This document summarizes Viacom's approach to building a just-in-time data warehouse for product analytics. It discusses how Viacom uses Spark and Databricks on Amazon S3 to enable flexible exploratory analysis and A/B testing without needing to pre-define schemas or move data into a data warehouse. This just-in-time approach allows Viacom's product analysts to quickly get insights, test hypotheses, and monitor key metrics through dashboards for their mobile apps across 23 brands in over 170 countries. The summary highlights how Viacom uses this flexible approach to support their goals of growing global audiences through disciplined product development and data-driven decision making.