scispace - formally typeset
Search or ask a question
Topic

Data access

About: Data access is a research topic. Over the lifetime, 13141 publications have been published within this topic receiving 172859 citations. The topic is also known as: Data access.


Papers
More filters
Journal ArticleDOI
TL;DR: A semantic caching mechanism which allows data to be cached as a collection of possibly related blocks, each of which is the result of a previously evaluated query, is proposed.
Abstract: Caching of remote data in a mobile client's local storage can improve data access performance and data availability. Traditional approaches are page-based, without taking advantage of the semantics of cached data. It is difficult for a client to determine if a query could be answered entirely based on locally cached data, forcing it to contact the database server for additional data. We propose a semantic caching mechanism which allows data to be cached as a collection of possibly related blocks, each of which is the result of a previously evaluated query. We investigate mechanisms for transforming projection-selection queries to reuse cached data blocks. This avoids transmitting unwanted data items over low bandwidth wireless channels. Cache replacement techniques based on the semantics of cached data are also proposed. We describe the design of our prototype and study its performance.

81 citations

Patent
13 Aug 1976
TL;DR: In this article, an information storage facility with multiple level processors for relieving one or more external host computers or intelligent terminals from conventional time consuming record searching functions, such as record formatting, indexing, buffering and the like.
Abstract: An information storage facility with multiple level processors for relieving one or more external host computers or intelligent terminals from conventional time consuming record searching functions, such as record formatting, indexing, buffering and the like. Three processor levels are provided: a communications level for handling external communications, a DBMS level for performing syntax scanning, hashing and coding/decoding routines, and data access functions e.g. indexing, searching, buffering, blocking, deblocking, storage management, and error recovery functions; and a storage level for performing data storage and retrieval, error recovery and storage device management. A direct memory access bus is also provided which enables high speed data transfer among the several processors included within the storage facility and also external host computers or intelligent terminals.

81 citations

Patent
09 Oct 2003
TL;DR: In this paper, a system with multiple data stores receives a data access request that includes one or more variables, and the system determines which data store can service the data access requests by using mappings of the variables to the data stores in order to evaluate whether partition expressions for data stores overlap with the variables in the access request.
Abstract: A system with multiple data stores receives a data access request that includes one or more variables. The system determines which data store can service the data access request by using mappings of the variables to the data stores in order to evaluate whether partition expressions for the data stores overlap with the variables in the data access request. The data access request is then sent to the data stores corresponding to the partition expressions that overlap. The partition expressions can have one or more variables. The present invention supports multi-dimensional partitioning.

81 citations

Patent
27 Mar 2002
TL;DR: A system and method for controlling access to data within a hierarchically organized document, such as an XML document, is described in this paper, where the authors define a collection of entitlement expressions, which describe with arbitrarily fine granularity which users and user types may access the data.
Abstract: A system and method for controlling access to data within a hierarchically organized document, such as an XML document. Elements may have their access rights specified, for example as a variable in an XML tag. If not specified within an element of the document, access rights are inherited from its nearest ancestor. Specified access rights may refer to a collection of entitlement expressions, which describe with arbitrarily fine granularity which users and user types may access the data.

81 citations

Journal ArticleDOI
TL;DR: Data access becomes very fast—even faster than the common access to nonhierarchical data stored in matrices—and, in particular, cache misses are reduced considerably.
Abstract: Competitive numerical algorithms for solving partial differential equations have to work with the most efficient numerical methods like multigrid and adaptive grid refinement and thus with hierarchical data structures. Unfortunately, in most implementations, hierarchical data—typically stored in trees—cause a nonnegligible overhead in data access. To overcome this quandary—numerical efficiency versus efficient implementation—our algorithm uses space-filling curves to build up data structures which are processed linearly. In fact, the only kind of data structure used in our implementation is stacks. Thus, data access becomes very fast—even faster than the common access to nonhierarchical data stored in matrices—and, in particular, cache misses are reduced considerably. Furthermore, the implementation of multigrid cycles and/or higher order discretizations as well as the parallelization of the whole algorithm become very easy and straightforward on these data structures.

80 citations


Network Information
Related Topics (5)
Software
130.5K papers, 2M citations
86% related
Cloud computing
156.4K papers, 1.9M citations
86% related
Cluster analysis
146.5K papers, 2.9M citations
85% related
The Internet
213.2K papers, 3.8M citations
85% related
Information system
107.5K papers, 1.8M citations
83% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202351
2022125
2021403
2020721
2019906
2018816