Update-Pattern-Aware Modeling and Processing of Continuous Queries

A defining characteristic of continuous queries over on-line data streams, possibly bounded by sliding windows, is the potentially infinite and time-evolving nature of their inputs and outputs. New items continually arrive on the input streams and new results are continually produced. Additionally, inputs expire by falling out of range of their sliding windows and results expire when they cease to satisfy the query. This impacts continuous query processing in two ways. First, data stream systems allow tables to be queried alongside data streams, but in terms of query semantics, it is not clear how updates of tables are different from insertions and deletions caused by the movement of the sliding windows. Second, many interesting queries need to store state, which must be kept up-to-date as time goes on. Therefore, query processing efficiency depends highly on the amount of overhead involved in state maintenance. In this paper, we show that the above issues can be solved by understandi...

• Type: Conference
• Year: 2005
• Where: SIGMOD
• Authors: Lukasz Golab, M. Tamer Özsu
• Keywords: Continuous Query Processing, Continuous Query Semantics, Database, Query Processing Efficiency, SIGMOD 2005