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2008

Adaptive optimization of join trees for multi-join queries over sensor streams

9 years 8 months ago
Adaptive optimization of join trees for multi-join queries over sensor streams
Data processing applications for sensor streams have to deal with multiple continuous data streams with inputs arriving at highly variable and unpredictable rates from various sources. These applications perform various operations (e.g. filter, aggregate, join etc) on incoming data streams in real-time according to predefined queries or rules. Since the data rate and data distribution fluctuate over time, an appropriate join tree for processing join queries must be adaptively maintained in response to dynamic changes to prevent rapid degradation of the system performance. In this paper, we address the problem of finding an optimal join tree that maximizes throughput for sliding window based multi-join queries over continuous data streams and prove its NP-Hardness. We present a dynamic programming algorithm, OptDP, which produces the optimal tree but runs in an exponential time in the number of input streams. We then present a polynomial time greedy algorithm, XGreedyJoin. We tested the...
Joseph S. Gomes, Hyeong-Ah Choi
Added 12 Dec 2010
Updated 12 Dec 2010
Type Journal
Year 2008
Where INFFUS
Authors Joseph S. Gomes, Hyeong-Ah Choi
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