http://dl.gi.de/handle/20.500.12116/11561 Thu, 23 Jul 2026 10:49:14 GMT 2026-07-23T10:49:14Z http://dl.gi.de/handle/20.500.12116/11615 „Von der Torfabrik zur Denkfabrik“ Bericht zur 14. Fachtagung „Datenbanksysteme für Business, Technologie und Web“ Bächle, Sebastian; Härder, Theo; Höfner, Volker; Klein, Joachim; Ou, Yi; Reithermann, Steffen; Schall, Daniel; Schmidt, Karsten; Weiner, Andreas Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/11615 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/11618 Multidimensional Expressions (MDX) Kempa, Martin Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/11618 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/11619 Integrating Cluster-Based Main-Memory Accelerators in Relational Data Warehouse Systems Stolze, Knut; Beier, Felix; Koeth, Oliver; Sattler, Kai-Uwe Today, data warehouse systems are faced with challenges for providing nearly realtime response times even for complex analytical queries on enormous data volumes. Highly scalable computing clusters in combination with parallel in-memory processing of compressed data are valuable techniques to address these challenges. In this paper, we give an overview on core techniques of the IBM Smart Analytics Optimizer—an accelerator engine for IBM’s mainframe database system DB2 for z/OS. We particularly discuss aspects of a seamless integration between the two worlds and describe techniques exploiting features of modern hardware such as parallel processing, cache utilization, and SIMD. We describe issues encountered during the development and evaluation of our system and outline current research activities for solving them. Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/11619 2011-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/11620 Sorting in a Memory Hierarchy with Flash Memory Graefe, Goetz Flash memory continues to improve in price, capacity, reliability, durability, and performance. In addition to consumer and client devices, flash memory is also employed in many servers. Its optimal usage in various classes of server software, including web servers, file-and-print servers, and database servers, requires evaluation and analysis. The present paper analyzes the use of flash memory for database query processing including algorithms that combine flash memory and traditional disk drives.External merge sort serves as a prototypical query execution algorithm. The excellent access latency of flash memory promises substantially better sort performance than sorting with traditional disks. Surprisingly, this is true only in fairly limited cases. Flash memory as intermediate external storage improves performance in particular in situations with very limited memory.The most advantageous external sort algorithms combine flash memory and traditional disk, exploiting the fast access latency of flash memory as well as the fast transfer bandwidth and inexpensive capacity of traditional disks. Moreover, graceful degradation is required in multiple ways, both when spilling from memory to flash storage and when spilling from flash to disk. These algorithms are described in detail, including in particular their graceful transition from run generation to merging. Using such graceful degradation and incremental transitions, sorting in a three-level memory hierarchy of RAM, flash memory, and traditional disk can be generalized to database query processing with any number of levels. Sat, 01 Jan 2011 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/11620 2011-01-01T00:00:00Z