Omega Omega -storage : a self organizing multi-attribute storage technique for very large main memories

Main memory is continuously improving both in price and capacity. With this comes new storage problems as well as new directions of usage. Just before the millennium, several main memory database systems are becoming commercially available. The hot areas include boosting the performance of web-enabled systems, such as search-engines, and auctioning systems. We present a novel data storage structure -- the {em $Omega$-storage structure, a high performance data structure, allowing automatically indexed storage of {em very large amounts of multi-attribute data. The experiments show excellent performance for point retrieval, and highly efficient pruning for {em pattern searches. It provides the balanced storage previously achieved by random kd-trees, but avoids their increased pattern match search times, by an effective assignment bits of attributes. Moreover, it avoids the sensitivity of the kd-tree to insert orders

A Robust Scheme for Multilevel Extendible Hashing

Dynamic hashing, while surpassing other access methods for uniformly distributed data, usually performs badly for non-uniformly distributed data. We propose a robust scheme for multi-level extendible hashing allowing efficient processing of skewed data as well as uniformly distributed data. In order to test our access method we implemented it and compared it to several existing hashing schemes. The results of the experimental evaluation demonstrate the superiority of our approach in both index size and performance

Analysis and Comparison of Extendible Hashing and B+ Trees Access Methods

This thesis Is a discussion and evaluation of both extendible hashing and B+ tree. The study Includes a design and lmplementatlon under the UNIX system. Comparisons and analysis are made using empirical results.Computing and Information Scienc

Teknillinen korkeakoulu toimintakertomus 1981-1982

Sisältää tietoja mm. opettajista, opiskelijoista, opiskelijoiden määristä, suoritetuista tutkinnoista, harjoitteluista, myönnetyistä stipendeistä ja apurahoista sekä lahjoituksista