The document describes Vertica's hybrid data store architecture, which includes a Write Optimized Store (WOS) and Read Optimized Store (ROS). The WOS stores data in-memory for low latency loading, while the ROS stores data on disk in a column-oriented and compressed format for efficient querying. A tuple mover asynchronously transfers data from the WOS to the ROS in the background. This hybrid approach allows for both fast load times and fast query performance.