Defining Custom Projections
Vertica strongly recommends that you use the physical schema design produced by the 
Database Designer, which provides K-Safety, excellent ad-hoc query performance and efficient use of storage space. However, if you find that the projections produced by the Database Designer are not satisfactory, contact Vertica Technical Support and provide your:
To submit problem reports, questions, comments, and suggestions, please use the Technical Support page on the Vertica Systems, Inc. Web site:
http://www.vertica.com/support
You must be a registered user in order to access the page.
Before reporting a problem, please run the Diagnostics Utility described in the Troubleshooting Guide and attach the resulting .zip file.
K represents the maximum number of nodes in a database that can fail and recover with no loss of data. In Vertica V2.1, the value of K can be zero (0) or one (1). The value of K can be one (1) only when the Physical Schema design meets certain requirements. The designs generated by the Database Designer are K-Safe.
A physical schema consists of a set of projections used to store data on disk. The projections in the physical schema are based on the objects in the Logical Schema.
The Database Designer is a tool that analyzes a logical schema definition, sample queries, and sample data and generates a set of projections in the form of an SQL script to be executed after you create the tables but before you load any data. The script creates a minimal set of superprojections to ensure K-Safety, and optionally pre-join projections. In most cases, the projections created by the Database Designer provide excellent query performance within physical constraints. You can, however, write a custom projection script should the Database Designer not meet your needs.
A superprojection is a projection that contains every column of a table in the Logical Schema. A table can have multiple superprojections with different sort orders.
- logical schema definition
- sample data files
- sample queries
- parameters used to run the Database Designer
- projection script created by the Database Designer
- description of your reasons for wanting to write custom projections
Technical Support may be able to provide a solution that does not involve custom projections, or that involves adding custom query-specific projections to the physical schema design.
To submit problem reports, questions, comments, and suggestions, please use the Technical Support page on the Vertica Systems, Inc. Web site:
http://www.vertica.com/support
You must be a registered user in order to access the page.
Before reporting a problem, please run the Diagnostics Utility described in the Troubleshooting Guide and attach the resulting .zip file.
Should you decide to create your own physical schema design:
