This document discusses in-memory databases and real-time analytics. It describes hybrid transactional/analytic processing (HTAP) which allows real-time querying of transactional data without needing to copy it to a data warehouse first. In-memory databases are presented as a solution for enabling real-time analytics by storing data in main memory for faster access without disk I/O. MemSQL is highlighted as an open-source in-memory database that supports mixed online transaction processing and online analytical processing workloads through horizontal scaling on commodity hardware.