Department of Computer Science and Technology

Technical reports

The dual-level validation concurrency control method

Zhixue Wu, Ken Moody, Jean Bacon

June 1993, 24 pages

DOI: 10.48456/tr-301


Atomic data types permit maximum concurrency among transations by exploiting the semantics of object operations. Concurrency control is needed to ensure both object level atomicity and transaction level atomicity. It must be possible to regard each operation on an object as elementary. Recovery methods for transactions which are based on atomic objects must take into account that partial results of a transaction might be seen by other transactions.

This paper presents, formalises and verifies a protocol called the dual-level validation method which can be used to provide atomicity for atomic data types. It is optimistic and has a number of advantages over previous methods. It permits maximum concurrency at the low level by allowing non-conflicting operations to be scheduled concurrently. It allows applications to cope with very large objects by supporting multi-granularity shadowing. Transaction recovery is simple to implement. The method performs well, particularly when different transactions are unlikely to access the same (sub)objects concurrently. Finally, it is well suited to a distributed environment since validation and commit are not implemented atomically.

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BibTeX record

  author =	 {Wu, Zhixue and Moody, Ken and Bacon, Jean},
  title = 	 {{The dual-level validation concurrency control method}},
  year = 	 1993,
  month = 	 jun,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-301},
  number = 	 {UCAM-CL-TR-301}