Providing hinting about what objects are going to be needed, rather than how to pull them from the rdbms .... A perfect example of an optimization that would be tough to do by hand here is to stream elements in a collection down the join chain from the primary queried entities rather than pulling them in the initial join. In HSQL you would join them as you *know* you will need them, but what you really know is that the JSP needs them for rendering a while in the future, and on a different jvm. A mechanism to supply hints that these things will be needed, and will be needed as a one-pass stream (this may be too low level) when they get serialized out allows for much better actual throughput.