We study the problem of computing conjunctive queries over large databases on parallel
architectures without shared storage. Using the structure of such a query q and the skew in …

We study the problem of finding and monitoring fixed-size subgraphs in a continually
changing large-scale graph. We present the first approach that (i) performs worst-case …

In the last decade or so we have witnessed a growing interest in processing large data sets
on large distributed clusters. The idea was pioneered by the MapReduce framework, and …

This paper studies communication-oblivious algorithms under the massively parallel
computation (MPC) model. The communication patterns of these algorithms follow a …

Online monitoring is the task of identifying complex temporal patterns while incrementally
processing streams of data-carrying events. Existing state-of-the-art monitors for first-order …

Join queries involving many relations pose a severe challenge to today's query optimisation
techniques. To some extent, this is due to the fact that these techniques do not pay sufficient …

We study equi-join computation in the massively parallel computation (MPC) model.
Currently, a main open question under this topic is whether it is possible to design an …

Database systems are often confronted with queries that join many tables but ultimately only
output comparatively small aggregate information. Despite all advances in query …

We give two new approximation algorithms to compute the fractional hypertree width of an
input hypergraph. The first algorithm takes as input n-vertex m-edge hypergraph H of …

We study the design and analysis of parallel join algorithms in a topology-aware
computational model. In this model, the network is modeled as a directed graph, where each …