Integrating the UB-Tree into a Database System Kernel Frank Ramsak1, Volker Markl1, Robert Fenk1, Martin Zirkel2, Klaus Elhardt3, Rudolf Bayer1,2 1Bayerisches Forschungszentrum 2Institut für Informatik 3TransAction Software GmbH für Wissensbasierte Systeme TU München Gustav-Heinemann-Ring 109, Orleansstraße 34, Orleansstraße 34, D-81739 München, Germany D- 81667 München, Germany D-81667 München, Germany {frank.ramsak, robert.fenk, volker.markl}@forwiss.de, {zirkel, bayer}@in.tum.de,
[email protected] Abstract Multidimensional access methods have shown 1 Introduction high potential for significant performance im- Various research approaches in the past have shown that provements in various application domains. multidimensional access methods (MAMs) have a high However, only few approaches have made their impact on different database application domains like data way into commercial products. In commercial warehousing, data mining, or geographical information database management systems (DBMSs) the B- systems. However, despite the vast research effort MAMs Tree is still the prevalent indexing technique. have not made their way into commercial database Integrating new indexing methods into existing management systems on a broad scale. This is mostly due database kernels is in general a very complex to the fact that the integration of these complex data and costly task. Exceptions exist, as our experi- structures into an existing database kernel is fairly ence of integrating the UB-Tree into TransBase, complicated. Especially concurrency and recovery issues, a commercial DBMS, shows. The UB-Tree is a which are as important as performance issues for very promising multidimensional index, which commercial systems, are major obstacles. For most has shown its superiority over traditional access MAMs new solutions to these problems, e.g., locking for methods in different scenarios, especially in R-Trees [KB95, CM98], have to be developed, as the new OLAP applications.