Toby Dickenson writes:

... problems with high frequency writes ... As I understand it, a BTreeFolder alone (ie without application-level conflict handling) will not help here.

Folders have to ensure that all their contained elements have a different id. The hot-spot is the only way a Folder can achieve this. Because the application specifies the id, all the folder has to do is verify that the id does not yet exist. This may "look" a path from root to leaf.

A conflict between two concurrent transactions results only, if either both want to modify the same leaf node or if a tree restructuring becomes necessary. Dieter