Timestamp ordering algorithm of concurrency control for a centralized database system
Concurrency control mechanisms are necessary to preserve database integrity in a multi-user environment. Tne conventional methods use locking-based algorithms to synchronize concurrent transactions so that each user can retrieve or update information correctly in databases. When distributed database systems started being used, the locking-based algorithms became very complicated. Therefore, these conventional methods of concurrency control have been re-examined and the timestamp-based algorithms have been proposed. The main purpose of this research is to investigate these timestamp-based algorithms. Most of the published literature is based on the type of predeclared, atomic transaction processing model. This research is focused on an interactive system which aoes not have the type of predeclared, atomic transaction. Tne comparison to the locking-based algorithms and the advantages and disadvantages are discussed. One of the algorithms has been implemented on a centralized relational database management system for the purpose of exploring its feasibility and for finding out the factors to be considered in choosing concurrency control algorithms. Some comments are made for future research.