15.00 - Unique Primary Index Considerations - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Unique Primary Index Considerations

The following factors describe the general performance considerations associated with UPIs.

  • UPIs guarantee an even distribution of table rows across the AMPs when there are many more unique values than AMPs on the system.
  • UPIs always guarantee the best retrieval and update performance for single table row access.
  • UPI values are never associated more than one base table row.
  • UPIs retrievals and updates never require a spool file.
  • Uniqueness is enforced by the system using the UPI (thereby avoiding the need for duplicate row checks for multiset tables).