Because SQL statements are sent to Teradata Database by group in the order in which they are specified in the Teradata PT APPLY statement, the DDL operator can take a checkpoint after each group is executed. A group can contain one or more SQL statements. A checkpoint, with respect to the DDL operator, marks the last group of DDL/DML SQL statements to execute successfully.
The DDL operator restarts at the beginning of the group of SQL statements whose execution is interrupted by an abnormal termination. If the interrupted group has only one SQL statement, the DDL operator restarts at that statement.
If the last request was successful prior to a restart, the operator can resume at the next request in line. If the last request failed prior to a restart, then the operator resumes at the failed request.