Showing papers on "Concurrency control published in 1977"
TL;DR: A dynamic index, called an interval hierarchy, is described, which supports several important retrieval operations on files of simple conjunctive predicates, and search and maintenance algorithms for interval hierarchies are given.
Abstract: Predicates are used extensively in modern database systems for purposes ranging from user specification of associative accesses to data, to user-invisible system control functions such as concurrency control and data distribution. Collections of predicates, or predicate files, must be maintained and accessed efficiently. This paper describes a dynamic index, called an interval hierarchy, which supports several important retrieval operations on files of simple conjunctive predicates. Search and maintenance algorithms for interval hierarchies are given. For a file of n predicates, typical of the kind expected in practice, these algorithms require time equal to O(log n).
17 citations
15 Dec 1977
TL;DR: SDD-1 permits data to be stored redundantly at several database sites in order to enhance the reliability and responsiveness of the system and to facilitate upwards scaling of system capacity.
Abstract: : SDD-1, a System for Distributed Databases, is a distributed database system being developed by CCA. SDD-1 permits data to be stored redundantly at several database sites in order to enhance the reliability and responsiveness of the system and to facilitate upwards scaling of system capacity. This paper describes the algorithm used by SDD-1 for updating that is stored redundantly.
15 citations
Proceedings Article•
01 Jan 1977
TL;DR: This paper presents designs for several distributed concurrency controls and demonstrates that they work correctly and investigates some of the implications of global consistency of a distributed database and discusses phenomena that can prevent termination of application programs.
11 citations
01 Jan 1977
TL;DR: This chapter contributes to the 10th anniversary symposium of the Computer Science Department at Carnegie-Mellon University by looking at two old problems in concurrent processes in a new light, that of restricting the order in which concurrent processes may operate on shared objects.
Abstract: This chapter contributes to the 10th anniversary symposium of the Computer Science Department at Carnegie-Mellon University by looking at two old problems in concurrent processes in a new light. The first problem is that of restricting the order in which concurrent processes may operate on shared objects. We show how such restrictions can be stated as path expressions. The second problem is that of deadlock states. An O ( mn log n ) deadlock detection algorithm is presented, which is based on the heapsort algorithm.
7 citations
03 Aug 1977
TL;DR: A dynamic index is described, called an interval hierarchy, which supports several important retrieval operations on files of simple conjunctive predicates, and search and maintenance algorithms for interval hierarchies are given.
Abstract: Predicates are used extensively in modern data base systems, for purposes ranging from user specification of associative accesses to data, to user-invisible system control functions such as concurrency control and data distribution. Collections of predicates, or predicate files, must be maintained and accessed efficiently. This paper describes a dynamic index, called an interval hierarchy, which supports several important retrieval operations on files of simple conjunctive predicates. Search and maintenance algorithms for interval hierarchies are given. For a file of n predicates, typical of the kind expected in practice, these algorithms require time equal to O(log n).
5 citations