Proqid

Abstract

In a number of application areas, distributed database systems can be used to provide persistent storage of data while providing efficient access for both local and remote data. With an increasing number of sites (computers) involved in a query, the probability of failure at query time increases. Recovery has previously only focused on database updates while query failures have been handled by complete restart of the query. This technique is not always applicable in the context of large queries and queries with deadlines. In this paper we present an approach for partial restart of queries that incurs minimal extra network traffic during query recovery. Based on results from experiments on an implementation of the partial restart technique in a distributed database system, we demonstrate its applicability and significant reduction of query cost in the presence of failures.