Efficient Bulk Updates on Multiversion B-trees

Partial persistent index structures support efficient access to current and past versions of objects, while updates are allowed on the current version. The Multiversion B-Tree (MVBT) represents a partially persistent index-structure with both, asymptotic worst-case performance and excellent performance in real life applications. Updates are performed tuple-by-tuple with the same asymptotic performance as for standard Btrees. To the best of our knowledge, there is no efficient algorithm for bulk loading and bulk update of MVBT and other partially persistent index structures. In this paper, we propose the first loading algorithm for MVBT that meets the lower-bound of external sorting. In addition, our approach is also applicable to bulk updates. This is achieved by combining two basic technologies, weight balancing and buffer tree. Our extensive set of experiments confirm the theoretical findings: Our loading algorithm runs considerably faster than performing updates tuple-by-tuple.