When executing the DELETE statement, Teradata simply flags the transaction as having a "deferred action" and writes a record describing the required action into the transient journal. At commit time, an "End-1" is written to the TJ, indicating that the transaction is committed but not yet completed. Then the TJ is scanned to identify and execute all the deferred actions. Finally, an "End-2" is written to the TJ, indicating that all deferred actions have been completed.
In the event of a system restart, if a tranaction is found to have the End-1 but the End-2 is missing, then transaction recovery will identify and complete all the pending deferred actions.