About MultiLoad - Teradata Database

MultiLoad allows you to upload data from the client to your Teradata Database. It operates on multiple tables simultaneously and can also insert, update, and delete data.

The maximum number of MultiLoad jobs you can run is 30. The default is 5. You can also change the maximum number of jobs allowed by defining throttle rules through the Teradata Viewpoint Workload Designer portlet. (See “Maximum Number of Concurrent FastLoad, MultiLoad, and FastExport Jobs” on page 141 for more information.)

To improve performance:

Minimize concatenation and redefinition of input data.

Restrict the number of NUSIs.

Make the PI of each data table unique or nearly unique.

Minimize the use of error tables.

Do not checkpoint too often.

Avoid using too many sessions.

MultiLoad does not support the following:

Aggregate operators

Exponential operators

Arithmetic functions

Concatenation of data files

Hexadecimal forms

NoPI tables

Foreign keys

Loading LOBs

Column-partitioned tables

For more information, see Teradata MultiLoad Reference.

You can perform the following steps as an alternative to using MultiLoad:

1 Create a staging table that is otherwise identical with the target table, but has no constraints, triggers, or indexes defined on it, such as a NoPI.

2 Import into the staging table from the external source (for example, using Fastload or Teradata Parallel Data Pump Array INSERT operations).

3 (Optional) create an error table for the target table if error logging is desired.

4 Execute a MERGE into the target table using the staging table as source.

5 Drop the staging table and error table.

For information on NoPI tables or Teradata Parallel Data Pump Array INSERT operations, see Database Design.