Dynamic granular locking approach to phantom protection in R-trees

Over the last decade (1988-98), the R tree has emerged as one of the most robust multidimensional access methods. However, before the R tree can be integrated as an access method to a commercial strength database management system, efficient techniques to provide transactional access to data via R trees need to be developed. Concurrent access to data through a multidimensional data structure introduces the problem of protecting ranges specified in the retrieval from phantom insertions and deletions (the phantom problem). Existing approaches to phantom protection in B trees (namely, key range locking) cannot be applied to multidimensional data structures since they rely on a total order over the key space on which the B tree is designed. The paper presents a dynamic granular locking approach to phantom protection in R trees. To the best of our knowledge, the paper provides the first solution to the phantom problem in multidimensional access methods based on granular locking.