next up previous
Next: Transaction Models Up: No Title Previous: No Title

Concurrency Control

The synchronization primitives we have seen so far are not as high-level as we might want them to be since they require programmers to explicitly synchronize, avoid deadlocks, and abort if necessary. Moreover, the high-level constructs such as mointors and path expressions do not give users of a shared object flexibiility in defining the unit of atomicity. We will study here a high-level technique, called concurrency control, which automatically ensures that concurrently interacting users do not execute inconsistent commands on a shared object. A variety of concurrency models defining different notions of consistency have been proposed. These models have been developed in the context of database management systems, operating systems, CAD tools, collaborative software engineering, and collaboration systems. We will focus here on the classical database models and the relatively newer operating system models.


Prasun Dewan
Wed Apr 7 11:52:42 EDT 1999