16.20 - About SCANDISK and CheckTable - Teradata Vantage NewSQL Engine

Teradata Vantageā„¢ NewSQL Engine Node Software Migration Guide

prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
created_date
March 2019
category
Administration
Configuration
Installation
featnum
B035-5942-162K
Prior to a migration or upgrade, you should validate the integrity of the database to insure against any loss of data that might result from errors in tables or a corrupted file system. Pre-existing problems on the source system can cause issues, such as the following:
  • Failure of the entire migration or upgrade operation
  • Failure to detect new problems introduced by the migration on the destination system
  • Apparent migration or upgrade problems that are not real
  • Database failures on the destination system
SCANDISK and CheckTable are system utilities that check the integrity of the database file system and tables, and report on any problems they find. For more information on these utilities and how to run them, see Teradata Vantageā„¢ - Database Utilities , B035-1102 .
These utilities may take a long time to run, depending on the priority level at which they are run, the degree of checking they do, and how much data exists on the system. To speed the utilities and minimize the effect on currently logged on users, do the following:
  • Run SCANDISK at a low priority level.
  • Run CheckDisk at a medium priority doing Level 2 checking with the following command:
    check dbc at level two with no error limit skiplocks priority=m error only;
    CheckTable commands require a semicolon at the end.
  • If there are no users logged on to the system, use the IN PARALLEL option of the CheckTable command to speed the checking.