Jim,
Our strategy is to partition persistent data into shared and private
sections. We disable caching on shared data and enable it on private data.
Most of the summary info used in collection beans is private and is
persisted to our instance store (which is local file based and really fast).
Imre
-----Original Message-----
From: Jim Frentress <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Friday, May 14, 1999 6:24 PM
Subject: Re: caching of beans was RE: EJBs and the internet
>WebLogic has the *option* to cache data if you set dbIsShared=false
>(default) in the deployment descriptor and follow a few other rules. Keep
in
>mind that if you cache, you must make all pstore modifications through the
>appserver (ie Ejipt, WebSphere or whatever).
>
>I personally think it would be a mistake to depend on this caching for
>anything except for performance.
>
>BTW: make sure to init your newly created beans before use if you don't
want
>random data coming from the pool (unless you know for sure your vendor
>doesn't have this problem). cache does have its downside.
>
>> -----Original Message-----
>> From: Sachin Aggarwal [SMTP:[EMAIL PROTECTED]]
>> Sent: Friday, May 14, 1999 2:45 PM
>> To: [EMAIL PROTECTED]
>> Subject: caching of beans was RE: EJBs and the internet
>>
>> Hmmm...
>>
>> We've bean counting on caching of the beans.
>>
>> Not just caching of the the instance in the pool so that a new instance
>> doesn't have to be created but caching of the state so a database
>> retrieval
>> doesn't have to be done every time.
>>
>> I'm very interested in knowing that which EJB Servers support this level
>> of
>> caching of the beans.
>>
>> Imre, since you pointed this scenario out, am I to assume Ejipt supports
>> this ?
>>
>> Anyone know about Weblogic ?
>>
>> Thanks,
>> Sachin.
>>
>> -----Original Message-----
>> From: A mailing list for Enterprise JavaBeans development
>> [mailto:[EMAIL PROTECTED]]On Behalf Of Imre Kifor
>> Sent: Friday, May 14, 1999 6:40 AM
>> To: [EMAIL PROTECTED]
>> Subject: Re: EJBs and the internet
>>
>>
>> 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
>> >>
>> >>
>>
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>> >
>> >--
>> >"Programming with Enterprise JavaBeans, JTS and OTS" is now available.
>> Collect all
>> >three!
>> >www.wiley.com/compbooks/vogel
>> >
>> >
>>
>>
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