BACKGROUND Fragmentation of database indexes can have a significant impact on
input/output (I/O) costs associated with responding to database queries. For example, an …

Decision support queries that scan large indexes can suffer significant degradation in I/O
performance due to index fragmentation. DBAs rely on rules of thumb that use index size …

Today's extensible object-relational database management systems (ORDBMSs) are being
deployed to support nontraditional applications such as dynamic web servers and …

Designing and tuning access methods (AMs) has always been more of a black art than a
rigorous discipline, with performance assessments being mostly reduced to presenting …

Therefore, index structures can easily be used in queries. A typical example is a join cursor
which consumes the outputs of two underlying cursors. Most of our work is however not …

The term\online" has become an all-too-common addendum to database system names of
the day. In this article we reexamine the notion of processing queries online. We distinguish …

The standard mechanisms for query selectivity estimation used in relational database
systems rely on properties specific to the attribute types. For example, histograms and …

基于我国经济与技术发展的需求, 文章阐述了专利预警应用的背景和专利文献相似度研究的意义
. 在系统地调查与计量国内外相关文献研究的基础上, 总结专利预警研究的主要侧重点 …