Multiversion reconciliation for mobile databases

Abstract

As mobile computing devices become more and more popular mobile databases have started gaining popularity. An important feature of these database systems is their ability to allow optimistic replication of data by permitting disconnected mobile devices to perform local updates on replicated data. The fundamental problem in this approach is the reconciliation problem, i.e. the problem of serializing potentially conflicting updates performed by local transactions on disconnected clients on all copies of the database. We introduce a new algorithm that combines multiversion concurrency control schemes on a server with reconciliation of updates from disconnected clients. The scheme generalizes to multiversion systems, the single version optimistic method of reconciliation, in which client transactions are allowed to commit on the server iff data items in their read sets are not updated on the server after replication.