HTAP, a term coined by Gartner, is short for hybrid transaction / analytical processing. HTAP is a Big Data-related business application phrase that refers to databases that perform simultaneous transactions and analytics in real-time.
Ideally the hybrid transaction / analytical processing system would deliver operational throughput on high-velocity data streams as the analytics workload is added and operates in parallel, without needing to duplicate data. HTAP Systems are commercially available from a number of vendors including SAP, Clustrix, and MemSQL.