[26 May 2014] A bachelor student at RTSLAB was awarded the best thesis
award from IDA - Simon Andersson. more ...
[31 May 2012] A masters student at RTSLAB was awarded the best thesis
award from IDA - Ulf Magnusson. more ...
[27 February 2008] A masters student at RTSLAB was awarded the best thesis
award from IDA - Johan Sigholm. more ...
[03 March 2004] A masters student at RTSLAB was awarded the best thesis
award from IDA - Tobias Chyssler. more ...
[01 Jul 2003] For second year in a row a masters student at RTSLAB was awarded the best thesis
award from SNART - Mehdi Amirijoo. more ...
Master Thesis - Past Projects - Abstract
Data Versioning in a Real-Time Data Repository
Most engines in modern cars are controlled by a computer called Engine
Control Unit (ECU). The software running on the ECU can be divided
into two parts: functionality for controlling the engine and
functionality for diagnosing faults in the engine. In order to deal
with increasing complexity of the software a database has been
implemented as part of a previous project. As the diagnosis is not as
time-critical as the functionality for controlling the engine, it is
run with low priority. This makes it hard to guarantee relative
consistency for the data used by the diagnosis.
Previous work has shown that multiple versions of data can help
increase both temporal consistency of data and performance of the
system. This thesis presents implementation and performance evaluation
of two concurrency control algorithms, optimistic concurrency control
(OCC) and multi-version timestamp ordering validity bounds
(MVTO-VB). MVTO-VB utilizes multiple versions of data in order to
guarantee relative consistency.
The performance evaluation compares the algorithms in conjunction with
two different on-demand updating algorithms: On-Demand Depth First
Traversal (ODDFT) and On-Demand Top-Bottom (ODTB). It shows that in
conjunction with ODDFT, MVTO-VB obtains the best performance among the
algorithms. In conjunction with ODTB, a variant of OCC obtains the
best performance and MVTO-VB the worst.
Keywords: real-time databases, concurrency control, relative consistency
Author(s): Hugo Hallqvist
Contact: Jörgen Hansson
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