Unbalanced multiway trees improved by partial expansions

Abstract

Unbalanced multiway trees are generally impractical external data structures because of their poor space performance. In order to avoid this handicap, we have adapted the technique of partial expansions to these trees. Compared to partially expandedB+-trees in terms of average performance, the method proposed is faster, has more compact indexes, and shows the same almostoptimal asymptotic space performance at the data bucket level.