17.10 - Host Utility Locks - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - Database Utilities

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Configuration
Publication ID
B035-1102-171K
Language
English (United States)

You can release HUT locks either by submitting a separate RELEASE LOCK SQL command, or by using the RELEASE LOCK option of the appropriate command. For example, ARCHIVE, ROLLBACK, RESTORE, BUILD, and ROLLFORWARD.

HUT locks placed by the Archive/Recovery utility differ from locks placed by other operations or transactions. HUT locks have the following characteristics:

  • Archive/Recovery (ARC utility) HUT locks are associated with the currently logged-on user who entered the command, rather than with a batch job or transaction. Data Stream Architecture (DSA) HUT locks are placed at the job level.
  • An ARC operation can place HUT locks on all AMPs, a single AMP, or a group of AMPs. DSA operations always place all-AMP HUT locks.
  • HUT locks for ARC that are placed at one level of an object never conflict with a utility lock at another level that was placed on the same object for the same user. HUT locks for DSA are always placed at the job level. The locking modes and levels are applied as follows:
    • A Read lock is placed on an object being dumped.
    • Locks are placed at the cluster level during a CLUSTER dump.
    • If a table being dumped is defined for an after-image permanent journal (and the appropriate option was selected on the DUMP command), a group Read lock is placed on the table rows.
    • A Write lock is placed on all tables involved in ROLLFORWARD and ROLLBACKWARD recovery operations.
    • A Write lock is placed on a journal table that is being deleted.
    • A Write lock is placed on a permanent journal table that is being restored.
    • An Exclusive lock is placed on any object being restored that is not a journal table.
  • DSA does not preserve permanent journal settings for a table. After the table is restored using DSA, there will be no permanent journaling for the table.
  • Archive/Recovery locks remain active until you release them.
If Archive/Recovery locks are not specifically released, they are automatically reinstated following a database or client system restart.