Generating Persistence Mapping From Database Schema

I was recently instructed on how to use the new Hibernate facet to generate objects and mappings from database schemas. Very timely, since I'm working on a project with a group that wants to use Middlegen to accomplish this. I thought I'd try out IntelliJ's capabilities first.

I immediately ran into problems. The schema consists of 48 tables, some of which are rather large (~50 columns). I have a machine with 4GB RAM, and I sent up IntelliJ to have 075GB max RAM and 128MB perm space. In spite of this, my machine seemed to go off and not come back. Without experience, I have no idea if the CPU is making good progress and I just need to be more patient.

I've been experimenting this weekend with a schema that's much smaller (~10 tables, max of ~10 columns in the largest one), and the generation takes less than a minute.

Does anyone have any experience with using the Hibernate facet successfully to generate mappings and objects? I'd love to have a benchmark to see if I'm on the right track. Thanks.