Exploiting Dynamic Deployment in a Distributed Query Processor for the Grid

Grid computing has enabled users to perform computationally expensive applications on distributed resources acquired dynamically. It has also allowed users to combine data and analysis components into new applications from sites all over the world. Often such distributed data is structured, and an established way of structuring computations is found in distributed query processing. The established Grid tools like OGSA-DAI and OGSA-DQP provide respectively a common interface to different underlying databases and a way of expressing a global schema which unites the distributed resources and supports evaluation of declarative queries in distributed fashion. While Grid computing offers these significant benefits to a user, it also incurs the difficulties that arise through distribution, especially at wide area scale, on non-dedicated resources. Computation and communication costs can both be significant and vary significantly. In such contexts, a range of techniques for dynamic adaptation of distributed queries need to be employed in order to ensure reasonably efficient execution. DynaSOAr is an infrastructure for dynamically deploying we

Exploiting Dynamic Deployment in a Distributed Query Processor for the Grid

The adoption of the "Web Services" model for building a Grid framework created a considerable shift from the original concept of Grid which was based on "distributed job scheduling". The requirement for the access and integration of heterogeneous data resources over the Grid, and the advances in service-oriented data access standards led to the development of a service-oriented distributed query processor, which forms the basis of this thesis. The adoption of service-orientation raised the need for a framework which would allow demand-driven deployment of Web Services on available resources. Research into such concepts led to the development of DynaSOAr, a framework which proposed an alternative approach to distributed job scheduling by focussing entirely on the concept of services, rather than the more traditional jobs. DynaSOAr allows services to be deployed on demand to meet changing performance requirements and exploits the advances made in virtualization technologies to support the deployment of services and databases