A Simulation-Based Study on the Concurrent Execution of Rules in a Database Environment

doi:10.1006/jpdc.1994.1003

Journal of Parallel and Distributed Computing

Volume 20, Issue 1, January 1994, Pages 20-42

https://doi.org/10.1006/jpdc.1994.1003 Get rights and content

Abstract

We present our research on the concurrent execution of rules in a database environment. Traditionally, the serializability criterion of correctness is defined on the basis of read/write conflicts. With rules, however, the conditions must be true for the actions to execute, and rules must fail when their conditions are no longer true. A different correctness criterion is thus defined on the basis of conflicts between conditions and actions. We develop a locking based protocol and discuss extensions to a conventional transaction manager. One extension is a new lock compatibility matrix which provides greater concurrent access. The second extension is to allow concurrent execution within a transaction. A simulation-based performance study is described. We identify characteristic features of the rules and study their impact on performance. The impact of using the new lock compatibility matrix, the effect of varying the database size and the number of rules executing concurrently, and the effect of skew are studied.

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Cited by (7)

A concurrent rule scheduling algorithm for active rules
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Citation Excerpt :
Whereas the work in [7] was designed for use in the interactive resolution of rule confluence, the IRS algorithm was designed for automatic resolution of confluence. The work in [29] presents research on the concurrent execution of production rules. A production rule consists of a condition and an action with no explicit event.
The use of rules in a distributed environment creates new challenges for the development of active rule execution models. In particular, since a single event can trigger multiple rules that execute over distributed sources of data, it is important to make use of concurrent rule execution whenever possible. This paper presents the details of the integration rule scheduling (IRS) algorithm. Integration rules are active database rules that are used for component integration in a distributed environment. The IRS algorithm identifies rule conflicts for multiple rules triggered by the same event through static, compile-time analysis of the read and write sets of each rule. A unique aspect of the algorithm is that the conflict analysis includes the effects of nested rule execution that occurs as a result of using an execution model with an immediate coupling mode. The algorithm therefore identifies conflicts that may occur as a result of the concurrent execution of different rule triggering sequences. The rules are then formed into a priority graph before execution, defining the order in which rules triggered by the same event should be processed. Rules with the same priority can be executed concurrently. The IRS algorithm guarantees confluence in the final state of the rule execution. The IRS algorithm is applicable for rule scheduling in both distributed and centralized rule execution environments.
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Regular ArticleA Simulation-Based Study on the Concurrent Execution of Rules in a Database Environment

Abstract

Regular Article
A Simulation-Based Study on the Concurrent Execution of Rules in a Database Environment