A Light-Weight Distributed System for the processing of Replicated Counter-like Objects

Abstract: In order to increase availability in a distributed system some or all of the data items are replicated and stored at separate sites. This is an issue of key concern especially since there is such a proliferation of wireless technologies and mobile users. However, the concurrent processing of transactions at separate sites can generate inconsistencies in the stored information. We have built a distributed service that manages updates to widely deployed counter-like replicas. There are many heavy-weight distributed systems targeting large information critical applications. Our system is intentionally, relatively lightweight and useful for the somewhat reduced information critical applications. The service is built on our distributed concurrency control scheme which combines optimism and pessimism in the processing of transactions. The service allows a transaction to be processed immediately (optimistically) at any individual replica as long as the transaction satisfies a cost bound. All transactions are also processed in a concurrent pessimistic manner to ensure mutual consistency.