17.10 - Usage Notes - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1147-171K
Language
English (United States)

This function is used with table operators and differs from FNC_LobOpen in the data type of the first parameter.

Before you call FNC_LobRead to access the value of a large object, you must call FNC_LobOpen_CL to establish a read context.

For best performance of a table operator that is not designed to read an entire object, use the start and maxlength arguments to specify a subset of the object. If the object is on a remote AMP, it saves the cost of moving unneeded data.

Calling FNC_LobOpen_CL increases the number of outstanding read contexts by one. The maximum number of outstanding read contexts is 4.

The locator argument is validated to the extent possible. If the argument is not valid, the request that invoked the table operator fails and returns an error.