dependant on the amout
> > > that the
> > > > initial pool size is set to?
> > > >
> > > >
> > > > > 1)How many instances of an entity bean(Read
> > > only)
> > > > > exist with a given primary key on a single
> > > server
> > > > > instance?
> > > >
> > > >
> > >
> >
>
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> > >
> > >
> >
>
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