Auflistung nach:
Auflistung BTW - Datenbanksysteme für Business, Technologie und Web nach Titel
1 - 10 von 692
Treffer pro Seite
Sortieroptionen
- Textdokument1st Workshop on Novel Data Management Ideas on Heterogeneous (Co-)Processors (NoDMC)(BTW 2019 – Workshopband, 2019) Broneske, David; Habich, Dirk
- KonferenzbeitragAccelerating Large Table Scan using Processing-In-Memory Technology(BTW 2023, 2023) Baumstark, Alexander; Jibril, Muhammad Attahir; Sattler, Kai-UweToday’s systems are capable of storing large amounts of data in main memory. In-memoryDBMSs can benefit particularly from this development. However, the processing of the data fromthe main memory necessarily has to run via the CPU. This creates a bottleneck, which affects thepossible performance of the DBMS. The Processing-In-Memory (PIM) technology is a paradigm toovercome this problem, which was not available in commercial systems for a long time. However, withthe availability of UPMEM, a commercial system is finally available that provides PIM technologyin hardware. In this work, the main focus was on the optimization of the table scan, a fundamental,and memory-bound operation. Here a possible approach is shown, which can be used to optimizethis operation by using PIM. This method was then tested for parallelism and execution time inbenchmarks with different table sizes and compared to the usual table scan. The result is a table scanthat outperforms the scan on the usual CPU significantly.
- TextdokumentAn Actor Database System for Akka(BTW 2019 – Workshopband, 2019) Schmidl, Sebastian; Schneider, Frederic; Papenbrock, ThorstenSystem architectures for data-centric applications are commonly comprised of two tiers: An application tier and a data tier. The fact that these tiers do not typically share a common format for data is referred to as object-relational impedance mismatch. To mitigate this, we develop an actor database system that enables the implementation of application logic into the data storage runtime. The actor model also allows for easy distribution of both data and computation across multiple nodes in a cluster. More specifically, we propose the concept of domain actors that provide a type-safe, SQL-like interface to develop the actors of our database system and the concept of Functors to build queries retrieving data contained in multiple actor instances. Our experiments demonstrate the feasibility of encapsulating data into domain actors by evaluating their memory overhead and performance. We also discuss how our proposed actor database system framework solves some of the challenges that arise from the design of distributed databases such as data partitioning, failure handling, and concurrent query processing.
- KonferenzbeitragAdaptive Architectures for Robust Data Management Systems(BTW 2023, 2023) Bang, TiemoForm follows function is a well-known expression by the architect Sullivan asserting that the architecture of a building should follow its function. 'Adaptive Architectures for Robust Data Management Systems' is a dissertation asserting that DBMS architectures should follow changing workload and hardware to robustly achieve high DBMS performance. The dissertation first evaluates how workload and hardware affect the performance of DBMSs with static architectures. This evaluation concludes that static DBMS architectures degrade DBMS performance under changing workload and hardware, and hence the DBMS architecture has to become adaptive. Subsequently, adaptation concepts for the architecture of single-server and multi-server DBMSs are proposed. These concepts focus fine-grained adaptation of DBMS architectures and are realized through asynchronous programming models. These programming models decouple the implementation of DBMS components from fine-grained architectural optimization. Thereby, optimizers can derive novel architectures better fitting individual DBMS components, leading to high and robust DBMS performance under changing conditions.
- KonferenzbeitragAdaptive XML access control based on query nesting, modification and simplification(Datenbanksysteme in Business, Technologie und Web, 11. Fachtagung des GIFachbereichs “Datenbanken und Informationssysteme” (DBIS), 2005) Böttcher, Stefan; Steinmetz, RitaAccess control is an important aspect in guaranteeing data privacy within XML data sources which are accessed by users with different access rights. The goal of predicative access control for XML data sources is to use XPath expressions to describe that fragment of a given document or database that can be accessed by queries of a certain user. Our approach to access control hides the XML data source within an access control module which implements a combination of two secure query execution plans. The first query execution plan works on copied secure fragments, whereas the second query execution plan transforms a given query into another query that respects all the access rights. For each query the appropriate secure execution plan is determined depending on the query and the user's access rights.
- KonferenzbeitragAdmission Control für kontinuierliche Anfragen(Datenbanksysteme für Business, Technologie und Web (BTW 2015), 2015) Michelsen, Timo; Grawunder, Marco; Ludmann, Cornelius; Appelrath, H.-JürgenÜberlast bedeutet, dass an ein System mehr Anforderungen gestellt werden, als es erfüllen kann. Im schlechtesten Fall ist es nicht mehr ansprechbar oder stürzt ab. Für Datenbankmanagementsysteme (DBMS) existiert eine spezielle Komponente, Admission Control (AC) genannt, welche die Systemlast überwacht, eintreffende Anfragen vor deren Ausführung überprüft und ggfs. zurückstellt. Für kontinuierliche Anfragen, welche permanent ausgeführt werden, reicht diese Art von AC jedoch nicht aus: Es kann zur Konfliktlösung nicht mehr auf die Terminierung einer Anfrage gewartet werden. Zudem ist die Verarbeitung datengetrieben, d. h. Umfang und Inhalt der Daten können stark variieren. Diese Arbeit stellt ein Konzept vor, wie eine flexible und anpassbare AC-Komponente für kontinuierliche Anfragen auf Basis eines Event-Condition-Action-Modells (ECA) umgesetzt werden kann. Zur Regeldefinition wird die einfache Sprache CADL vorgestellt, die eine hohe Flexibilität und Anpassbarkeit der kontinuierlichen AC an konkrete Systeme und Hardware erlaubt. Die Evaluation zeigt mittels Odysseus, einem Framework für Datenstrommanagementsysteme, dass das Konzept effizient funktioniert und effektiv zur Lastkontrolle und Ergreifung von Maßnahmen zur Lastreduktion eingesetzt werden kann.
- KonferenzbeitragAdvanced cardinality estimation in the XML query graph model(Datenbanksysteme für Business, Technologie und Web (BTW), 2011) Weiner, Andreas M.Reliable cardinality estimation is one of the key prerequisites for effective cost-based query optimization in database systems. The XML Query Graph Model (XQGM) is a tuple-based XQuery algebra that can be used to represent XQuery expressions in native XML database management systems. This paper enhances previous works on reliable cardinality estimation for XQuery and introduces several inference rules that deal with the unique features of XQGM, such as native support for Structural Joins, nesting, and multi-way merging. These rules allow to estimate the runtime cardinalities of XQGM operators. Using this approach, we can support classical join reordering with appropriate statistical information, perform cost-based query unnesting, and help to find the best evaluation strategy for value-based joins. The effectiveness of our approach for query optimization is evaluated using the query optimizer of XTC.
- TextdokumentAggregate-based Training Phase for ML-based Cardinality Estimation(BTW 2021, 2021) Woltmann, Lucas; Hartmann, Claudio; Habich, Dirk; Lehner, WolfgangCardinality estimation is a fundamental task in database query processing and optimization. As shown in recent papers, machine learning (ML)-based approaches may deliver more accurate cardinality estimations than traditional approaches. However, a lot of training queries have to be executed during the model training phase to learn a data-dependent ML model making it very time-consuming. Many of those training or example queries use the same base data, have the same query structure, and only differ in their selective predicates. To speed up the model training phase, our core idea is to determine a predicate-independent pre-aggregation of the base data and to execute the example queries over this pre-aggregated data. Based on this idea, we present a specific aggregate-based training phase for ML-based cardinality estimation approaches in this paper. As we are going to show with different workloads in our evaluation, we are able to achieve an average speedup of 63 with our aggregate-based training phase and thus outperform indexes.
- KonferenzbeitragÄhnlichkeitssuche in Musik-Datenbanken mit Hilfe von Visualisierungen(BTW 2003 – Datenbanksysteme für Business, Technologie und Web, Tagungsband der 10. BTW Konferenz, 2003) Hinneburg, Alexander; Hinneburg, AlexanderÄhnlichkeitssuche in Datenbanken wurde bisher in vielen Bereichen erfolgreich angewendet. Jedoch gibt es vergleichsweise wenige Arbeiten, die sich mit Ähnlichkeitssuche in Musikdaten beschäftigen. Da derzeit immer mehr Musik über das Internet verfügbar wird, stößt dieser Bereich zunehmend bei vielen Anwendungsgruppen auf reges Interesse. Bisherige Suchverfahren lassen sich aber nur im beschränkten Maße an die vielfältigen Anwendungsszenarien anpassen. Meist läßt sich dies nur über die Auswahl einer abstrakten Metrik realisieren. Jedoch ist es ein ungelöstes Problem, wie der Benutzer dem Suchsystem mitteilen kann, welche Aspekte bei der Suche für eine Aufgabe relevant sind. Diese Arbeit stellt einen Ansatz vor, der versucht, die sogenannte semantische Lücke zwischen Benutzer und System durch einer Kombination aus konventioneller Ähnlichkeitssuche mit interaktiven Visualisierungen zu überbrücken. Dafür wurde eine neue Feature-Extraktionsmethode für Musikdaten entwickelt, die gleichzeitig für eine Visualisierung geeignet ist. Die abgeleitete Visualisierung beschreibt statistische Eigenschaften des Musikstücks. Mit Hilfe der Visualisierung kann die Ähnlichkeit zweier Musikstücke auf herkömmliche Weise akustisch, aber auch visuell bewertet werden. Der visuelle Weg ist viel schneller als das akustische Durchhören verschiedener Resultate und ermöglicht so die Verwendung von Relevance Feedback, mittels dessen das System sich iterativ an die Vorstellungen des Benutzers anpassen kann. Wir haben unseren Ansatz mit einer bekannten Methode für Musik- Ähnlichkeitssuche verglichen und demonstrieren die Effektivität anhand von Anwendungsbeispielen.
- KonferenzbeitragAIMS: an SQL-based system for airspace monitoring(Datenbanksysteme für Business, Technologie und Web (BTW), 2011) Schüller, Gereon; Behrend, AndreasThe “Airspace Monitoring System” (AIMS) is a system for monitoring and analyzing flight data streams with respect to the occurrence of arbitrary complex events. It is a general system that allows for a comprehensive analysis of aircraft movements, in contrast to already existing tools which focus on a single task like flight delay detection. For instance, the system is able to detect critical deviations from the current flight plan, abnormal approach parameters of landing flights as well as areas with an increased risk of collisions. To this end, tracks are extracted from cluttered radar data and SQL views are employed for a timely processing of these tracks. Additionally, the data is stored for later analysis.