Authors:
Mourad Kaddes
1
;
Laurent Amanton
2
;
Alexandre Berred
2
;
Bruno Sadeg
2
and
Majed Abdouli
3
Affiliations:
1
Le Havre University and Sfax University, France
;
2
Le Havre University, France
;
3
Sfax University, Tunisia
Keyword(s):
Real-time Database System, Transaction Processing, Scheduling Policy, Success Ratio, Transaction Importance.
Related
Ontology
Subjects/Areas/Topics:
Agents
;
Artificial Intelligence
;
Bioinformatics
;
Biomedical Engineering
;
Databases and Information Systems Integration
;
Enterprise Information Systems
;
Information Systems Analysis and Specification
;
Methodologies and Technologies
;
Operational Research
;
Performance Evaluation and Benchmarking
;
Query Languages and Query Processing
;
Simulation
Abstract:
Scheduling transactions in real-time database systems (RTDBSs) is more complex than scheduling tasks in real-time systems. In fact, the RTDBS must guarantee the database logical consistency, on one hand, and it must schedule the transactions in order to meet their deadlines, on the other hand. The main policy used
to schedule transactions in RTDBSs is Earliest Deadline First (EDF). However, it is well-known that EDF is not efficient for scheduling transactions in overload conditions. Consequently, different scheduling protocols: AED, AEVD, APP, AEDF-Co, GEDF... were proposed to improve the system performances in firm RTDBSs, i.e. late transactions are considered useless. Generalized Earliest Deadline First (GEDF) is a new scheduling protocol in which transaction priority is assigned according to both deadlines and a parameter, called SPriority, which expresses the importance of transactions. In this paper, an RTDBSs analysis is presented. The accuracy of GEDF scheduling policy and th
e influence of database workload on the system performances is investigated.
This study enabled us to describe the complete behavior of the transaction success ratio. Moreover, based on intensive simulations, we have derived the optimal values of the system parameters which improve the success ratio without modifying GEDF protocol.
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