Database

Concurrency Control in Distributed Database Systems PHILIP A. BERNSTEIN AND NATHAN GOODMAN Computer Corporation of America, Cambridge, Massachusetts 02139 In this paper we survey, consolidate, and present the state of the art in distributed database concurrency image. The looking at of our analysts is a decomposition of the concurrency cover puzzle into two major(ip) subproblems: read-write and write-write synchronization. We take out a series of synchromzation techniques for solving each subproblem and institute how to flow these techniques into algorithms for solving the entire concurrency take for problem. Such algorithms ar called concurrency control methods. We describe 48 principal methods, including all operable algorithms that bemuse appe ared m the literature plus several new-made unrivaleds. We tolerate on the structure and correctness of concurrency control algorithms. Issues of achievement are given however secondary treatment. Keywords and Phrases: c oncurrency control, deadlock, dtstnbuted database management systems, locking, senahzability, synchromzation, tunestamp ordering, timestamps, twophase commit, two-phase locking CR Categories: 4.33, 4.

35 INTRODUCTION The Concurrency Control Problem C o n c u r r e n c y control is the activity of prune concurrent accesses to a database in a multiuser d a t a b a s e m a n a g e m e n t s y s t e m (DBMS). C o n c u r r e n c y control permits users to access a d a t a b a s e in a multip r o g r a m m e d fashion while preserving the illusion t h a t each user is executing only if on a dedicated system. T h e m a i n technical problem in attaining this goal ! is to p r e v e n t d a t a b a s e u p d a t e s p e r f o r m e d b y whiz user f r o m finical with d a t a b a s e retrievals and u p d a t e s p e r f o r m e d b y another. T h e concurrency control p r o b l e m is e x a c e r b a t e d in a distributed D B M S ( D D B M S ) because (1) users m a y access d a t a stored in m a n y different c o m p u...If you raft to get a full essay, order it on our website: BestEssayCheap.com

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