Serializability with constraints

  • Authors:

  • Toshihide Ibaraki;Tiko Kameda;Toshimi Minoura

  • Affiliations:

  • Department of Applied Mathematics and Physics, Kyoto University, Kyoto, 606 Japan;School of Computing Science, Simon Fraser University, Burnaby, B.C., Canada V5A 1S6;Department of Computer Science, Oregon State University, Corvallis, OR

  • Venue:
  • ACM Transactions on Database Systems (TODS)
  • Year:
  • 1987

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Abstract

This paper deals with the serializability theory for single-version and multiversion database systems. We first introduce the concept of disjoint-interval topological sort (DITS, for short) of an arc-labeled directed acyclic graph. It is shown that a history is serializable if and only if its transaction IO graph has a DITS. We then define several subclasses of serializable histories, based on the constraints imposed by write-write, write-read, read-write, or read-read conflicts, and investigate inclusion relationships among them. In terms of DITS, we give a sufficient condition for a class of serializable histories to be polynomially recognizable, which is then used to show that a new class of histories, named WRW, can be recognized in polynomial time. We also present NP-completeness results for the problem of testing membership in some other classes.In the second half of this paper, we extend these results to multiversion database systems. The inclusion relationships among multiversion classes defined by constraints, such as write-write and write-read, are investigated. One such class coincides with class DMVSR, introduced by Papadimitriou and Kanellakis, and gives a simple characterization of this class. It is shown that for most constraints, multiversion classes properly contain the corresponding single-version classes. Complexity results for the membership testing are also discussed.