Recently, as applications of web service have been taken more and more widely, there are increasingly high requirements on services. A single simple web service is often not able to achieve the user's requirements, hence an optimized composition of a number of small granular services is needed, through which we can not only enhance the reusability of sen/ices, but also provide sen/ices based on the users' changing requirements. Web service composition is defined as an orchestration of multiple web services into a single composite web service. Web service composition is done in three ways such as static web service composition, dynamic web service composition, semi dynamic web service composition. A composition is called static, if all the web sen/ices required to create an application have to be discovered before launching the whole application. But the dynamic web service composition is done on the fly. In static composition the composite sets are more volatile since change of information is more as the service providers revise the services with new versions. In the dynamic composition the executing workflow is tested to check whether the query adopts the changes done by service providers according to their revised QoS parameter values.

In this paper, we have done a study on the behavior of the static and dynamic web service compositions with different quality parameters for a specific scenario. For dynamic composition, a composition schema is generated and approved only after checking the feasibility based on the quality of services in the given solution space. Statistical composition and dynamic composition (with and without feasibility checking) performance are tested in the application spatial information system. The success rate and failure rates for both of these compositions are calculated, analyzed and reported.

Key words: Web service composition, Static Vs Dynamic composition, Composition feasibility