38 research outputs found
GRATIN: Accelerating Graph Traversals in Main-Memory Column Stores
Native graph query and processing capabilities have become indispensable for modern business applications in enterprise-critical operations on data that is stored in relational database management systems. Traversal operations are a basic ingredient of graph algorithms and graph queries. As a consequence, they are fundamental for querying graph data in a relational database management system. In this paper we present gratin, a concise secondary index structure to speedup graph traversals in main-memory column stores. Conventional approaches for graph traversals rely on repeated full column scans, making it an inefficient approach for deep traversals on very large graphs. To tackle this challenge, we devise a novel and adaptive block-based index to handle graphs efficiently. Most importantly, gratin is updateable in constant time and allows supporting evolving graphs with frequent updates to the graph topology. We conducted an extensive evaluation on real-world data sets from different domains for a large variety of traversal queries. Our experiments show improvements of up to an order of magnitude compared to a scan-based traversal algorithm
An End-to-end Neural Natural Language Interface for Databases
The ability to extract insights from new data sets is critical for decision
making. Visual interactive tools play an important role in data exploration
since they provide non-technical users with an effective way to visually
compose queries and comprehend the results. Natural language has recently
gained traction as an alternative query interface to databases with the
potential to enable non-expert users to formulate complex questions and
information needs efficiently and effectively. However, understanding natural
language questions and translating them accurately to SQL is a challenging
task, and thus Natural Language Interfaces for Databases (NLIDBs) have not yet
made their way into practical tools and commercial products.
In this paper, we present DBPal, a novel data exploration tool with a natural
language interface. DBPal leverages recent advances in deep models to make
query understanding more robust in the following ways: First, DBPal uses a deep
model to translate natural language statements to SQL, making the translation
process more robust to paraphrasing and other linguistic variations. Second, to
support the users in phrasing questions without knowing the database schema and
the query features, DBPal provides a learned auto-completion model that
suggests partial query extensions to users during query formulation and thus
helps to write complex queries
Weiterentwicklung analytischer Datenbanksysteme
This thesis contributes to the state of the art in analytical database systems. First, we identify and explore extensions to better support analytics on event streams. Second, we propose a novel polygon index to enable efficient geospatial data processing in main memory. Third, we contribute a new deep learning approach to cardinality estimation, which is the core problem in cost-based query optimization.Diese Arbeit trĂ€gt zum aktuellen Forschungsstand von analytischen Datenbanksystemen bei. Wir identifizieren und explorieren Erweiterungen um Analysen auf Eventströmen besser zu unterstĂŒtzen. Wir stellen eine neue Indexstruktur fĂŒr Polygone vor, die eine effiziente Verarbeitung von Geodaten im Hauptspeicher ermöglicht. Zudem prĂ€sentieren wir einen neuen Ansatz fĂŒr KardinalitĂ€tsschĂ€tzungen mittels maschinellen Lernens
Complaint-driven Training Data Debugging for Query 2.0
As the need for machine learning (ML) increases rapidly across all industry
sectors, there is a significant interest among commercial database providers to
support "Query 2.0", which integrates model inference into SQL queries.
Debugging Query 2.0 is very challenging since an unexpected query result may be
caused by the bugs in training data (e.g., wrong labels, corrupted features).
In response, we propose Rain, a complaint-driven training data debugging
system. Rain allows users to specify complaints over the query's intermediate
or final output, and aims to return a minimum set of training examples so that
if they were removed, the complaints would be resolved. To the best of our
knowledge, we are the first to study this problem. A naive solution requires
retraining an exponential number of ML models. We propose two novel heuristic
approaches based on influence functions which both require linear retraining
steps. We provide an in-depth analytical and empirical analysis of the two
approaches and conduct extensive experiments to evaluate their effectiveness
using four real-world datasets. Results show that Rain achieves the highest
recall@k among all the baselines while still returns results interactively.Comment: Proceedings of the 2020 ACM SIGMOD International Conference on
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Scalable Systems for Large Scale Dynamic Connected Data Processing
As the proliferation of sensors rapidly make the Internet-of-Things (IoT) a reality, the devices and sensors in this ecosystemâsuch as smartphones, video cameras, home automation systems, and autonomous vehiclesâconstantly map out the real-world producing unprecedented amounts of dynamic, connected data that captures complex and diverse relations. Unfortunately, existing big data processing and machine learning frameworks are ill-suited for analyzing such dynamic connected data and face several challenges when employed for this purpose.This dissertation focuses on the design and implementation of scalable systems for dynamic connected data processing. We discuss simple abstractions that make it easy to operate on such data, efficient data structures for state management, and computation models that reduce redundant work. We also describe how bridging theory and practice with algorithms and techniques that leverage approximation and streaming theory can significantly speed up connected data computations. The systems described in this dissertation achieve more than an order of magnitude improvement over the state-of-the-art
Materialisierte views in verteilten key-value stores
Distributed key-value stores have become the solution of choice for warehousing large volumes of data. However, their architecture is not suitable for real-time analytics. To achieve the required velocity, materialized views can be used to provide summarized data for fast access. The main challenge then, is the incremental, consistent maintenance of views at large scale. Thus, we introduce our View Maintenance System (VMS) to maintain SQL queries in a data-intensive real-time scenario.Verteilte key-value stores sind ein Typ moderner Datenbanken um groĂe Mengen an Daten zu verarbeiten. Trotzdem erlaubt ihre Architektur keine analytischen Abfragen in Echtzeit. Materialisierte Views können diesen Nachteil ausgleichen, indem sie schnellen Zuriff auf Ergebnisse ermöglichen. Die Herausforderung ist dann, das inkrementelle und konsistente Aktualisieren der Views. Daher prĂ€sentieren wir unser View Maintenance System (VMS), das datenintensive SQL Abfragen in Echtzeit berechnet