Parallel Processing
Parallelism plays a significant role in processing massive databases. Teradata pioneered some of the key technology. All major vendors of database management systems now offer data partitioning and parallel query processing technology. The article by Dewitt and Gray provides an overview of this area. One interesting technique relevant to the read-only environment of decision support systems is that of piggybacking scans requested by multiple queries (used in Redbrick). Piggybacking scan reduces the total work as well as response time by overlapping scans of multiple concurrent requests.