Hibernate version:
2.1.6

We are planning to use Hibernate/JBoss in our new project. If we want to use JBoss clustering feature for fail-safe, how does JBoss handle the Hibernate cache??? Does it try to synchronize the HibernateCache on all the clusters? If yes, won't it be a performance hit?

I'm quite new to JBoss/Hibernate and any input on this is greatly appreciated.

I just came across HAR and i'm yet to read about that. I'm planning to do it this weekend.

Use the JBossTree cache as the second level cache. Read JBoss web site for further (detailed) information.

Thanks David. I'll read the documentation for TreeCache.

If i want to use JBoss/Spring/Hibernate so that spring can manage Hibernate sessions/transactions, can i still use TreeCache?

Thanks again!

I don't use Spring in my work but many do and there should be no reason for it not to work. This is one of those - try and see - situations.

Thanks David. I just read the documentation for JBoss TreeCache and TreeCacheAOP. I think TreeCacheAOP makes more sense to me as i want the Cache to handle the inheritence hierarchy of my POJOs.

Now i understand that in the hibernate mapping files, to plug the TreeCacheAOP, i need to configure the cache_provider as TreeCacheAOP and set the related attributes and do putObject to add the class to be managed.

One question i've is (may be it's too weird), why Hibernate cache is called second-level cache (it's a cache on top of the datastore and that's the purpose of any cache)? what's different here and why the name SECOND?


Also, do i need to do this for all classes (POJOs)?

Where should i write the code putObject??? Say for example i've class A which is a POJO. For this, i'll have a DAO as ADao. I'll provide a Facade interface say MyProjImpl so that the client can call my business interface. Here, where should i write the code putObject to add my POJO to the cache?

Could you please let me know or point to any references?

Thanks!

If an external application directly modified the datastore, the hibernate cache becomes invalid. In this case, how will hibernate detect this change to the datastore? how should i handle this case? Any event notifications?

Could some one provide some insight on this?

Thanks!

There is not much free documentation from us about these things at the moment (a very generic, not necessarily Hibernate-only topic). Hibernate in Action has a chapter about transactions and caching.

One other thing is, if we try to replicate the Hibernate cache (even using JBossTreeCacheAOP) won't there be performance overhead?

Could some one provide some input on using TreeCacheAOP on clustered environment?

Thanks!

I'm not sure JBoss Cache AOP is in a final stage, the right place to ask is the JBoss-* forum we have here or at www.jboss.org, where Bela and Ben will read it. We will merge forums sooner or later. :)

Thanks Christian.

How about SwarmCache? You refered it in Hibernate in Action book. I've not read about SWarmCache yet. (I've too many things to read :) ) Is it a potential alternative for TreeCacheAOP? Is it the so-called "Object-oriented" cache which can manage inheritence hierarchy of POJOs?

Any other alternatives? I'll also check in the JBoss forum.

Thanks!

Normal JBoss Cache (without AOP replication).

But normal JBoss TreeCache doesn't support object-oriented caching for POJOs?? do i need to explicitly handle that?

Thanks!

I don't understand the term "object-oriented" in this context... the JBoss Cache AOP variation can replicate fine-grained changes instead of bigger update packages, for speed improvements in (I think) many situations. Your best bet for now may be the documentation of both and a quick look at the tutorials, all on www.jboss.org.

Sorry for the late reply.

Here's the excerpts from JBoss TreeCacheAOP documentation page



Thanks!

I am especially interested in this question. I read the Hibernate in Action, I didn't find answer to this question.

So, what if the database is chanaged outside Hibernate, the second level cache becomes invalid. Is there a way I can clean up the memory cache without restarting the whole application? I tried new Configuration().configure(file).buildSessionFactory(), but it doens't work.

Any idea about this question? I think this is a very common situation. Whenever people run into problem of caching, they should be able to clear the memory caching without restarint application.

Thanks.