title: DB4O performance retrieving a large number of objects
body: <p>I'm interesting in using DB4O to store the training data for a learning algorithm.  This will consist of (potentially) hundreds of millions of objects.  Each object is on average 2k in size based on my benchmarking.</p>
  
  <p>The training algorithm needs to iterate over the entire set of objects repeatedly (perhaps 10 times).  It doesn't care what order the objects are in.</p>
  
  <p>My question is this:  When I retrieve a very large set of objects from DB4O, are they all loaded into memory, or are they pulled off disk as needed?</p>
  
  <p>Clearly, pulling hundreds of millions of 2k objects into memory won't be practical on the type of servers I'm working with (they hvae about 19GB of RAM).</p>
  
  <p>Is Db4o a wise choice here?</p>