Dremel: Interactive Analysis of Web-Scale Datasets

Sergey Melnik
Andrey Gubarev
Jing Jing Long
Geoffrey Romer
Shiva Shivakumar
Matt Tolton
Theo Vassilakis
Proc. of the 36th Int'l Conf on Very Large Data Bases(2010), pp. 330-339


Dremel is a scalable, interactive ad-hoc query system for analysis of read-only nested data. By combining multi-level execution trees and columnar data layout, it is capable of running aggregation queries over trillion-row tables in seconds. The system scales to thousands of CPUs and petabytes of data, and has thousands of users at Google. In this paper, we describe the architecture and implementation of Dremel, and explain how it complements MapReduce-based computing. We present a novel columnar storage representation for nested records and discuss experiments on few-thousand node instances of the system.