Hi Aime,
We had a similar problem. It came down to long running
transactions (we had a connection pool) and how resultsets were
freed.

If we did
ResultSet rs = con.createStatement().executeQuery("select * from
employee");
...
rs.free();

Then the memory usage went through the roof. If we added
rs.getStatement.free() before the rs.free() the problem went away.

Regards
Ian Newby