Caching and Concurrency Control in a Mobile Client/Sever Computing Environment

이동 클라이언트/서버 컴퓨팅환경에서의 캐싱 및 동시성 제어

  • 이상근 (고려대학교 컴퓨터학과) ;
  • 황종선 (고려대학교 사범대학 컴퓨터교육과) ;
  • 이원규 (고려대학교 사범대학 컴퓨터교육과) ;
  • 유헌창 (고려대학교 사범대학 컴퓨터교육과)
  • Published : 1999.08.01

Abstract

이동 컴퓨팅 환경에서 자주 접근하는 데이터에 대한 캐싱은 무선 채널의 좁은 대역폭에서 경쟁을 줄일 수 있는 유용한 기술이다. 그러나, 트랜잭션 캐시 일관성을 지원하는 전통적인 클라이언트/서버 전략은 클라이언트와 서버간에 많은 양의 통신을 필요로 하기 때문에 이동 클라이언트/서버 컴퓨팅 환경에서는 적절하지 않다. 본 논문에서는 브로드캐스트-기반 캐시 무효화 정책을 사용하면서 트랜잭션 캐시 일관성을 지원하는 OCC-UTS (Optimistic Concurrency Control with Update TimeStamp) 프로토콜을 제안한다. 접근한 데이터에 대한 일관성 검사 및 완료 프로토콜은 캐시 무효화 과정의 내부 과정으로 완전 분산 형태로 효율적으로 구현되며, 일관성 체크의 대부분이 이동 클라이언트에서 수행된다. 또한, 분석 모델에 기반한 성능 비교를 통해, 본 논문에서 제안하는 OCC-UTS 프로토콜이 다른 경쟁 프로토콜보다 높은 트랜잭션 처리율을 얻으며, 데이터 항목을 자주 접근하면 할수록 지역 캐시를 사용하는 OCC-UTS 프로토콜이 더 효율적임을 보인다. 이동 클라이언트의 접속 단절에 대해서는 무효화 브로드캐스트 윈도우를 크게 하여 접속 단절에 적절히 대처할 수 있다.Abstract In a mobile computing environment, caching of frequently accessed data has been shown to be a useful technique for reducing contention on the narrow bandwidth of the wireless channels. However, the traditional client/server strategies for supporting transactional cache consistency that require extensive communications between a client and a server are not appropriate in a mobile client/server computing environment. In this paper, we propose a new protocol, called OCC-UTS (Optimisitic Concurrency Control with Update TimeStamp), to support transactional cache consistency in a mobile client/server computing environment by utilizing the broadcast-based solutions for the problem of invalidating caches. The consistency check on accessed data and the commitment protocol are implemented in a truly distributed fashion as an integral part of cache invalidation process, with most burden of consistency check being downloaded to mobile clients. Also, our experiments based on an analytical model substantiate the basic idea and study the performance characteristics. Experimental results show that OCC-UTS protocol without local cache outperforms other competitor protocol, and the more frequent a mobile client accesses data items the more efficient OCC-UTS protocol with local cache is. With respect to disconnection, the tolerance to disconnection is improved if the invalidation broadcast window size is extended.

Keywords

References

  1. Proceedings of ACM SIGMOD Conference on Management of Data Sleepers and Workaholics : Caching in Mobile Environments D. Barbara;T. Imielinsky
  2. Proceedings of the 13th International Conference on Data Engineering On Incremental Cache Coherency Schemes in Mobile Computing Environments J. Cay;K. Tan;B. C. Ooi
  3. Proceedings of the 13th International Conference on Data Engineering Quantifying Complexity and Performance Gains of Distributed Caching in a Wireless Network Environment C. F. Fong;C. S. Lui;M. H. Wong
  4. ACM/Baltzer Mobile Networks and Applications v.2 no.2 Bit-Sequences: An Adaptive Cache Invalidation Method in Mobile Client/Server Environments J. Jing;A. Elmagarmid;A. Helal;R. Alonso
  5. Proceedings of the 12th International Conference on Data Engineering Energy-efficient Caching for Wireless Mobile Computing K. L. Wu;P. S. Yu;M. S. Chen
  6. ACM Transactions on Database Systems v.22 no.3 Transactional Client-Server Cache Consistency : Alternatives and Performance M. J. Franklin;M. J. Carey;M. Livny
  7. Proceedings of the 12th International Conference on Distributed Computing Systems Certification Reports : Supporting Transactions in Wireless Systems D. Barbara
  8. Proceedings of International Conference on Information and Knowledge Management Commit-Reordering Validation Scheme for Transaction Scheduling in Client-Server Based Teleputing Systems : COREV Y. Lee;S. Moon
  9. Proceedings of the 9th International Workshop on Database and Expert Systems Applications Supporting Read-Only Transactions in Wireless Broadcasting E. Pitoura
  10. Concurrency Control and Recovery in Database Systems P. A. Bernstein;V. Hadzilacos;N. Goodman
  11. ACM Transactions on Database Systems v.6 no.2 On Optimistic Methods for Concurrency Control H. T. Kung;J. T. Robinson
  12. Information Systems v.9 no.2 Observations on Optimistic Concurrency Control Schemes T. Harder
  13. ACM SIGMOD Record v.24 no.4 Mobile Computing and Databases: Anything New? M. H. Dunham;A. S. Helal
  14. Communications of the ACM Wireless Mobile Computing : Challenges in Data Management T. Imielinski;B. R. Badrinath