Re: Q: Multiple EJB servers with one DB

[Fong Shing Lam]

This is my question too. Say, if I have a news database that is updated by third party, and want to have a group of entity beans that serve news. In this entity bean class, I would intend to implement only the ejbLoad() method and some bussiness get methods for the session bean which will do whatever it needs with the returned news. For data integrity, I can only rely on a smart container which will get the table modify time frequent enough to invoke my ejbLoad(). This frequency is better configurable to suite my application need. Is this a feature for a general EJB server? or some other smart way to keep the memory in sycn with the underlying DB? Lam Javier Borrajo wrote:   Assume there's one (huge) DB to which we want to provide access through EJB.Assume that there're multiple EJB servers that should provide access to this DB.Assume that a row in the DB is represented by an entity bean.Now, if an entity bean has been instantiated at BOTH servers, and then updated from one server, how is the second bean (at the 2nd server) updated? (This is even more problematic if caching is used) I understand second bean only needs to be updated when involved in next transaction,so there is no integrity problem but yes a performance problem. Data caching is only possible/recommended if the EJB server does not sharethe database with any other system, other EJB servers included, unless the vendorimplements multiple node data caching mechanisms. Regards     Javier Borrajo    www.tid.es