---

Chair: Michael Kay, Saxonica

Developers have said it: “XML is too slow!”, where “slow” can mean many things including elapsed time, throughput, latency, memory use, and bandwidth consumption. The aim of this one-day symposium is to understand these problems better and to explore and share approaches to solving them.

XML has become so ubiquitous that people are trying to apply it in some very hostile environments. From small mobile and embedded devices to web servers and financial messaging gateways delivering thousands of transactions a second, from terabyte-sized (or infinite) documents to databases that contain zillions of tiny documents, people expect XML to sit quietly in the background and not make a nuisance of itself. Yet some of the current technologies don’t scale particularly well: XSLT and XQuery, for example, can quickly run out of memory as document sizes increase, while the costs of getting XML in and out of databases can bring a system to a halt.

During this symposium, we’ll hear about attempts to tackle the problem at many different levels of the processing stack. Some developers are addressing the XML parsing bottleneck at the hardware level with custom chips or with hardware-assisted techniques such as parallel bitstream processing. Some researchers are looking for ways to compress XML efficiently without sacrificing the ability to perform queries, while others are focusing on the ability to perform queries and transformations in streaming mode. We’ll also hear from a group who believe the problem (and its solution) lies not with the individual component technologies that make up an application, but with the integration technology that binds the components together.

We’ll also hear from someone who has solved the problems in real life, demonstrating that it is possible to build XML-based applications handling very large numbers of documents and a high throughput of queries while offering good response time to users. And that with today’s technologies, not tomorrow’s.

Can performance benefits be achieved without sacrificing XML’s hallmark attractions: validation, flexibility, high level declarative programming? In the best Balisage tradition, our aim is to bring together theory and practice: researchers, product engineers, academics, developers, and users. We all have a lot to learn from each other, and this Symposium offers a unique opportunity to introduce people who think they know some problems to people who think they know some answers, and vice versa.

There is nothing so practical as a good theory

---