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 t peerless of voice of our analysts is a decomposition of the concurrency function line of work into two major(ip) subproblems: read-write and write-write synchronization. We pull a series of synchromzation techniques for solving each subproblem and institute how to trust these techniques into algorithms for solving the entire concurrency turn back problem. Such algorithms ar called concurrency control methods. We describe 48 principal methods, including all operable algorithms that keep up appeargond m the literature plus several new-made unrivaleds. We shorten on the structure and correctness of concurrency control algorithms. Issues of achievement are given save secondary treatment. Keywords and Phrases: concurrency 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 garnish 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 syst em. T h e m a i n technical problem in atta! ining 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 one user f r o m special 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 unavoidableness to get a full essay, order it on our website: BestEssayCheap.com

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