Concurrency Control Using Basic Timestamp Ordering (Thomas Write Rule)

Abstract

Concurrency control is the activity of coordinating concurrent accesses to a database in a multiuser database management system (DBMS). Concurrency control permits users to access a database in a multi-programmed fashion while preserving the illusion that each user is executing alone on a dedicated system. The main technical difficulty in attaining this goal is to prevent database updates performed by one user from interfering with database retrievals and updates performed by another. The concurrency control problem is exacerbated in a distributed DBMS because user may access data stored in many different computers in a distributed system and a concurrency control mechanism at one computer cannot instantaneously know about interactions at other computers [7]. In this paper, we present the concurrency control of distributed transactions for centralized database by using Basic Timestamp Ordering (Thomas Write Rule).