Access path selection in a relational database management system

Selinger, Patricia G.; Astrahan, M. M.; Chamberlin, Donald D.; Lorie, Raymond A.; Price, Thomas G.

doi:10.1145/582095.582099

Cited by 1,403 publications

(339 citation statements)

References 11 publications

Supporting

Mentioning

332

Contrasting

Unclassified

Order By: Relevance

“…However, in our case we make calls into the database to extract costs by leveraging Explain Plan and the LEADING hint. The complexity of Algorithm 1 is O(2n) (where n is the number of tables); which is the same as the classic algorithm for query optimization [11], so our approach scales in a similar fashion. Even though this is exponential, OLTP queries typically don't operate on over more than ten tables.…”

Section: Join Order Enumerationmentioning

confidence: 99%

“…The identity of the inner relation and the set of tables comprising the outer relation uniquely determine the estimated best cost for an individual join operator. This is true regardless of the in which the outer relation was derived [11]. For convenience in our presentation, we call this information the operator's id, because we use it to represent an operator in the BIP.…”

Section: Join Order Enumerationmentioning

confidence: 99%

“…The bottom-up structure of the algorithm follows similarly to the classic dynamic programming algorithm for query optimization [11]. However, in our case we make calls into the database to extract costs by leveraging Explain Plan and the LEADING hint.…”

Section: Join Order Enumerationmentioning

confidence: 99%

See 2 more Smart Citations

Partitioning of web applications for hybrid cloud deployment

Kaviani

Wohlstadter

Lea

2014

J Internet Serv Appl

View full text Add to dashboard Cite

Hybrid cloud deployment offers flexibility in trade-offs between the cost-savings/scalability of the public cloud and control over data resources provided at a private premise. However, this flexibility comes at the expense of complexity in distributing a system over these two locations. For multi-tier web applications, this challenge manifests itself primarily in the partitioning of application-and database-tiers. While there is existing research that focuses on either application-tier or data-tier partitioning, we show that optimized partitioning of web applications benefits from both tiers being considered simultaneously. We present our research on a new cross-tier partitioning approach to help developers make effective trade-offs between performance and cost in a hybrid cloud deployment. The general approach primarily benefits from two technical improvements to integer-programming based application partitioning. First, an asymmetric cost-model for optimizing data transfer in environments where ingress and egress data-transfer have differing costs, such as in many infrastructure as a service platforms. Second, a new encoding of database query plans as integer programs, to enable simultaneous optimization of code and data placement in a hybrid cloud environment. In two case studies the approach results in up to 54% reduction in monetary costs compared to a premise only deployment and 56% improvement in response time compared to a naive partitioning where the application-tier is deployed in the public cloud and the data-tier is on private infrastructure.

show abstract

Section: Join Order Enumerationmentioning

confidence: 99%

Section: Join Order Enumerationmentioning

confidence: 99%

See 1 more Smart Citation

Partitioning of web applications for hybrid cloud deployment

Kaviani

Wohlstadter

Lea

2014

J Internet Serv Appl

View full text Add to dashboard Cite

show abstract

“…Since their rows and columns may contain different values, i.e., different f loor and ceiling attributes, we first align their rows and columns. .size} by the containment assumption [14], which states that each individual value in a smaller set always matches some value from the larger set. It is a common assumption in the literature on size estimation.…”

Section: Size Estimates For Unionmentioning

confidence: 99%

Deriving predicate statistics in datalog

Liang

Kifer

2010

Proceedings of the 12th International ACM SIGPLAN Symposium on Principles and Practice of Declarative Programming

View full text Add to dashboard Cite

Database query optimizers rely on data statistics in selecting query execution plans. Similar query optimization techniques are desirable for deductive databases and, to make this happen, we need to be able to collect data statistics for Datalog predicates. The difficulty is, however, that Datalog predicates can be recursive. In this paper, we propose an algorithm, called SDP, that estimates Datalog query sizes efficiently by maintaining the statistical dependency information for derived predicates. Base predicate statistics are computed and summarized using dependency matrices, and derived predicate statistics are computed by evaluating rules in an abstract way with rule bodies replaced with algebraic expressions over the dependency matrices. Recursive rules are handled by a fixed point evaluation. Our experimental study validates that: 1) SDP produces better query size estimates than using base predicate statistics and propagating them to derived predicates using the argument independence assumption; 2) the estimates largely preserve the relative order of real query sizes and thus can be used to guide cost based query optimizers.

show abstract

“…Aus diesem Grund ist es sehr schwierig, Selektivitäten für Prädikate anzugeben, um die Größe von Zwischenergebnissen abschätzen zu können. Daher müssen Defaultwerte für Selektivitäten, wie in [16] aufgeführt, herangezogen werden.…”

Section: Kostenmodellunclassified

Ankopplung heterogener Anwendungssysteme an Föderierte Datenbanksysteme durch Funktionsintegration

Härder¹,

Hergula

2002

Informatik Forsch Entw

View full text Add to dashboard Cite

Zusammenfassung.Mit der zunehmenden Zahl an Anwendungssystemen, welche Datenbank und zugehörige Anwendung kapseln, ist die reine Datenintegration nicht mehr ausreichend. Stattdessen können die Daten des Anwendungssystems nur nochüber vordefinierte Funktionen abgefragt werden. Sollen Daten und Funktionen integriert werden, so ist eine Kombination von deklarativen Anfragen und dem Zugriff auf Funktionen erforderlich. In diesem Aufsatz stellen wir einen Middleware-Ansatz vor, der diese erweiterte und neuartige Form der Integration unterstützt. Hierzu werden zunächst die Probleme der Funktionsintegration erörtert und eine Spezifikationssprache eingeführt, die föderierte Funktionen zu bilden und diese mehreren lokalen Funktionen der zu integrierenden Anwendungssysteme zuzuordnen erlaubt. Anschließend zeigen wir, wie die zugehörige Ausführungskomponente -in unserem Fall ein Workflow-Managementsystem -an ein Föderiertes Datenbanksystem mittels eines Wrappers gekoppelt wird, um die Integration von Daten und Funktionen zu ermöglichen. Dabei wird die zu unterstützende Funktionalität innerhalb des Wrappers sowie deren Auswirkungen auf die Anfrageverarbeitung als auch das zugehörige Kostenmodell untersucht. Abschließend wird ein Eindruck von der Performanz der vorgestellten Architektur vermittelt. Abstract.With the emergence of so-called application systems which encapsulate databases and related application components, pure data integration using, for example, a federated database system is not possible anymore. Instead, access via predefined functions is the only way to get data from an application system. As a result, retrieval of such heterogeneous and encapsulated data sources needs a combination of generic query and predefined function access. In this paper, we present a middleware approach supporting such a novel and extended kind of integration. After a brief characterization of function integration, we introduce a mapping language for the specification of federated functions combining functionality of one or more application systems (local functions) to be integrated. We discuss how the related execution component, a workflow management system, can be connected via a wrapper to a federated database system to enable the integration of data as well as functions. Furthermore, we explore the use of a query processing functionality within the wrapper and its effect on the overall query evaluation as well as a related cost model. Finally, we give a first impression of the performance to be expected from our architecture.

show abstract

Access path selection in a relational database management system

Cited by 1,403 publications

References 11 publications

Partitioning of web applications for hybrid cloud deployment

Partitioning of web applications for hybrid cloud deployment

Deriving predicate statistics in datalog

Ankopplung heterogener Anwendungssysteme an Föderierte Datenbanksysteme durch Funktionsintegration

Contact Info

Product

Resources

About