16.20 - Aggregate Cache and Aggregate UDFs - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
16.20
Release Date
April 2020
Content Type
Programming Reference
Publication ID
B035-1147-162K
Language
English (United States)

To enhance performance, Teradata Database caches intermediate aggregate storage areas. The size of the aggregate cache is fixed at 1 MB.

If the number of intermediate storage areas exceeds the capacity of the aggregate cache, Teradata Database pages the least recently used intermediate storage areas to a spool file on disk, which causes a larger number of aggregation phases to occur and impacts performance.

For details on improving aggregate cache usage for an aggregate UDF, including how to determine the maximum number of intermediate storage areas, see “CREATE FUNCTION” in Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.