Implementation of federated query processing on Linked Data

As the number of Linked Data sets increases with more and more interconnections defined between them, querying a single data set is no longer enough for users who need data from mixed domains. The requirement to query data from different data sets motivates the research into federated queries. Network latency is one of the key factors which affect the performance of a federated query. The influence of network latency can be minimised by decreasing the number of remote requests, which is related to the number of joins. In this paper, we provide a mechanism for federated querying based on subject and sameAs grouping techniques. Exploiting the benefits of proposed grouping methods, the number of joins during a federated query has been reduced, thus improving the performance of the entire query. We have evaluated our approach against other existing approaches, using an existing benchmark suite and found that our approach performs better than comparable approaches for queries that are not highly selective.