Query Optimization To Meet Performance Targets for Wide Area Applications
Louiqa Raschid
Vladimir Zadorozhny Contact Information
Affiliation:
University of Pittsburgh
3129 A.V. Williams Building
University of Maryland
College Park, MD 20742
Phone: (301) 405-6747
Fax : (301) 314-9658
Email: louiqa@umiacs.umd.edu
http://www.umiacs.umd.edu/~louiqa
WWW PAGE
List of Supported Students and Staff (optional)
Qing Lu, Graduate Assistant
Laura Bright, Graduate Assistant
Avigdor Gal from Technion, Israel consulted on this research.
Project Award Information
Keywords
Wide-area networks; distribution of access costs; expected value and expected delay; performance target sensitive optimizer.
Project Summary
The goal of this research project is to develop a performance target (PT) sensitive optimizer. Performance targets are relevant in the noisy wide area environment where access costs to Internet accessible WebSources exhibit transient behavior, and are best characterized by a distribution of access costs. A PT sensitive optimizer will have the ability to differentiate among multiple alternate WebSources, and to choose a combination of WebSources so as to best meet a performance target for some query (and its query evaluation plan). The ability to meet a target is quantified by a utility function. Existing optimizers and their cost model consider either specific values or expected values for access costs, and are not sensitive to performance targets. This approach characterizes each plan with the expected value of the cost of the plan, as well as the delay; delay is the deviation above the expected value. A Cost--Delay measure (CDM) combines these two values using a cost factor and a delay factor. A simulation based study of the optimizer's aggregate behavior, for a set of queries and a set of remote relations on WebSources will be used to correlate the PT optimizer's selection of plans and WebSources with its success in maximizing utility or meeting a performance target. The results of this project will provide a tunable optimizer for noisy environments that allows applications to be sensitive to performance targets and to better utilize Internet resources.
Goals, Objectives, and Targeted Activities
The goals and activities of this project include the following:
Indication of Success
Project Impact
GPRA Outcome Goals
Project References
Area Background
Area References
A list of references on mediator and wrapper architectures can be obtained in
the following:
Tomasic, Anthony and Raschid, Louiqa and Valduriez, Patrick.
Scaling Access to Distributed Heterogeneous Databases: A Data Model
and Query Processing Techniques in Disco.
IEEE Transactions on Knowledge and Data Engineering,
Volume 10, Number 4, July 1998.
A list of references on reactive query evaluation techniques can be obtained
in the following:
IEEE Data Engineering Bulletin, Volume 23, Number 2, Franklin, Michael, editor,
2000.
Potential Related Projects