Load-Balancing Remote Spatial Join Queries in a Spatial GRID

The explosive growth of spatial data worldwide coupled with the emergence of GRID computing provides a strong motivation for designing a spatial GRID which allows transparent access to geographically distributed data. While different types of queries may be issued from any node in such a spatial GRID for retrieving the data stored at other (remote) nodes in the GRID, this paper specifically addresses spatial join queries. Incidentally, skewed user access patterns may cause a disproportionately large number of spatial join queries to be directed to a few ‘hot’ nodes, thereby resulting in severe load imbalance and consequently increased user response times. Hence, an effective load-balancing strategy becomes a necessity to prevent performance degradation. In this regard, the main contributions of our proposal are as follows. First, we present a dynamic data placement strategy involving online data replication in GRIDs, the objective being to bring the data closer to the node from which it is frequently queried. Second, we propose a novel load-balancing strategy for speeding up spatial joins in GRID environments. Our performance evaluation demonstrates the effectiveness of our proposed approach in reducing the response times of spatial joins in GRIDs.