15.00 - Host Utility Locks - Teradata Database

Teradata Database Utilities

Teradata Database
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Host Utility Locks

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 locks are associated with the currently logged-on user who entered the command, rather than with a batch job or transaction.
  • Only the AMPs that are participating in the Archive/Recovery operation are locked.
  • Archive/Recovery locks 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. 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.
  • Archive/Recovery locks remain active until you release them.
  • Note: If Archive/Recovery locks are not specifically released, they are automatically reinstated following a Teradata Database or client system restart.