Vertica Analytics Platform Version 9.2.x Documentation
Working with Projections
Unlike traditional databases that store data in tables, Vertica physically stores table data in projections, which are collections of table columns.
Projections store data in a format that optimizes query execution. Similar to materialized views, they store result sets on disk rather than compute them each time they are used in a query. Vertica automatically refreshes these result sets with updated or new data.
Projections can be generally classified in two ways:
- How projection data is distributed on the cluster. A projection can be defined to divide its data into multiple segments, or maintain all projection data as a single unsegmented unit.
- How much data a projection contains, and the nature of that data. For example, each table Vertica requires a superprojection, which contains all table columns. You can also create query-specific projections, which contain only the subset of table columns to process a given query.
For more general information about Vertica projections, see Physical Schema in Vertica Concepts.
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