Structural locking mechanisms and their effect on database management system performance

摘要

Database management systems must provide a concurrency control subsystem to protect database consistency in the presence of concurrent readers and writers. The widely accepted method for realizing such protection in centralized database management systems is through a locking mechanism. The design of a locking mechanism for a relational database management systems presents the developer with a considerable number of new alternatives. This paper discusses some of those alternatives and their tradeoffs. A particular model is then presented which supports these alternatives for relational database management system locking mechanisms. A simulation model is described which was used to provide experimental results investigating these design alternatives. Results from a number of simulation experiments are presented demonstrating the effects on performance realized under different locking mechanism designs and transaction behavior profiles.