Truncation and Performance | Functions That Use LOB Types | Teradata Vantage - Truncation and Performance - Analytics Database - Teradata Vantage

SQL External Routine Programming

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2023-07-11
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dita:id
B035-1147
lifecycle
latest
Product Category
Teradata Vantageā„¢

Consider a UDF that declares a BLOB(100000) AS LOCATOR parameter. If you call the UDF and pass in a BLOB(200000) column, truncation might occur, so Vantage must create a temporary BLOB and perform a data copy. Because Vantage stores the temporary BLOB on disk, the performance cost of the conversion is significant.

A solution is to omit the size of the BLOB argument in the function declaration, and use the default size, which is 2,097,088,000 bytes, the maximum size of a LOB.