Efficiently Charting RDF

11/27/2018
by   Oren Kalinsky, et al.
0

We propose a visual query language for interactively exploring large-scale knowledge graphs. Starting from an overview, the user explores bar charts through three interactions: class expansion, property expansion, and subject/object expansion. A major challenge faced is performance: a state-of-the-art SPARQL engine may require tens of minutes to compute the multiway join, grouping and counting required to render a bar chart. A promising alternative is to apply approximation through online aggregation, trading precision for performance. However, state-of-the-art online aggregation algorithms such as Wander Join have two limitations for our exploration scenario: (1) a high number of rejected paths slows the convergence of the count estimations, and (2) no unbiased estimator exists for counts under the distinct operator. We thus devise a specialized algorithm for online aggregation that augments Wander Join with exact partial computations to reduce the number of rejected paths encountered, as well as a novel estimator that we prove to be unbiased in the case of the distinct operator. In an experimental study with random interactions exploring two large-scale knowledge graphs, our algorithm shows a clear reduction in error with respect to computation time versus Wander Join.

READ FULL TEXT

page 4

page 6

research
06/21/2021

A Logical Model for joining Property Graphs

The present paper upgrades the logical model required to exploit materia...
research
11/16/2021

The Case for Learned In-Memory Joins

In-memory join is an essential operator in any database engine. It has b...
research
08/31/2023

SieveJoin: Boosting Multi-Way Joins with Reusable Bloom Filters

Improving data systems' performance for join operations has long been an...
research
05/27/2022

Efficient Semantic Summary Graphs for Querying Large Knowledge Graphs

Knowledge Graphs (KGs) integrate heterogeneous data, but one challenge i...
research
08/20/2020

DPMC: Weighted Model Counting by Dynamic Programming on Project-Join Trees

We propose a unifying dynamic-programming framework to compute exact lit...
research
07/01/2023

Aggregation Consistency Errors in Semantic Layers and How to Avoid Them

Analysts often struggle with analyzing data from multiple tables in a da...
research
09/30/2022

Offset-value coding in database query processing

Recent work shows how offset-value coding speeds up database query execu...

Please sign up or login with your details

Forgot password? Click here to reset