  Column-oriented database systems have been a real game changer for the
industry in recent years. Highly tuned and performant systems have evolved that
provide users with the possibility of answering ad hoc queries over large
datasets in an interactive manner. In this paper we present the column-oriented
datastore developed as one of the central components of PowerDrill. It combines
the advantages of columnar data layout with other known techniques (such as
using composite range partitions) and extensive algorithmic engineering on key
data structures. The main goal of the latter being to reduce the main memory
footprint and to increase the efficiency in processing typical user queries. In
this combination we achieve large speed-ups. These enable a highly interactive
Web UI where it is common that a single mouse click leads to processing a
trillion values in the underlying dataset.
