16.10 - Usage Notes - Teradata Database

Teradata Database Support Utilities

Teradata Database
June 2017

Reconfiguration Estimator time estimates are affected by how busy the system is while the estimates are being generated. The accuracy of estimates is improved when other system work is minimized, and best when Reconfiguration Estimator runs on an idle system.

Reconfig Estimator checks to see if a new configuration has been defined. If so, the utility will use the new configuration to determine the changes being made to the system. If a new configuration has not been defined, the utility prompts for the configuration changes to be made.
Teradata recommends that you make any configuration changes before you run Reconfig Estimator, particularly if you are modifying AMPs.This allows the utility to analyze the configuration maps to determine which tables to process.

If you are adding AMPs to the configuration, Reconfig Estimator asks you which tables will be redistributed: Data Dictionary tables, specific user tables, all tables, or no tables.

Reconfig Estimator performs a sample run of the Reconfiguration utility in order to determine estimation constants that are appropriate for the system. Because this process involves inserting and deleting sample data, the program requires the user name and password of an account that has rights to create and insert table rows. Create a user account exclusively for the use of Reconfiguration Estimator, and assign it a non-critical password. (The username and password you enter are visible in Reconfiguration Estimator user interface.) Grant the account all privileges specified above. The account should have at least .5 to 1 GB of perm space per system AMP.

Best estimates are obtained when Pseudo Reconfig (as noted in the utility output) runs for five to ten minutes on an idle system. The minimal time required to obtain reasonable estimates is proportional to how busy the system is while the estimates are being calculated. For example, if the system is only 10% idle, best estimates are obtained if the utility runs for 50 to 100 minutes. If Reconfiguration Estimator runs for less than an optimal time, run the utility again, after increasing the amount of perm space assigned to the account used by Reconfig Estimator.

If Reconfiguration Estimator encounters any problems, the estimation process aborts and returns an error message.

Do not run multiple instances of Reconfiguration Estimator simultaneously.

For more information on the reconfiguration process, see Reconfiguration Utility (reconfig).