Is there any reason for handling NodeReferences in a different way that NodeStates and PropertyStates?.
NodeReferences simply contain a list of UUIDs that reference the corresponding Node. They are not cached in any layer of Jackrabbit. They are primarily used to determine when a node is no longer referenced by any REFERENCE property and can therefore safely be removed.
It seems this is an issue for PMs other than ObjectPM and XMLPM. It affects performance unnecessarily, especially when dealing with a big amount of references.
I wouldn't call it an issue. In the case of ORM PM you found out yourself that the problematic part was caused by a referential integrity test that was supposed to fail.
But you're right that for nodes being highly referenced, additions or removals are rather expensive. We should probably introduce a "modification-aware" NodeReferences object that is able to tell what references have been added or removed.
Regards Dominique
