Hierarchical Database Decomposition: A Technique for Database Concurrency Control.

摘要

A generally accepted criterion for correctness of a concurrency control algorithm is the criterion of serializability of transactions. The classical approaches to enforcing serializability are the two-phase locking technique and the timestamp ordering technique. Either approach requires that a read operation from a transaction be registered (in the form of either a read time stamp or a read lock), so that a write operation from a concurrent transaction will not interfere improperly with the read operation. However, setting a lock or leaving a timestamp with a data element is an expensive operation. The purpose of the current research is to seek ways to reduce the overhead of synchronizing certain types of read accesses, and at the same time achieving the goal of serializability. To this end, a hierarchical structure is proposed here as the means for analyzing opportunities of reducing concurrency overhead in a database application.