Andrig Miller [http://community.jboss.org/people/andy.miller%40jboss.com] replied to the discussion "Multiple Persistence Units with the same entities" To view the discussion, visit: http://community.jboss.org/message/536638#536638 -------------------------------------------------------------- Well, I don't use the same entities from two different entity manager's at the same time, or within the same transaction.  One entity manager is used to do an initial data load of a bunch of reference data into the database, and the other entity manager is used for transaction processing against that data.  The two processes are independent, and the OLTP processing cannot occur until after the batch process has completed anyway.  So, there is no overlap, where the same entity would be used in two entity managers at the same time, and have different state. Before even doing this, I thought through that, but is this something that is compliant with the spec.  All the reading I have done, only vaguely hint at having the same entities into two different persistence units, and everything I have read basically says that a persistence unit is tied to one data source (maybe implying that multiple persistence units should have "unique" data sources). So, while it works now, and based on the functions involved, there is no overlap, will this continue to work in the future?  If its not supported by the spec, then I have a reasonable expectation that this might break in the future. -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/536638#536638] Start a new discussion in EJB 3.0 at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]