http://db4o.blogspot.com/2006/11/need-for-speed-db4o-tops-my.html
"I chose db4o as database-technology
and this was the best choice (besides Echo2) I could have made for this
project regarding the performance: my database-queries return in a few
milliseconds, so updates of the GUI are almost instantly. Working with
the application is now almost fun (besides the work to be done),
because no-one has to wait for anything anymore... thanks to Echo2 and
db4o."
Maik Jablonski