A Comparison of Alternative Encoding Mechanisms for Web Services

A web service is a modular application that is published, advertised, discovered, and invoked across a network, i.e., an intranet or the Internet. It is based on a “software-as-services” model and may participate as a component of other web services and applications. Binary and XML are two popular encoding/decoding mechanisms for network messages. Binary encoding is used when performance is critical and XML encoding is employed when interoperability with other web services and applications is essential. With each, one may employ compression to reduce message size prior to its transmission across the network. These decisions have a significant impact on response time and throughput. This paper reports on our experiences with a decision support benchmark, TPC-H, using these alternatives on different hardware platforms. We focus on queries and make the following observations. First, compression reduces the message size and enhances the throughput of a shared network. With XML, we present numbers from XMill, a compression technique that employs XML semantics. For queries that produce more than one megabyte of XML data, XMill compressed XML messages are almost always smaller than the Zip compressed Binary messages. While this improves the throughput of a networked environment with a fixed bandwidth, the response time of XMill compressed messages are at times twice slower than Zip compressed Binary messages. The processor speed has a significant impact on the observed response times.