17.05 - Constrained (Slow Path) DELETE Processing - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Manipulation Language

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
Release Date
January 2021
Content Type
Programming Reference
Publication ID
B035-1146-175K
Language
English (United States)
The processing time for a constrained delete (DELETE...WHERE) can increase when:
  • The DELETE does not meet the conditions for a fastpath delete processing. See Unconstrained Fastpath Delete Processing.
  • The FALLBACK option is specified for the table, because the rows in the secondary copy of the table must also be deleted.
  • Secondary indexes are defined for the table, because the secondary index subtable also must be updated to account for the rows deleted.

Processing time for a constrained delete can be shortened by specifying a primary index value, a USI value, or a highly selective NUSI value as the conditional expression of the WHERE clause.