When a bulk load client submits data for loading, Unity controls the data load operation on each target Teradata system. Bulk load operations are run independently across multiple Teradata systems, and automatic recovery and restarts occur if data loading is interrupted. Systems that fail to load data are automatically reloaded when the system is restored. For consistency, Unity compares the results of the data load operation across Teradata systems.
- Data cannot be loaded to one or more of the target systems due to target, error, or restart tables in the interrupted state or an unavailable target system.
- A data checkpoint did not occur on all systems, and there is insufficient memory to store the data in memory.
- A data checkpoint is successful on one system, but not on the others.
Unity deletes landed data stored on the disk array after the data successfully loads to the Teradata systems, or the begin loading record of the bulk load job is overwritten in the recovery log. Management of the disk space by Unity reduces the total amount of disk space required for the load files.