15.00 - SysSampleOption - Teradata Database

Teradata Database Utilities

Product
Teradata Database
Release Number
15.00
Content Type
Configuration
Publication ID
B035-1102-015K
Language
English (United States)
Last Update
2018-09-25

SysSampleOption

Purpose  

Specifies whether Teradata Database should determine the appropriate amount of table data to sample for statistics collection. If not, the sample size will be 100%.

This setting is used only when a COLLECT STATISTICS SQL statement does not specify the USING SAMPLE option.

Field Group

Optimizer Statistics

Valid Settings

 

Setting

Description

0

Use factory default, currently equivalent to setting 1.

1

Enables system-determined sample percentage up to 100%.

2

Sample percentage is 100% (full statistics).

Default

0

Changes Take Effect

After the DBS Control Record has been written.

Usage Notes  

Statistics are used by the optimizer to improve query performance.

When cost profiles are in effect, this setting can be overridden by a cost profile constant value.

Related Topics

 

For more information on…

See…

Optimizer statistics fields

  • “DefaultTimeThreshold” on page 298
  • “DefaultUserChangeThreshold” on page 299
  • “SysChangeThresholdOption” on page 446
  • Cost profiles

  • DIAGNOSTIC SET PROFILE in SQL Data Manipulation Language
  • Target Level Emulation chapter in SQL Request and Transaction Processing