摘要 :
Caching of frequently accessed data has been shown to be a useful technique for reducing congestion on the narrow bandwidth of wireless channels. However, traditional client/server strategies for supporting transactional cache con...
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Caching of frequently accessed data has been shown to be a useful technique for reducing congestion on the narrow bandwidth of wireless channels. However, traditional client/server strategies for supporting transactional cache consistency, which require extensive communications between a client and a server, are not appropriate in a wireless mobile database. This paper proposes two, simple but effective, transactional cache consistency protocols for mobile read-only transactions by utilizing the broadcast-based solutions for the problem of invalidating caches. The novelty of our approach is that 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. The applicability of proposed techniques is also examined by an analytical study.
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摘要 :
Improved data processing capabilities and increased data storage capacity of mobile devices facilitate on-line internet transaction processing. When number of mobile clients involve in transaction processing, they make frequent re...
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Improved data processing capabilities and increased data storage capacity of mobile devices facilitate on-line internet transaction processing. When number of mobile clients involve in transaction processing, they make frequent requests for accessing the data item from the data base server. So such simultaneous access requests increase network overhead and thus poor response time. So to improve response time and to decrease network overhead, frequently accessed data items are cached. But data items that are cached should be properly invalidated and in this paper, an improved cache invalidation technique is proposed. The proposed technique provides implicit cache invalidation, increased transaction throughput, dependency preservation and decreased response time with reduced complexity in mobile devices. Performance analysis ensures decreased response time, increased throughput with reduced link cost.
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摘要 :
Data-shipping systems that allow inter-transaction caching raise the need of a transactional cache consistency maintenance (CCM) protocol because each client is able to cache a portion of the database dynamically. Deferred locking...
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Data-shipping systems that allow inter-transaction caching raise the need of a transactional cache consistency maintenance (CCM) protocol because each client is able to cache a portion of the database dynamically. Deferred locking (DL) is a new CCM scheme that is capable of reducing the communication overhead required for cache consistency checking. Due to its low communication overhead, DL could show a superior performance, but it tends to exhibit a high ratio of transaction abort. To cope with this drawback, we develop a new notion of shadow transaction, which is a backup-purpose one that is kept ready to replace an aborted transaction. This notion and the locking mechanism of DL have been incorporated into deferred locking with shadow transaction. Using a distributed database simulation model, we evaluate the performance of the proposed schemes under a wide range of workloads. (C) 2005 Elsevier B.V. All rights reserved.
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摘要 :
The well-developed traditional data management techniques need to be augmented with new approaches in order to continue to be effective in the mobile environment. In this paper, we focus on the challenge of maintaining integrity c...
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The well-developed traditional data management techniques need to be augmented with new approaches in order to continue to be effective in the mobile environment. In this paper, we focus on the challenge of maintaining integrity constraints in the presence of disconnections and expensive communication. Our approach of localization is to reformulate global constraints so as to enhance the autonomy of the mobile hosts in processing transactions. We show how this approach unifies techniques of maintaining replicated data with methods of enforcing polynomial inequalities. We also discuss how localization can be realized in PRO-MOTION, a flexible infrastructure for transaction processing in a mobile environment.
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