Effect of Request Cache Peeking on EXPLAIN Reports - Teradata Database - Teradata Vantage NewSQL Engine

SQL Data Manipulation Language
Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Published
March 2019
Language
English (United States)
Last Update
2019-05-03
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B035-1146
lifecycle
previous
Product Category
Teradata Vantage™

If you specify USING data, or if you specify a DATE or CURRENT_DATE built-in function in a request, or both, the system can invoke Request Cache peeking. See Teradata Vantage™ SQL Request and Transaction Processing, B035-1142. In this case, the EXPLAIN text indicates the peeked literal values.

If you do not specify USING data, or if the USING variables, DATE or CURRENT_DATE values, or both are not peeked, then there is no impact on either the generated plan or the generated EXPLAIN text.

Note that parameterized requests specified without a USING request modifier, but using either CLIv2 data parcel flavor 3 (Data) or CLIv2 parcel flavor 71 (DataInfo), cannot be explained using any of the following request modifiers or statements:
  • EXPLAIN
  • DUMP EXPLAIN
  • INSERT EXPLAIN

For details about data parcel formats, see Teradata® Call-Level Interface Version 2 Reference for Mainframe-Attached Systems, B035-2417 or Teradata® Call-Level Interface Version 2 Reference for Workstation-Attached Systems, B035-2418.