| CACHE_TYPE_DEFAULT [message #383007] |
Wed, 05 November 2008 10:50  |
Eclipse User |
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I'm probably missing some documentation where this is mentioned, but it's probably a simple question.
I have two applications running, when I do a "refresh" I clear the entitymanager and refetch the entities. If the BM runs with:
cfg.put(PersistenceUnitProperties.CACHE_TYPE_DEFAULT, CacheType.NONE);
Then the changes is the database are visible in the refetched entities. However if the BM runs with:
cfg.put(PersistenceUnitProperties.CACHE_TYPE_DEFAULT, CacheType.Soft);
I can refresh until Christmans but the changes never shows up. A different EM in the same JVM will get the updated values and the change has been written back to the database.
If I use the CACHE_TYPE_* how do I really force to read stuff from the database?
Tom
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| Re: CACHE_TYPE_DEFAULT [message #383013 is a reply to message #383012] |
Mon, 10 November 2008 05:09  |
| Eclipse User |
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> clear() only clears the transactional cache, not the shared cache.
Understood.
> I would not recommend using CacheType.None, if you truly do not which to
> cache, you can use an isolated cache using the persistence.xml property
> "eclipselink.cache.shared.default"="false".
Ok. My application is a change-heavy application; orders are entered, articles get a different status, data is changed all the time. The users know that other users may also change data, but they really need to be certain that when a refresh is done, they really have the most current data. Caching is only ok during a session (that is: work done not inside a transaction). As soon as a transaction has run, and the changes have been committed, data needs to be refreshed.
I'm a bit amazed that the cache is this cachy; as in that one has to explicitly refresh stuff. This model seems to work for webapps (many EM but all running within one JVM) and not a simple 2 tier fat client (just a few EM per JVM but multiple JVMs).
Hmmm. Maybe I should consider a distributed cache. That would solve the "has been updated" issue.
> If you want to manually clear the shared cache use can get the
> EclipseLink Session (getServerSession()) from the EclipseLink
> JpaEntityManager, and get the IdentityMapAccessor
> (getIdentityMapAccessor()) from the Session. The IdentityMapAccessor
> contains API to clear and invalidate the cache. On a live system
> invalidation is safer than clearing, as the objects may be in use
> (initializeIdentityMaps(), invalidateAll()).
Thanks for the complete reply!
Tom
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| Re: CACHE_TYPE_DEFAULT [message #500957 is a reply to message #383015] |
Mon, 30 November 2009 08:18 |
| Eclipse User |
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Revisting the caching because I'm running into some performance issues during data entry in my Swing application.
Is it very strange that I expect entities to be cached within an EM, until the EM is cleared?
public static void main(String[] args)
{
System.out.println( "java.vm.version=" + System.getProperty("java.vm.version"));
com.informix.jdbc.Version.main(new String[]{});
// -------------
// entitymanagerfactory
Map<String, Object> lOptions = new HashMap<String, Object>();
lOptions.put(PersistenceUnitProperties.JDBC_DRIVER, ...);
lOptions.put(PersistenceUnitProperties.JDBC_URL, ...);
lOptions.put(PersistenceUnitProperties.JDBC_USER, "user");
lOptions.put(PersistenceUnitProperties.JDBC_PASSWORD, "user");
lOptions.put(PersistenceUnitProperties.TARGET_DATABASE, nl.reinders.jdbc.InformixPlatform.class.getName());
lOptions.put(PersistenceUnitProperties.TARGET_SERVER, TargetServer.None);
EntityManagerFactory lEntityManagerFactory = Persistence.createEntityManagerFactory("reinders", lOptions);
// entitymanager
EntityManager lEntityManager = lEntityManagerFactory.createEntityManager();
// test
lEntityManager.createQuery("select t from Relation t where t.iRelationnr=1").getSingleResult(); // expect: not cached
lEntityManager.createQuery("select t from Relation t where t.iRelationnr=1").getSingleResult(); // expect: cached
lEntityManager.clear();
lEntityManager.createQuery("select t from Relation t where t.iRelationnr=1").getSingleResult(); // expect: not cached
// close shop
lEntityManager.close();
lEntityManagerFactory.close();
}
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