Creating Custom Designs
Vertica strongly recommends that you use the physical schema design produced by Database Designer, which provides K-safety, excellent query performance, and efficient use of storage space. If any queries run less as efficiently than you expect, consider using the Database Designer incremental design process to optimize the database design for the query.
If the projections created by Database Designer still do not meet your needs, you can write custom projections, from scratch or based on projection designs created by Database Designer.
If you are unfamiliar with writing custom projections, start by modifying an existing design generated by Database Designer.