Optimizing Database Joins: Cost Models and Benchmarking for CPU and GPU Systems

Optimizing SQL query execution through effective cost models is a critical challenge in database management systems (DBMS). This thesis introduces a modular benchmarking system for cost models, with a pluggable architecture for both cost models and execution engines, enabling comprehensive benchmarking across various scenarios. Accompanied by a...

Building Interactive Text-to-SQL Systems

Natural Language Interfaces for Databases (NLIDBs) offer a way for users to reason about data. It does not require the user to know the data structure, its relations, or familiarity with a query language like SQL. It only requires the use of Natural Language. This thesis focuses on a subset of NLIDBs, namely those with 'plain English' sentences...

Qompliance: Declarative Data-Centric Policy Compliance on SQL-based Data Movements

Data compliance is essential for ensuring that organizations do not run afoul of data protection and privacy legislation. Geographically distributed data is an especially relevant topic because of recent developments in cross-border data protection agreements between the United States and the European Union. We introduce Qompliance, a novel...

A Static-Based Approach to Detect SQL Semantic Bugs

While SQL engines are now capable of detecting a large number of syntactic mistakes, most often semantic errors are not detected, which can lead to serious performance issues or even security vulnerabilities being introduced in the system. This thesis proposes a set of 25 validated heuristics together with a new rule-based static analysis tool...

Transparently Accelerating Spark SQL Code on Computing Hardware

Through new digital business models, the importance of big data analytics continuously grows. Initially, data analytics clusters were mainly bounded by the throughput of network links and the performance of I/O operations. With current hardware development, this has changed, and often the performance of CPUs and memory access became the new...

Automated FPGA Hardware Synthesis for High-Throughput Big Data Filtering and Transformation: An SQL query transpiler targeting Vivado HLS C++ tools for high-level stream transformation and filtering on FPGAs using Apache Arrow.

Despite its advantages in performance and control, hardware design is mainly bottlenecked by high design complexity and long development time. This thesis explores the use of domain specific languages for high-level synthesis (HLS) of hardware data filters and transformations.<br/>The main goal of this thesis’ prototype is automating the...

Exploring a pure landmark-based approach for indoor localisation

Humans interact more and more with their environment through technology, recent decades have seen a huge increase in the need for and availability of Location-Based Services (LBS). Recently landmarks have gotten a renewed interest in the field of LBS , although already a quite old phenomenon. In both the outdoor and indoor environment they are...

Search-Based Test Data Generation for SQL Queries

Software testing is an important, well-researched field.<br/>With the majority of modern-day applications using relational databases to manipulate their data, it is crucial that database interactions are tested as well.<br/>This is a complex task to perform manually, and thus researchers have been attempting to tackle this problem by means of...

Zero-Downtime SQL Database Schema Evolution for Continuous Deployment

When a web service or application evolves, its database schema --- tables, constraints, and indices --- often need to evolve along with it. Depending on the database, some of these changes require a full table lock, preventing the service from accessing the tables under change. To deal with this, web services are typically taken offline...

Performance Evaluation of Distributed SQL Query Engines and Query Time Predictors

With the decrease in cost of storage and computation of public clouds, even small and medium enterprises (SMEs) are able to process large amounts of data. This causes businesses to increase the amounts of data they collect, to sizes that are difficult for traditional database management systems to handle. Distributed SQL Query Engines (DSQEs),...

Black-Box assessment of Web systems security

Many companies rely on Web applications to promote their services to the world. It is a logical step, as the Web offers great advantages such as convenience, low cost and instant reachability from anywhere in the world. Meanwhile Web applications tend to be implemented in an insecure way and the attacker does not even need to be too experienced...

Supporting the Tennis Coach: Automatically Analyzing and Evaluating Tennis Footage

Video support is becoming an indispensable tool in tennis practice sessions, especially at the professional level. Cameras are used to record a player and the current available software is used optimize the player's tennis technique, i.e. the biomechanics. Unfortunately, the tactical side of tennis is underexposed in terms of available software....