SoIT's News, Issue 3 2008

Database break-through wins ACM-SIGMOD Best Paper Award

Cutting-edge database research at the School of IT has been recognised with the Best Paper Award at the Association for Computing Machinery’s SIGMOD International Conference on Management of Data. School of IT alumnus (and current PhD student) Michael Cahill has been investigating an innovative change to the internals of database management systems that will have an impact on commercial databases around the world. ACM-SIGMOD is considered the most important international conference in the field of databases, and the award is one of the highest honours bestowed on researchers in the area.

Many popular database systems allow operations to run in parallel using a technique known as Snapshot Isolation. Software developers reason about databases as if operations are run one after the other, but Snapshot Isolation does not provide the strong guarantees that make their reasoning valid. An example from the award winning paper is of a hospital rostering system: if two doctors rostered on in a shift try to reschedule at the same time, databases using Snapshot Isolation could leave the hospital with no staff.

Michael’s paper suggests some changes to the Snapshot Isolation algorithm that allow operations to run in parallel but avoids situations where the data consistency is violated. In the hospital example, only one of the doctors would be able to reschedule.

This work has the potential for significant impact on commercial databases and applications in fields ranging from scheduling, online bookings and financial transactions.

Industry is showing a keen interest in the research. Dr Dave Lomet, Head of the Database Research group at Microsoft Research in Redmond says “More concurrency - plus serializable transactions! This is a technology with great promise that could change the industry.”

Michael graduated from The University of Sydney in 1997 with BSc Honours and the University Medal for Computer Science, and has since worked in the IT industry in both Australia and overseas. He is currently the Principal Software Engineer at Oracle Berkeley DB and is completing his PhD in the School of IT with Associate Professor Alan Fekete and Dr Uwe Roehm. This paper will form the core of his thesis.

ACM SIGMOD is the Association for Computing Machinery’s Special Interest Group on Management of Data, which specializes in large-scale data management problems and databases. The annual SIGMOD conference, which began in 1975, was held in Vancouver, Canada in June 2008.

Photo: L-R Dr Uwe Roehm, Michael Cahill and Associate Professor Alan Fekete