In this talk, Fangjin Yang of MetaMarkets will talk on their motivations for building druid, its architecture, how it works, and its real-time capabilities. Druid is open source infrastructure for Real²time Exploratory Analytics on Large Datasets. The system uses an always-on, distributed, shared-nothing, architecture designed for real-time querying and data ingestion. It leverages column-orientation and advanced indexing structures to allow for cost effective, arbitrary exploration of multi-billion-row tables with sub-second latencies. This talk was recorded at the SF Data Engineering meetup at Square.