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Exploiting Correlated Attributes in Acquisitional Query Processing (2005)

By: Amol Deshpande, Carlos Guestrin, Wei Hong, and Sam Madden

Abstract: Sensor networks and other distributed information systems (such as the Web) must frequently access data that has a high per-attribute {ITacquisition} cost, in terms of energy, latency, or computational resources. When executing queries that contain several predicates over such expensive attributes, we observe that it can be beneficial to use correlations to automatically introduce low-cost attributes whose observation will allow the query processor to better estimate the selectivity of these expensive predicates. In particular, we show how to build {ITconditional plans} that branch into one or more sub-plans, each with a different ordering for the expensive query predicates, based on the runtime observation of low-cost attributes. We frame the problem of constructing the optimal conditional plan for a given user query and set of candidate low-cost attributes as an optimization problem. We describe an exponential time algorithm for finding such optimal plans, and describe a polynomial-time heuristic for identifying conditional plans that perform well in practice. We also show how to compactly model conditional probability distributions needed to identify correlations and build these plans. We evaluate our algorithms against several real-world sensor-network data sets, showing several-times performance increases for a variety of queries versus traditional optimization techniques.

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Amol Deshpande, Carlos Guestrin, Wei Hong, and Sam Madden (2005). "Exploiting Correlated Attributes in Acquisitional Query Processing." 21st International Conference on Data Engineering (ICDE). pdf            
BibTeX citation

@inproceedings{Deshpande+al:icde2005correlated,
author = {Amol Deshpande and Carlos Guestrin and Wei Hong and Sam Madden},
title = {Exploiting Correlated Attributes in Acquisitional Query Processing},
booktitle = {21st International Conference on Data Engineering (ICDE)},
year = {2005},
address = {Tokio},
month = {April},
wwwfilebase = {icde2005-deshpande-guestrin-hong-madden},
wwwtopic = {Sensor Networks}
}



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