Entity Bean Explosion?

[idxp]

The project I am handling has the following features:

1. Quite a lot(hundreds of thousand) entity beans will be created
2. And they will NEVER be removed

The project is to enhance a legacy project which used JDBC directly to persist data.

I also understand that EJB will be passivated and be put into the pool so that App Server will not be out of memory.

The question is that, even if an EJB is passivated, will it still occupy some resources on App Server? If yes, what kind of resource is occupied? If there are several million EJBs created and then passivated, will they exhaust resources of App Server since they will never be removed?

In the legacy system, this is not the problem. Because it used JDBC, all data only exists in DB, not App Server. I am going to enhance it using EJB. But due to the above considerations, I am hesitating whether to use it or not since it may require a huge amount resource to be added to App Server. (BTW, I am using JBOSS as App Server)

Any suggestions?

[darranl]

The long term persistence mechanism for the application server will still be to a database.

The in memory instances of the data will just be recently used entities in a cache.

The pasivation of beans has nothing to do with the long term storage of your data.

Have a look at http://www.theserverside.com/books/wiley/masteringEJB/index.tss

[idxp]

Suppose
cache size is 1000
pool size is 1000

how about if I created 5000 eneity beans.

the cache & pool will be both full. Where are the remaining 3000 active beans? Are they so-called long term persisted?

[darranl]

Are you really looking at adding 5000 entities in a single transaction?

[grzegorzgłowaty]

Sometimes it's really needed. Imagine import operation with some bussiness logic, where atomicity of a whole import is needed.

Please take a look at my case http://www.jboss.org/index.html?module=bb&op=viewtopic&t=47221. I still don't know if there's a bug (some kind of memory leak in JBoss) or if I do sth wrong.