|Title:||Parallel database query optimization using genetic algorithm|
Hong Kong Polytechnic University -- Dissertations
Department of Applied Mathematics
|Pages:||ii, 115 leaves : ill. ; 30 cm|
|Abstract:||Database query optimization has long been one of the difficult problems in the area of database system researches. For a query submitted against a database, a large number of different ways, or so called query execution plans, can be used to retrieve the data from the database. The objective of query optimization is to find the plan that minimizes the execution time or the usage of system resources. It has been known that the search space of query execution plans is growing exponentially when number of tables involved is increasing. In parallel database system, the consideration of processors allocation further complicates the problem. For this kind of combinatorial optimization problem, exhaustive search is not a practical solution because it requires huge amount of time to find the optimal plan. Instead, different heuristic methods have been developed by researchers to tackle the problems. In view of the growing popularity and success of applying genetic algorithm (GA) to solve combinatorial optimization problems in different areas, this dissertation explores the way to use GA to solve the parallel database query optimization problem. Integrated approach is used in this dissertation such that the two subproblems in parallel database query optimization, join ordering and processors allocation, are considered simultaneously. Detail implementation of the algorithm like what data structure is used to represent the population of chromosomes and what kinds of genetic operators are used to introduce diversity into the population are presented in the dissertation such that reader will get a clear picture of how GA can be applied to solve the query optimization problem. The results of a number of simulation tests are also presented at the end to demonstrate that GA has superior performance to some heuristic algorithms in optimizing different kinds of queries.|
Files in This Item:
|b15235749.pdf||For PolyU Staff & Students||3.16 MB||Adobe PDF||View/Open|
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item: