Enterprise Database Systems
M¨ lardalen University Press Dissertations a No.21
Data Management in Vehicle Control-Systems
Dag Nystr¨ m o October 2005
Department of Computer Science and Electronics M¨ lardalen University a V¨ ster˚ s, Sweden a a
Copyright c Dag Nystr¨ m, 2005 o E-mail: dag.nystrom@mdh.se ISSN 1651-4238 ISBN 91-88834-97-2 Printed by Arkitektkopia, V¨ ster˚ s, Sweden a a Distribution: M¨ lardalen University Press a
Abstract
As the complexity of vehicle control-systems increases, the amount of information that these systems are intended to handle also increases. This thesis provides concepts relating to real-time database management systems to be used in such control-systems. By integrating a real-time database management system into a vehicle control-system, data management on a higher level of abstraction can be achieved. Current database management concepts are not sufficient for use in vehicles, and new concepts are necessary. A case-study at Volvo Construction Equipment Components AB in Eskilstuna, Sweden presented in this thesis, together with a survey of existing database platforms confirms this. The thesis specifically addresses data access issues by introducing; (i) a data access method, denoted database pointers, which enables data in a real-time database management system to be accessed efficiently. Database pointers, which resemble regular pointers variables, permit individual data elements in the database to be directly pointed out, without risking a violation of the database integrity. (ii) two concurrency-control algorithms, denoted 2V-DBP and 2VDBP-SNAP which enable critical (hard real-time) and non-critical (soft realtime) data accesses to co-exist, without blocking of the hard real-time data accesses or risking unnecessary abortions of soft real-time data accesses. The thesis shows that 2V-DBP significantly outperforms a standard real-time concurrency control algorithm both with respect to lower response-times and minimized abortions. (iii) two
Data Management in Vehicle Control-Systems
Dag Nystr¨ m o October 2005
Department of Computer Science and Electronics M¨ lardalen University a V¨ ster˚ s, Sweden a a
Copyright c Dag Nystr¨ m, 2005 o E-mail: dag.nystrom@mdh.se ISSN 1651-4238 ISBN 91-88834-97-2 Printed by Arkitektkopia, V¨ ster˚ s, Sweden a a Distribution: M¨ lardalen University Press a
Abstract
As the complexity of vehicle control-systems increases, the amount of information that these systems are intended to handle also increases. This thesis provides concepts relating to real-time database management systems to be used in such control-systems. By integrating a real-time database management system into a vehicle control-system, data management on a higher level of abstraction can be achieved. Current database management concepts are not sufficient for use in vehicles, and new concepts are necessary. A case-study at Volvo Construction Equipment Components AB in Eskilstuna, Sweden presented in this thesis, together with a survey of existing database platforms confirms this. The thesis specifically addresses data access issues by introducing; (i) a data access method, denoted database pointers, which enables data in a real-time database management system to be accessed efficiently. Database pointers, which resemble regular pointers variables, permit individual data elements in the database to be directly pointed out, without risking a violation of the database integrity. (ii) two concurrency-control algorithms, denoted 2V-DBP and 2VDBP-SNAP which enable critical (hard real-time) and non-critical (soft realtime) data accesses to co-exist, without blocking of the hard real-time data accesses or risking unnecessary abortions of soft real-time data accesses. The thesis shows that 2V-DBP significantly outperforms a standard real-time concurrency control algorithm both with respect to lower response-times and minimized abortions. (iii) two