16.20 - Performance Issues for Triggers - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Detailed Topics

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
March 2019
Content Type
Programming Reference
Publication ID
B035-1184-162K
Language
English (United States)

Triggers are active database objects. The actions of creating triggers on tables and then executing them involve several system resource issues.

Application designers must evaluate the relative advantages of triggers and the possible performance impact while defining them. For example, a row trigger can complete a much larger amount of work than is done in the triggering statement, which is an SQL DML statement.

There is no limit on the number of rows that can be changed by row triggers or statement triggers. For example:

THIS type of triggered action … RESULTS in …
INSERT adding one row to a table.
INSERT... SELECT adding many rows to a table.
UPDATE updating one or multiple rows.

In many instances, the actions carried out by triggers are sufficiently useful that their use is justified even after the resulting impact on system performance is taken into consideration.