python2-larch 1.20151025 Python copy-on-write B-tree library
python2-larch is an implementation of particular kind of B-tree, based on research by Ohad Rodeh. See http://liw.fi/larch/ohad-btrees-shadowing-clones.pdf for details on the data structure.
The distinctive feature of this B-tree is that a node is never (conceptually) modified. Instead, all updates are done by copy-on-write. This makes it easy to clone a tree, and modify only the clone, while other processes access the original tree.