Query Scrambling for Bursty Data Arrival.
Query Scrambling for Bursty Data Arrival.
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Date
1998-10-15
Authors
Amsaleg, Laurent
Franklin, Michael J.
Tomasic, A.
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Abstract
Distributed databases operating over wide-area networks, such as the
Internet, must deal with the unpredictable nature of the performance
of communication. The response times of accessing remote sources may
vary widely due to network congestion, link failure, and other
problems. In this paper we examine a new class of methods, called
query scrambling, for dealing with unpredictable response times.
Query scrambling dynamically modifies query execution plans on-the-fly
in reaction to unexpected delays in data access. We explore various
choices in the implementation of these methods and examine, through a
detailed simulation, the effects of these choices. Our experimental
environment considers pipelined and non-pipelined join processing in a
client with multiple remote data sources and it focuses on bursty
arrivals of data. We identify and study a number of the basic
trade-offs that arise when designing scrambling policies for the
bursty environment. Our performance results show that query
scrambling is effective in hiding the impact of delays on query
response time for a number of different delay scenarios.
(Also cross-referenced as UMIACS-TR-96-84)