15.00 - DisableWALforDBs - 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

DisableWALforDBs

Purpose  

Determines whether changed data blocks are written directly to disk or to the Write-Ahead Logging (WAL) log.

Note: This setting is effective only when WAL is enabled (DisableWAL is set to FALSE).

Field Group

File System

Valid Settings

 

Setting

Description

TRUE

Changed data blocks are written to disk.

FALSE

Changed data blocks are written to the WAL log and cached in memory, or may be written to disk, depending on the specific operation.

Default

FALSE

Changes Take Effect

After the DBS Control Record has been written.

Usage Notes  

WAL is a log-based file system recovery scheme in which modifications to permanent data are written to a log file, the WAL log. The log file contains change records (Redo records) which represent the updates. At key moments, such as transaction commit, the WAL log is forced to disk. In the case of a reset or crash, Redo records can be used to transform the old copy of a permanent data block on disk into the version that existed at the time of the reset.

Related Topics

See “DisableWALforDBs” on page 317.