Concurrency Control for Spatial Access Method

Jing Dai

Abstract

The concurrency control for spatial access method refers to the techniques providing the serializable operations in multi-user spatial databases. Specifically, the concurrent operations on spatial data should be safely executed and follow the ACID rules (i.e., Atomicity, Consistency, Isolation, and Durability). With concurrency control, multi-user spatial databases can perform the search and update operations correctly without interfering with each other. There are two major concerns in the concurrency control for spatial data access. One is the throughput of concurrent spatial operations. The throughput refers to the number of operations (i.e., search, insertion, and deletion) that are committed within each time unit. It is used to measure the efficiency of the concurrency control protocols. The other concern is to prevent phantom access. Phantom access refers to the update operation that occurs before the commitment and in the ranges of a search/deletion operation, while not reflected in the results of that search/deletion operation. The ability to prevent phantom access can be regarded as a certain level of consistency and isolation in ACID rules.