16.10 - SelectStmt - Parallel Transporter

Teradata Parallel Transporter Reference

Product
Parallel Transporter
Release Number
16.10
Published
July 2017
Content Type
Programming Reference
Publication ID
B035-2436-077K
Language
English (United States)

The SQL Selector operator supports a single Teradata SQL SELECT statement or multiple SELECT statements.

Certain restrictions apply when using a Teradata SQL SELECT statement in the SQL Selector operator:

  • Do not specify a WITH clause with a SELECT statement. Use of a WITH or WITH BY clause produces an error message.
  • Do not specify a USING modifier with a SELECT statement. Use of a USING modifier produces an error message.
The SQL Selector operator only logs on to one Teradata Database session. Multiple SELECT statements are therefore sent as one request to the Teradata Database. The Teradata Database executes these multiple statements sequentially. Thus, the SQL Selector operator cannot take advantage of the parallel processing environment that Teradata PT offers. To take advantage of parallel processing, break multiple Teradata SQL SELECT statement requests into single SELECT statements carried by multiple SQL Selector operators, and then unite these data sources together with the UNION clause.