Local Journaling - TARA/ABU

Local Journaling

Teradata ARC allows specifying whether single after-image journal rows for nonfallback data tables are written on the same AMP as the changed data rows (called local single after-image journaling) or written to another AMP in the cluster (called remote single after-image journal).

Use the local single after-image journal only with nonfallback tables. It is specified with the JOURNAL option in these SQL statements:

CREATE DATABASE

CREATE USER

MODIFY DATABASE

MODIFY USER

CREATE TABLE

ALTER TABLE

The system dictionary table/view columns describing journaling types are modified to be able to describe LOCAL single after-image journaling.

Teradata ARC rules for local single after-image journal and single before-image journal are the same except that a single local after-image journal is used with ROLLFORWARD only and single before-image journal is used with ROLLBACK only.

Local single after-image journaling reduces AMP path length. Without file system fault isolation support, the recoverability of user data tables against certain type of software errors with local single after-image journaling is less efficient than recovering with remote single after-image journaling.