Exploiting Versions for Handling Updates in Broadcast Disks
Evaggelia Pitoura, Panos K. Chrysanthis · 1999
Recently, broadcasting has attracted considerable attention as a means of disseminating information to large client populations in both wired and wireless settings. In this paper, we exploit versions to increase the concurrency of client transactions in the presence of updates. We consider three alternative mediums for storing versions: (a) the air: older versions are broadcast along with current data, (b) the client's local cache: older versions are maintained in cache, and (c) a local database or warehouse at the client: part of the server's database is maintained at the client in the form of a multiversion materialized view. The proposed techniques are scalable in that they provide consistency without any direct communication from clients to the server. Performance results show that the overhead of maintaining versions can be kept low, while providing a considerable increase in concurrency. 1 Introduction While traditionally data are delivered from servers to clients on demand, a...