Computer Science Department
School of Computer Science, Carnegie Mellon University


Improving Mobile Database Access
Over Wide-Area Networks Without Degrading Consistency

Niraj Tolia*, Mahadev Satyanarayanan, Adam Wolbach

January 2007


Keywords: Content addressable storage, mobile databases, wide-area networks, replicase, bandwidth optimization

We report on the design, implementation, and validation of a system called Cedar that enables mobile database access with good performance over low-bandwidth networks. This is accomplished without degrading consistency. Cedar exploits the disk storage and processing power of a mobile client to compensate for weak connectivity. Its central organizing principle is that even a stale client replica can be used to reduce data transmission volume from a database server. The reduction is achieved by using content addressable storage to discover and elide commonality between client and server results. This organizing principle allows Cedar to use an optimistic approach to solving the difficult problem of database replica control. For read-write workloads, our experiments show that Cedar improves throughput by 39% to as much as 224% while reducing response time by 28% to as much as 79%.

29 pages

*Department of Electrical and Computer Engineering, Carnegie Mellon University

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