Hybride Indexstrukturen

Im Folgenden wird ein Promotionsprojekt zur Implementierung und Optimierung von hybriden Indexstrukturen beschrieben. Die erhöhte Suchperformance wird bei hybriden Indexstrukturen durch einen höheren Aufwand an Vorberechnungen bei Einfügeoperationen erreicht. Dadurch ergibt sich, im Gegensatz zu Ansätzen, welche mehrere Indexstrukturen miteinander verbinden oder getrennte Suchanfragen ausführen eine Effizienz der Reorganisation hybrider Indexstrukturen, die prohibitiv für den Einsatz in den meisten Anwendungen ist. Diese sollen innerhalb des Promotionsprojekts optimiert werden, um eine Einsatzfähigkeit in realistischen Szenarien gewährleisten zu können

Efficient Reorganisation of Hybrid Index Structures Supporting Multimedia Search Criteria

This thesis describes the development and setup of hybrid index structures. They are access methods for retrieval techniques in hybrid data spaces which are formed by one or more relational or normalised columns in conjunction with one non-relational or non-normalised column. Examples for these hybrid data spaces are, among others, textual data combined with geographical ones or data from enterprise content management systems. However, all non-relational data types may be stored as well as image feature vectors or comparable types. Hybrid index structures are known to function efficiently regarding retrieval operations. Unfortunately, little information is available about reorganisation operations which insert or update the row tuples. The fundamental research is mainly executed in simulation based environments. This work is written ensuing from a previous thesis that implements hybrid access structures in realistic database surroundings. During this implementation it has become obvious that retrieval works efficiently. Yet, the restructuring approaches require too much effort to be set up, e.g., in web search engine environments where several thousands of documents are inserted or modified every day. These search engines rely on relational database systems as storage backends. Hence, the setup of these access methods for hybrid data spaces is required in real world database management systems. This thesis tries to apply a systematic approach for the optimisation of the rearrangement algorithms inside realistic scenarios. Thus, a measurement and evaluation scheme is created which is repeatedly deployed to an evolving state and a model of hybrid index structures in order to optimise the regrouping algorithms to make a setup of hybrid index structures in real world information systems possible. Thus, a set of input corpora is selected which is applied to the test suite as well as an evaluation scheme. To sum up, it can be said that this thesis describes input sets, a test suite including an evaluation scheme as well as optimisation iterations on reorganisation algorithms reflecting a theoretical model framework to provide efficient reorganisations of hybrid index structures supporting multimedia search criteria