Dynamic object offloading in Web services

In several application contexts, Web Services adoption is limited due to performance issues. Design methods often propose the adoption of coarse-grained interfaces to reduce the number of interactions between clients and servers. This is an important design concern since marshaling and transferring small parts of complex business objects might entail sensible delays, especially in high latency networks. Nevertheless, transferring large data in coarse-grained interactions might bring useless data on the client side, whereas a small part of the transferred object is used. To reduce data transfers, in addition to well-known techniques based on XML compression, a possible approach is considering a finer granularity at data level: results produced by Web services invocations could be transferred to the client by using incremental loading. However, existing Web service technology does not provide run-time infrastructures with an adequate support for lazy serialization. In addition, pure lazy serialization could incur in high overheads due to many interactions, especially in wide area networks. This paper presents a novel approach to extend existing Web services run-time supports with dynamic offloading capabilities based on an adaptive strategy that allows servers to learn clients behaviors at runtime. By exploiting this approach, service based applications can improve their performances, as experimental results show, without any invasive change to existing Web services and clients.