On Strategies for Allocating Replicas of Mobile Databases

Budiarto  Kaname HARUMOTO  Masahiko TSUKAMOTO  Shojiro NISHIO  Tetsuya TAKINE  

IEICE TRANSACTIONS on Information and Systems   Vol.E81-D   No.1   pp.37-46
Publication Date: 1998/01/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Databases
databases,  mobile computing,  replica allocation,  evaluation,  

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Mobile databases will play an important role in mobile computing environment, to provide data storing and data retrieval functionalities which are needed by most applications. In mobile computing environment, the wireless communication poses some problems, which require us to minimize its use. Replication is a database technique that is commonly used to fulfill the requirement in minimizing network usage. In this paper, we propose two replica allocation strategies, called primary-copy tracking replica allocation (PTRA) and user majority replica allocation (UMRA), which are better suited to the mobile computing environment. Their proposals are intended to cope with cost performance issues in data replication due to user mobility in mobile computing environment. To investigate their effectiveness, we provide access cost analysis and comparison on these strategies and the static replica allocation (SRA) strategy. We show that our proposed strategies outperform the SRA strategy when user mobility (inter-cell movement) is relatively low as compared with data access rate.