This package provides support for a view of a local B+-Tree comprised of one or more source B+-Tree instances. The first component of the view is always a mutable {@link com.bigdata.btree.BTree} used to absorb writes for the view (read-only views use a read-only instance of that BTree). The sources in the view are ordered. Reads read against the sources in order, stopping on the first source for which their is a hit for a tuple. Writes are always directed to the first source in the view.

Fused views are the basic building block for index partitions. Each index partition consists of a mutable B+-Tree on the live journal and zero or more {@link com.bigdata.btree.IndexSegment}s having historical data for the same view.