(m, k)-Firm Constraints and Derived Data Management for
the QoS Enhancement in Distributed Real-Time DBMS
Malek Ben Salem1, Emna Bouazizi1,2, Claude Duvallet3, and Rafik Bouaziz1
1Higher Institute of
Computer Science and Multimedia, Sfax
University, Tunisia
2College of Computer Science
and Engineering, Jeddah University, Jeddah, Saudi Arabia
3Normandie Univ, UNIHAVRE,
LITIS, 76600 Le Havre, France
Abstract: Distributed Real-Time DBMS (DRTDBMS) is a collection
of Real-Time DataBase Management Systems (RTDBMS) running on sites connected
together via communication's networks for transaction processing. This system
is characterized by the data distribution and the unpredictable transactions.
In addition, in this system, the presence of several sites raises the problem
of the unbalanced load between those nodes. In order to enhance the performance
of DRTDBMS with taking into account those problems, Quality of Service (QoS)
based approaches are the most appropriate. Distributed Feedback Scheduling
Control Architecture (DFCSA) is proposed for managing the QoS in this system.
In DRTDBMS, the results produced in time with less precision are sometimes
preferable than exact results obtained in delay, inaccuracy can be tolerated.
In order to take this assertion, in this paper, we extend the DFCSA by using
the (m, k)-firm constraints, which take into account the imprecise results,
using three data replication policies. The obtained architecture is called (m, k)-firm-User-DFCS.
The second contribution consists of taking into account the real-time derived
data on (m, k)-firm-User-DFCS architecture, always, using three data
replication policies. The obtained architecture is called Derived Data
Management (DDM)-(m, k)-firm-User-DFCS. Then, we are focusing on
two ways of service optimization in DRTDBMS. We are interested in (1) the space
optimization in which we propose to apply three replication data policies, and
(2) the QoS optimization in which we propose to take into account the real-time
derived data and (m, k)-firm constraints.
Keywords: Software DRTDBMS, QoS management, feedback
control scheduling, (m, k)-firm constraints, derived data.