Use MERGE to Copy Data | Performance | Teradata Data Mover - 17.11 - About Using the Merge Table Feature - Teradata Data Mover

Teradata® Data Mover User Guide

Teradata Data Mover
Release Number
Release Date
October 2021
Content Type
User Guide
Publication ID
English (United States)

In some circumstances, Data Mover uses MERGE instead of INSERT-SELECT when copying data from a staging database to a target database. The result is better performance.

The following conditions must be met for Data Mover when using MERGE:

  • A partial table copy must be specified.
  • The table cannot be a multiset table.
  • The table must contain one or more primary indexes.
  • All indexes must be specified as key columns.
  • For PPI tables, all partitioned columns must be specified as key columns.
  • The primary index on the target table does not contain an identity column.

If these conditions are not met, Data Mover uses DELETE and INSERT-SELECT to transfer data.

For PPI tables, indexes and partitioned columns must be specified as key columns. Specifying only the indexes as key columns results in a failed job execution.