Multiversion Concurrency Control Research Articles

Multi-version concurrency control scheme for a database system

A concurrency control scheme using multiple versions of data objects is presented which allows increased concurrency. The scheme grants an appropriate version to each read request. Transactions issuing write requests which might destroy database integrity are aborted. It is precisely stated when old versions can be discarded and how to eliminate the effects of aborted transactions is described in detail. The scheduler outputs only ( multi-version) ww-serializable histories which preserve database consistency. It is shown that any “ D-serializable” history of Papadimitriou ( J. Assoc. Comput. Mach. 26 (4) (1979), 631–653) (or “conflict-preserving serializable log” of Bernstein et al., IEEE Trans. Software Engrg. SE-5 (3) (1979), 203–216) is ww-serializable.

Multiversion concurrency control—theory and algorithms

Concurrency control is the activity of synchronizing operations issued by concurrently executing programs on a shared database. The goal is to produce an execution that has the same effect as a serial (noninterleaved) one. In a multiversion database system, each write on a data item produces a new copy (or version ) of that data item. This paper presents a theory for analyzing the correctness of concurrency control algorithms for multiversion database systems. We use the theory to analyze some new algorithms and some previously published ones.