MODEC: A Multi-Granularity Mobile Object-Oriented Database CachingMechanism, Prototype and Performance

  • Authors:

  • Boris Y. L. Chan;Hong Va Leong;Antonio Si;Kam Fai Wong

  • Affiliations:

  • Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. csylchan@comp.polyu.edu.hk;Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. cshleong@comp.polyu.edu.hk;Sun Microsystems Inc., Palo Alto, CA 94303, USA. antonio.si@eng.sun.com;Department of Systems Engineering and Engineering Management, The Chinese University of Hong Kong, Shatin, Hong Kong. kfwong@se.cuhk.edu.hk

  • Venue:
  • Distributed and Parallel Databases - Special issue on mobile data management and applications
  • Year:
  • 1999

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Abstract

An inherent limitation in mobile data access is due to theunreliable and low bandwidth wireless communication channel. Cachingof useful database items from database server in local storage ofmobile clients is effective in reducing data access latency andwireless bandwidth consumption. In the event of disconnection, cacheddata can also serve the purpose of partial query processing. In thispaper, we present the implementation and evaluate a new cachingmechanism for object-oriented database systems in a mobileenvironment called MODEC. MODEC possesses the capabilities ofperforming caching at multiple granularities and adapting to changesin data access pattern, providing improved performance throughtolerating limited inconsistency to read-only transactions. Thiscaching capabilities is supported via standard ODMG modelingconstructs. The prototype of MODEC is implemented using ODE database. Empirical system performance results are obtained from experiments onthe prototype with data from a real-life database. The results arevalidated against results obtained via detailed simulation studies onMODEC. Both sets of results are found to be consistent and are infavor of our MODEC mechanism in providing a feasible solution to themobile data access problem under the constraints in a mobileenvironment.