Google Bigquery is a data analysis tool, which can crunch terabytes of data on demand in seconds using SQL queries without using expensive in-memory technology.

It has been used extensively inside of Google for analyzing large datasets and log files for years and is also available externally.

The scientific paper about Dremel ("Dremel: Interactive Analysis of Web-Scale Datasets") explains the algorithms behind the tool.

This talk goes through the algorithms in a simplified and accessible way by visualizing how Dremel executes a query on a small dataset.