DMCA
Query Caching and Optimization in Distributed Mediator Systems (1996)
| Venue: | In Proc. of ACM SIGMOD Conf. on Management of Data |
| Citations: | 195 - 11 self |
BibTeX
@INPROCEEDINGS{Adali96querycaching,
author = {S. Adali and K. S. Candan and Y. Papakonstantinou and V. S. Subrahmanian},
title = {Query Caching and Optimization in Distributed Mediator Systems},
booktitle = {In Proc. of ACM SIGMOD Conf. on Management of Data},
year = {1996},
pages = {137--148}
}
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Abstract
Query processing and optimization in mediator systems that access distributed non-proprietary sources pose many novel problems. Cost-based query optimization is hard because the mediator does not have access to source statistics information and furthermore it may not be easy to model the source's performance. At the same time, querying remote sources may be very expensive because of high connection overhead, long computation time, financial charges, and temporary unavailability. We propose a costbased optimization technique that caches statistics of actual calls to the sources and consequently estimates the cost of the possible execution plans based on the statistics cache. We investigate issues pertaining to the design of the statistics cache and experimentally analyze various tradeoffs. We also present a query result caching mechanism that allows us to effectively use results of prior queries when the source is not readily available. We employ the novel invariants mechanism, which s...
Keyphrases
distributed mediator system query caching statistic cache high connection overhead costbased optimization technique prior query various tradeoff possible execution plan remote source actual call non-proprietary source source statistic information mediator system cost-based query optimization novel invariant mechanism query processing temporary unavailability many novel problem query result financial charge long computation time
