eference counter field has short type. It means that PHP is not able to correctly
handle objects which are referenced from more than 65535 places. As far as each persistent
object contains reference to the storage object, this limitation means that there can not be more
than 65535 persistent object loaded from the database to the memory at each moment of time. 
You have to periodically invoke <code>Storage.resetHash</code> method to remove
persistent objects from the cache. Violation of this rule cause unpr