Directed queries were introduced in Vertica 7.2. Directed queries were originally designed to achieve two goals:
Since their introduction, users have found new and compelling ways to use directed queries—notably, using them to substitute one query for another. The following discussion focuses on one way you might leverage this capability.
- Preserve current query plans before a scheduled upgrade.
- Enable you to create query plans that improve optimizer performance.
Read more here: https://my.vertica.com/blog/new-uses-directed-queries/