Hi Armin
Thanks a lot, I'll modify all my DAOs ( what a job!!! ;-) ) and I'll try
again.
Yesterday I took another idea to improve:
Use a Singleton class that hold the cache, so in my DAOs I have just to
retrieve it without using a broker.
I explain with an example
I will have the private constructor of my singleton that is called
ServiceLocator:
Private ObjectCache cache;
private ServiceLocator() {
try{ ..........
broker=......
cache = broker.serviceObjectCache();
}catch...
finally{broker.close()}
}
public ObjectCache getCache(){return cache}
then in my DAO I still do:
cache= ServiceLocator().getInstance().getCache();
Identity oid = new Identity(parametroVO,broker);
parametroVO = (ParametroVO)cache.lookup(oid);
(ParametroVO extends ValueObject, that's why I cast to it directly)
could this work?
What about my cache in ServiceLocator when I close the broker?
If it will be still alive it will see changes (I refer DAOs putting
object in cache).
If it works it could have good performance?
Thanks for your help as always.
Ciao
-----Mensaje original-----
De: Armin Waibel [mailto:[EMAIL PROTECTED]
Enviado el: viernes, 17 de diciembre de 2004 1:07
Para: OJB Users List
Asunto: Re: RV: Cache and PersistenceBroker optimization
Hi Alessandro,
Alessandro Colantoni wrote:
> So opening a broker, look up for cache and closing the broker
shouldn't
> affect my performances.
>
yep, as Jean-Baptiste said PB only obtain a connection from pool when
it's needed.
> But I'm consuming a lot the Cpu oh the application server, and The DB
> server is sleeping
>
hmm, you can clean up your method doing
public ValueObject findByPrimaryKey(Integer parCodigo)
{
// handle try/catch/finally/broker.close
...
broker = ...
// assume you use a single PK and ParametroVO is the object
// real class, so I use best performing method to build an
// Identity object
Identity oid =
broker.serviceIdentity().buildIdentity(ParametroVO.class, parCodio);
// cast to ValueObject instead?
return (ParametroVO) broker.getObjectByIdentity(oid);
...
}
this does internal the same as you do and should show better
performance.
> An other point is that I don't use beginTransaction and commit
> transaction because I have just to retrieve data.
> Then what about the PersistenceBroker pool?
OJB uses to pools by default. One PB-pool and a connection-pool (default
ConnectionFactory class, except DataSource will never be pooled). The PB
instance was returned to pool on PB.close().
The PB instance obtain a connection from the ConnectionFactory when do
the query. You don't use PB-tx (that's ok when read data) the connection
was released on PB.close() call.
regards,
Armin
> Can I configure it in some way.
> Should it affect my performance if I do a very big use?
> thanks
>
> -----Mensaje original-----
> De: CLARAMONTE Jean-Baptiste [mailto:[EMAIL PROTECTED]
> Enviado el: jueves, 16 de diciembre de 2004 14:52
> Para: 'Alessandro Colantoni '
> Asunto: RE: Cache and PersistenceBroker optimization
>
> If I remember well a DB Connection is borrowed when you make a call to
> beginTransaction and gets back when you call commitTransaction or
> abortTransaction.
>
> PersistenceBrokerFactoryFactory.instance().defaultPersistenceBroker()
is
> borrowing an PersistenceBroker from the PersistenceBroker pool and
> broker.close puts it back
>
>
>
> -----Message d'origine-----
> De: Alessandro Colantoni
> A: 'OJB Users List'
> Date: 16/12/2004 14:27
> Objet: Cache and PersistenceBroker optimization
>
>
>
> -----Mensaje original-----
> De: Alessandro Colantoni [mailto:[EMAIL PROTECTED]
> Enviado el: jueves, 16 de diciembre de 2004 14:23
> Para: 'OJB Users List'
> Asunto: Cache and per
>
>
>
> Hi all!!
> I'm doing a very large use of caching.
> I have to do thousands of small queries that look for a small number
of
> entries.
>
> I'm using the connection pool of OC4J.
> The application consumes rapidly a large number of connections.
>
> I implemented the queries in DAOs that have methods like this one
>
>
> public ValueObject findByPrimaryKey(Integer parCodigo)throws
> DataAccessException{
> PersistenceBroker broker = null;
> ParametroVO parametroVO = null;
> try{
> broker =
> PersistenceBrokerFactoryFactory.instance().defaultPersistenceBroker();
> parametroVO = new ParametroVO();
> parametroVO.setParCodigo(parCodigo);
>
> Identity oid = new Identity(parametroVO,broker);
> ObjectCache cache = broker.serviceObjectCache();
> parametroVO = (ParametroVO)cache.lookup(oid);
> if (parametroVO==null){
> Criteria criteria = new Criteria();
> criteria.addEqualTo("parCodigo",parCodigo);
> Query query = new QueryByCriteria(ParametroVO.class,
> criteria);
> parametroVO =
> (ParametroVO)broker.getObjectByQuery(query);
> }else {
> log.info("************parametroVO in
> cache***************");
> }
> } catch (ServiceLocatorException e) {
> log.error("ServiceLocatorException thrown in
> ParametroDAO.findByPrimaryKey(Integer parCodigo): " + e.toString());
> throw new DataAccessException("Error in
> ParametroDAO.findByPrimaryKey(Integer parCodigo): " + e.toString(),e);
> } catch (ClassNotPersistenceCapableException e) {
> log.error("ClassNotPersistenceCapableException thrown in
> ParametroDAO.findByPrimaryKey(Integer parCodigo): " + e.toString());
> throw new DataAccessException("Error in
> ParametroDAO.findByPrimaryKey(Integer parCodigo): " + e.toString(),e);
> } finally {
> if (broker != null) broker.close();
> }
> return parametroVO;
> }
>
> My question is:
> The DB connection is opened when I do
> broker =
> PersistenceBrokerFactoryFactory.instance().defaultPersistenceBroker();
>
> and is released when I do broker.close()?;
>
> As I told, almost always the ValueObject is found in cache.
> Is there any way to check if it is in cache without opening a broker?
>
> I saw in documentation the constructor
> public Identity(java.lang.Class realClass,
> java.lang.Class topLevel,
> java.lang.Object[] pkValues)
>
> But I don't understand how to use it.
> What's the difference between realClass and topLevel?
> Does this constructor could be useful for me?
>
> Hoping someone can help me
> Thanks in advance
>
>
>
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