Showing papers on "Multiversion concurrency control published in 1979"

Concurrency Control and Consistency of Multiple Copies of Data in Distributed Ingres

Abstract: This paper contains algorithms for ensuring the consistency of a distributed relational data base subject to multiple, concurrent updates. Also included are mechanisms to correctly update multiple copies of objects and to continue operation when less than all machines in the network are operational. Together with [4] and [12], this paper constitutes the significant portions of the design for a distributed data base version of INGRES.

An optimality theory of concurrency control for databases

Abstract: A concurrency control mechanism (or a scheduler) is the component of a database system that safeguards the consistency of the database in the presence of interleaved accesses and update requests. We formally show that the performance of a scheduler, i.e., the amount of parallelism that it supports, depends explicitly upon the amount of information that is available to the scheduler. We point out that most previous work on concurrency control is simply concerned with specific points of this basic trade-off between performance and information. In fact, several of these approaches are shown to be optimal for the amount of information that they use.

On Optimistic Methods For Concurrency Control

Abstract: Most current approaches to concurrency control in database systems rely on locking of data objects as a control mechanism. In this paper, two families of non-locking concurrency controls are presented. The methods used are "optimistic" in the sense that they rely mainly on transaction backup as a control mechanism, "hoping" that conflicts between transactions will not occur. Applications where these methods should be more efficient than locking are discussed.

Correctness of concurrency control and implications in distributed databases

Abstract: In this paper we report our preliminary re sults in the correctness of concurrency control and we outline a new approach to concurrency control. First, we derive necessary and sufficient condition for the serializability of concurrent execution of transactions, regardless of the underlying mech anism (i. e. locking or time stamps) controlling such execution. We then outline a proposal for a new approach to concurrency control which is motivated by the results presented in the first part of the paper. The approach is based on detection of nonserializable actions and subsequent recovery rather than the prevention or avoidance methods which are used by existing concurrency control mechanisms.

A hierarchical structure for concurrency control in a distributed database system

Abstract: This paper focuses on the concurrency control problem for a distributed database system. A new control philosophy called hierarchical processing structure is proposed. Two different types of the consistency are clearly defined, and the hierarchical processing structure is derived from these consistency types. This structure provides the following features;1) The centralization of processing load on a particular site can be avoided.2) Two distinct types of updating mechanism are defined according to two aspects of data consistency.3) A comprehensible philosophy for the concurrency control is established.