When you load to Teradata targets, use one of the following external loaders:
Performs insert, update, delete, and upsert operations for large volume incremental loads. Use this loader when you run a session with a single partition. Multiload acquires table level locks, making it appropriate for offline loading.
Performs insert, update, delete, and upsert operations for relatively low volume updates. Use this loader when you run a session with multiple partitions. TPump acquires row-hash locks on the table, allowing other users to access the table as TPump loads to it.
Performs insert operations for high volume initial loads, or for high volume truncate and reload operations. Use this loader when you run a session with a single partition. Use this loader on empty tables with no secondary indexes.
If you use a Teradata external loader to perform update or upsert operations, use the Target Update Override option in the Mapping Designer to override the UPDATE statement in the external loader control file. For upsert, the INSERT statement in the external loader control file remains unchanged.