Master Thesis - Past Projects - Abstract
Concurrency Control in a Configurable Component-Based Real-Time Database
The increased demand for efficient data management in real-time systems
and the increasing need for having configurable real-time software has
lead to the development of a configurable COMponent-based Embedded
real-Time database (COMET). COMET is designed using AspeCtual
COmponent-based Real-time system Development (ACCORD), which supports
decomposition of real-time software into aspects and components. Hence,
COMET is designed to consist of aspects and components. COMET has a
library of components that allow configuring a system with basic
database functionality, without support for concurrency.
The goal of this work is to extend the COMET library, with focus on
enabling concurrency. We present the design and implementation of
aspects that can be woven into the existing COMET components to produce
COMET configurations that support concurrency.
Three concurrency control algorithms have been designed and implemented:
high priority 2-phase locking with similarity, optimistic divergence
control and GUARD-link. High priority 2-phase locking with similarity
and optimistic divergence control are concurrency control methods that
control access to tuples in the database. Both methods are based on
locks, which makes their design similar. They are implemented as aspects
that crosscut large parts of the components in the COMET library.
GUARD-link is an index concurrency control method. It consists of an
admission controller and a B-link tree index structure. The admission
controller is implemented as an aspect and the B-link tree as a
replacement to the existing indexing component.
By extending the COMET library with these aspects and the replacement
indexing component, several new configurations of COMET become possible,
all of which support concurrency.
Keywords: concurrency control, real-time databases, aspect-oriented software development, real-time systems, aspects, components, similarity- based concurrency control, index concurrency control
Author(s): Kristoffer Erlandsson
Contact: Jörgen Hansson
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