When you submit a query to Vertica, the Vertica query optimizer automatically assembles a query plan, which consists of a set of operations to compute the requested result. Depending on the properties of the projections defined in your database, the query optimizer can choose faster and more efficient operations. Thus, it’s important to recognize what you can do to optimize your projections to improve query performance.
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https://my.vertica.com/kb/Redesigning-P ... zation.htm