Primary copy synchronization for DB-Sharing

摘要

In a database sharing (DB-Sharing) system multiple loosely or closely coupled processors share access to a single set of databases. Such systems promise better availability and linear growth of transaction throughput at equivalent response time compared to single processor database systems. The efficiency of a DB-Sharing system heavily depends on the synchronization technique used for maintaining consistency of the shared data. A promising algorithm is the primary copy approach which will be presented in this paper. We describe the actions of the lock manager in a basic and in a more advanced version. Furthermore, it is shown how the lock managers can be enabled to deal with the so-called buffer invalidation problem that results from the existence of a database buffer in each processor.