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

Product
Teradata Data Mover
Release Number
17.11
Release Date
October 2021
Content Type
User Guide
Publication ID
B035-4101-091K
Language
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.