Executing incoherency bounded continuous queries at web data aggregators

Continuous queries are used to monitor changes to time varying data and to provide results useful for online decision making. Typically a user desires to obtain the value of some function over distributed data items, for example, to determine when and whether (a) the traffic entering a highway from multiple feed roads will result in congestion in a thoroughfare or (b) the value of a stock portfolio exceeds a threshold. Using the standard Web infrastructure for these applications will increase the reach of the underlying information. But, since these queries involve data from multiple sources, with sources supporting standard HTTP (pullbased) interfaces, special query processing techniques are needed. Also, these applications often have the flexibility to tolerate some incoherency, i.e., some differences between the results reported to the user and that produced from the virtual database made up of the distributed data sources. In this paper, we develop and evaluate client-pull-based t...

• Type: Conference
• Year: 2005
• Where: WWW
• Authors: Rajeev Gupta, Ashish Puri, Krithi Ramamritham
• Keywords: Data Refresh Times, Data Sources, Internet Technology, Queries Involve Data, WWW 2005