Target tables can be either fallback or nonfallback.
The following table lists the differences between, and characteristics of, these tables.
| Fallback Tables | Nonfallback Tables |
|---|---|
| Teradata TPump task continues to execute even if AMPs are down, as long as there is not more than one AMP down, either logically or physically in a cluster. | If one or more AMPs are down prior to entering the task and if one or more target tables are nonfallback, Teradata TPump terminates. |
| If two or more AMPs in a cluster are logically or physically down, or both, the task does not run, or terminates if running. | The Teradata TPump task may be restarted as soon as all AMPs are back up. |
| During the task, if AMPs are down to the extent that data on the disk is corrupted, the affected tables must be restored. | If an AMP goes down once the task has started, the task cannot be restarted until all AMPs are back up. |
| Not applicable. | If more than one AMP in the same cluster is down, the database cannot come up. |
| Not applicable. | Certain I/O errors during the task corrupt the target table so that it must be restored. In this case, Teradata TPump terminates. |