Concurrency Control in the Interpolation-Based Grid File

The problem of supporting concurrent operations in Interpolation-Based Grid Files is studied. A systematic method for detecting conflict between processes is defined based on the organizational properties of this type of files. One important characteristic of these structures is the dynamic partitioning of the data space into regions and assignment of a unique identifier to each region. This identifier acts then as a surrogate for the region and its spatial properties. High process throughput is achieved by optimizing the number of locked regions. We show that only one or two locks are required in general and the probability that three locks become necessary is negligible. Algorithms to search for, to insert and delete data elements are presented and shown to be correct, deadlock free, and non-preemptive based on the restrictions imposed on the locking order and the reachability mechanism. Furthermore, we present a compression procedure that provides storage maintenance of the data structure. In our scheme, all processes readers, inserters, deleters and compressors can overtake each other.