文章基本信息

标题：Execution Planning for Continuous Queries over Dissemination Network of Data Aggregators
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作者：M .Naresh Kumar ; R.Sailaja
期刊名称：International Journal of Computer Trends and Technology
电子版ISSN：2231-2803
出版年度：2013
卷号：4
期号：10-1
出版社：Seventh Sense Research Group
摘要：Normally continuous queries are those used, to observe the dynamically changing data and to give results helpful for Online decision making. Generally a user wants to achieve the value of few aggregation functions over shared data items, for example, to regulate when the value of a stock portfolio exceeds a threshold. We focus on approaches and techniques to assign such dynamically changing data to a large number of users with high accuracy, efficiency, and scalability. In these queries a client maintains a consistency requirement as part of the query. We come up with a minimal –cost based approach to answer continuous aggregation queries using a network of aggregators of dynamic data items. In that network of data aggregators, each data aggregator handles a set of data items at definite coherencies. Our technique is splitting a client query into subqueries and executing subqueries on properly chosen data aggregators with their respective subquery incoherency bounds. We give a mechanism for collecting the optimal set of subqueries with their inconsistency bounds which satisfies client query’s coherency requirement with minimum number of update messages issued from aggregators to the client. We layout a cost based model which can be used to evaluating the number of messages prescribed to satisfy the client specified incoherency bound .
关键词：Coherency; Continuous queries; Cost; Distributed query processing; Data dissemination; Performance