[Zope] ZODB performance: reads to writes

[Dieter Maurer]

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