The BANG file: A new kind of grid file

Abstract

A new multi-dimensional file structure has been developed in the course of a project to devise ways of improving the support for interactive queries to database and knowledge bases. Christened the 'BANG' file-a Balanced And Nested Grid-the new structure is of the 'grid file' type, but is fundamentally different from previous grid file designs in that it does not share their common underlying properties. It has a tree-structured directory which has the self-balancing property of a B-Tree and which, in contrast to previous designs, always expands at the same rate as the data, whatever the form of the data distribution. Its partitioning strategy both accurately reflects the clustering of points in the data space, and is flexible enough to adapt gracefully to changes in the distribution.