portability wins against speed if you need to make the tradeoff. indeed, a db compatibility layer could handle that. try to look into how people can customize the queries. can they customize the queries in the simulation queries hbm file ? meaning; is the API that we have to use to execute those queries the same for HQL as for native SQL queries ? if we can work out a solution like that, we can provide portable configuration file with HQL queries (perhaps slow, but portable) then people should be able to configure for their database a faster native SQL. but then their on their own. we could devote a wiki page where people could exchange their experiences. but i expect that the hibernate API will not be exactly the same. so that needs to be figured out. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4106295#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...