Section: New Results

XML Query Optimization

Participants : Ioana Manolescu, Martin Goodfellow, Konstantinos Karanasos, Spyros Zoupanos.

XML storage and query optimization

Work in this area is winding down. The main results concern contributions to the Springer Encyclopedia of Database Systems, published in 2009. Our contribution in this area include an algebra for XML query processing [44] , a survey of XML storage techniques in relational databases [41] .

Performance evaluation methodology

Performance evaluation is a natural component in many data-oriented works such as those carried on in Gemo. Intense discussion emerged within the international scientific data management community since 2006 as to what is the standard of proof for performance claims made in research papers, and how best to foster rapid prototyping and improvement of research platforms by sharing or at least facilitating the process of experimenting with somebody else's code. Gemo has been at the forefront of this effort, since I. Manolescu has been the first SIGMOD Repeatability chair (2008). This involvement has continued in 2009 where I. Manolescu has been the SIGMOD Repeatability and Workability co-chair (with S. Manegold from CWI Amsterdam). K. Karanasos has participated to the SIGMOD 2009 Repeatability and workability PC. Insights obtained from this effort have been made available to the community via a joint paper [51] and a tutorial [26] .

Incremental maintenance of XML materialized view

Work has started together with A. Bonifati on the issue of incrementally maintaining tree pattern materialized views. The visit of M. Goodfellow in our group is centered around this topic.