System level concurrency control for distributed database systems

Abstract

A distributed database system is one in which the database is spread among several sites and application programs move from site to site to access and update the data they need. The concurrency control is that portion of the system that responds to the read and write requests of the application programs. Its job is to maintain the global consistency of the distributed database while ensuring that the termination of the application programs is not prevented by phenomena such as deadlock. We assume each individual site has its own local concurrency control which responds to requests at that site and can only communicate with concurrency controls at other sites when an application program moves from site to site, terminates, or aborts. This paper presents designs for several distributed concurrency controls and demonstrates that they work correctly. It also investigates some of the implications of global consistency of a distributed database and discusses phenomena that can prevent termination of application programs. © 2009 Springer Netherlands.