Adaptive parallelization of queries to data providing web service operations

Abstract

A data providing web service operation returns a collection of objects for given parameters without any side effects. The Web Service MEDiator (WSMED) system automatically provides relational views of any data providing web service operations by reading their WSDL documents. These views are queried with SQL. In an execution plan, a call to a data providing web service operation may depend on the results from other web service operation calls. In other cases, different web service calls are independent of each other and can be called in any order. To parallelize and speed up both dependent and independent web service operation calls, WSMED has been extended with the adaptive operator PAP. It incrementally parallelizes calls to web service operations until no significant performance improvement is measured. The performance of PAP is evaluated using publicly available web services. The operator substantially improves the query performance without knowing the cost of calling a web service operation and without extensive memory usage. © 2012 Springer-Verlag Berlin Heidelberg.