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Proceedings of 16th International Conference on Distributed Computing Systems (1996)
Hong Kong
May 27, 1996 to May 30, 1996
ISSN: 1063-6927
ISBN: 0-8186-7398-2
pp: 458
Ling Liu , Dept. of Comput. Sci., Alberta Univ., Edmonton, Alta., Canada
C. Pu , Dept. of Comput. Sci., Alberta Univ., Edmonton, Alta., Canada
R. Barga , Dept. of Comput. Sci., Alberta Univ., Edmonton, Alta., Canada
Tong Zhou , Dept. of Comput. Sci., Alberta Univ., Edmonton, Alta., Canada
ABSTRACT
We define continual queries as a useful tool for monitoring of updated information. Continual queries are standing queries that monitor the source data and notify the users whenever new data matches the query. In addition to periodic refresh, continual queries include Epsilon Transaction concepts to allow users to specify query refresh based on the magnitude of updates. To support efficient processing of continual queries, we propose a differential re-evaluation algorithm (DRA), which exploits the structure and information contained in both the query expressions and the database update operations. The DRA design can be seen as a synthesis of previous research on differential files, incremental view maintenance, and active databases.
INDEX TERMS
query processing; active databases; differential evaluation; continual queries; updated information; periodic refresh; Epsilon Transaction concepts; differential reevaluation algorithm; database update operations; differential files; incremental view maintenance; active databases
CITATION

R. Barga, C. Pu, T. Zhou and L. Liu, "Differential evaluation of continual queries," Proceedings of 16th International Conference on Distributed Computing Systems(ICDCS), Hong Kong, 1996, pp. 458.
doi:10.1109/ICDCS.1996.507994
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