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 Clearing the Request Cache. The EXPLAIN text indicates the peeked literal values.
This feature is only supported on the Block File System on the primary cluster. It is not available for the Object File System.
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.
Parameterized requests specified without a USING request modifier, but using either CLIv2 data parcel number 3 (Data) or CLIv2 parcel number 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.