A Status Report on XXL - a Software Infrastructure for Efficient Query Processing.
Michael Cammert, Christoph Heinz, Jürgen Krämer, Martin Schneider, Bernhard Seeger · 2003
XXL is a Java library that contains a rich infrastructure for implementing advanced query processing functionality. The library offers low-level components like access to raw disks as well as high-level ones like a query optimizer. On the intermediate levels, XXL provides a demand-driven cursor algebra, a framework for indexing and a powerful package for supporting aggregation. The library is publicly available under GNU LGPL and comes with a full documentation. 1