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Weak consistency of read-only transactions: A tool to improve concurrency in heterogeneous locking protocols

  • R. C. Hansdah
  • L. M. Patnaik
Session 5 Database Theory
Part of the Lecture Notes in Computer Science book series (LNCS, volume 287)

Abstract

Three different types of consistencies, viz., semiweak, weak, and strong, of a read-only transaction in a schedule s of a set T of transactions are defined and these are compared with the existing notions of consistencies of a read-only transaction in a schedule. We present a technique that enables a user to control the consistency of a read-only transaction in heterogeneous locking protocols. Since the weak consistency of a read-only transaction improves concurrency in heterogeneous locking protocols, the users can help to improve concurrency in heterogeneous locking protocols by supplying the consistency requirements of read-only transactions. A heterogeneous locking protocol P' derived from a locking protocol P that uses exclusive mode locks only and ensures serializability need not be deadlock-free. We present a sufficient condition that ensures the deadlock-freeness of P′, when P is deadlock-free and all the read-only transactions in P′ are two phase.

Keywords

Data Item Database Management System Strong Consistency Partial Schedule Weak Consistency 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1987

Authors and Affiliations

  • R. C. Hansdah
    • 1
  • L. M. Patnaik
    • 1
  1. 1.Department of Computer Science and AutomationIndian Institute of ScienceBangaloreIndia

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