WOS, ROS, and the Tuple Mover
Vertica supports INSERT, UPDATE, DELETE, and bulk load operations (COPY), intermixed with queries in a typical data warehouse workload. The storage model consists of three elements,which operate the same on each Vertica node:
Write Optimized Store (WOS) is a memory-resident data structure for storing INSERT, UPDATE, DELETE, and COPY (without /*+DIRECT*/ hints) actions. To support very fast data load speeds, the WOS stores records without data compression or indexing. The WOS organizes data by epoch and holds both committed and uncommitted transaction data.
- Read Optimized Store (ROS) is a highly optimized, read-oriented, disk storage structure. The ROS makes heavy use of compression and indexing. You can use the COPY...DIRECT and INSERT (with /*+DIRECT*/ hints) statements to load data directly into the ROS.
The Tuple Mover (TM) is the Vertica database optimizer component that moves data from memory (WOS) to disk (ROS). The Tuple Mover runs in the background, performing some tasks automatically at time intervals determined by its configuration parameters.
For further information about the WOS, ROS, and Tuple Mover, see Hybrid Storage Model in Vertica Concepts.