EXPLAIN Request Modifier - 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
dita:mapPath
fbo1512081269404.ditamap
dita:ditavalPath
TD_DBS_16_20_Update1.ditaval
dita:id
B035-1146
lifecycle
previous
Product Category
Teradata Vantage™

Purpose

Reports a summary of the query plan generated by the SQL query optimizer to process any valid SQL request, that is, the steps the system would use to resolve a request. The Optimizer processes an explained request in the same way that the request would be processed without the EXPLAIN modifier, except that the SQL within the request is not actually executed. However, for a dynamic plan, the request is partially executed.

Optionally, you can display the output as XML text instead of plain English text.

For additional information about how to interpret the reports generated by an EXPLAIN request modifier or the related Visual Explain utility, see:
  • INSERT EXPLAIN
  • Teradata Vantage™ SQL Request and Transaction Processing, B035-1142
  • Teradata® Visual Explain User Guide, B035-2504

Required Privileges

To EXPLAIN a request, you must have the permissions that are required to execute that request.

Syntax



Syntax Elements

STATIC
An EXPLAIN for the static plan is generated. This is the default. If applicable, the static plan indicates the request is eligible for incremental planning and execution (IPE).
IN XML
Return the output as XML text rather than as plain English text. For more information, see Teradata Vantage™ SQL Data Definition Language Detailed Topics , B035-1184 .
NO DDLTEXT
Do not capture the DDL text in the XML EXPLAIN text.
SQL_request
SQL request for which to return Optimizer processing information.

ANSI Compliance

EXPLAIN is a Teradata extension to the ANSI SQL:2011 standard.

Other SQL dialects support similar non-ANSI standard statements with names such as EXPLAIN PLAN.