When you submit a query to Vertica for processing, the Vertica query optimizer automatically chooses a set of operations to compute the requested result. These operations together are called a query plan. The choice of operations can significantly affect how many resources are needed to compute query results, and overall run-time performance. Optimal performance depends in great part on the projections that are available for a given query.
This section describes the different operations that the optimizer uses and how you can facilitate optimizer performance.
Database response time depends on many factors. These include type and size of the application query, database design, data size and data types stored, available computational power, and network bandwidth. Adding nodes to a database cluster does not necessarily improve the system response time for every query, especially if response times are already short, or are not hardware bound.