ISSN:
1573-7470
Source:
Springer Online Journal Archives 1860-2000
Topics:
Computer Science
,
Mathematics
Notes:
Abstract A new correctness criterion for schedules of update transactions is proposed, which captures users' intended changes to the database. This is motivated by the observation that traditional serializability may lead to anomalies by not taking into account semantics related to such intended changes. The alternate criterion —goal-correctness — is orthogonal to serializability, and is based on realizing goals associated with each transaction. The problems involved in goal-oriented concurrency control are first identified in a general framework. The analysis suggests that this approach is practical only for restricted transaction languages where goals can be inferred and manipulated efficiently. One such language is then considered, capturing a class of updates of practical interest. For this language, it is shown that goal-oriented concurrency control is tractable and compares favorably to serializability with respect to complexity: testing goal-correctness takes polynomial time, while testing serializability is NP-complete. The set of schedules which are correct with respect to the two criteria are incomparable. Thus, goal-correctness may allow increased concurrency. The results highlight the feasibility and advantages of goal-oriented concurrency control in restricted frameworks. The paper also discusses the dynamic aspects of goal-oriented concurrency control; in particular, an optimistic approach to the dynamic generation of goal-correct schedules is presented.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01556355
