Enhanced LOB Support - Parallel Transporter

Teradata® Parallel Transporter Reference

Parallel Transporter
Release Number
February 2022
English (United States)
Last Update
Product Category
Teradata Tools and Utilities

Teradata PT now supports schemas containing rows with inline LOBs (CLOB, BLOB, JSON, and XML data types) that exceed the 1MB record limit. Non-LOB data and smaller inline LOBs (total not to exceed 1MB) will be transferred as is. But larger inline LOB columns will be transferred in deferred mode. This is all done automatically by the operators without any preparation by the user. Temporary LOB files will be created by the producer operator. And once processed by the consumer operator, the temporary LOB files will be removed.

Therefore, large LOB columns do not have be transferred using the "AS DEFERRED BY NAME" clause and pre-defined LOB files do not need to exist.

Important Details

  • Teradata recommends defining a CLOB, BLOB, or JSON column using a specific size. If no size is specified, then the maximum size is used, making the transfer less efficient.
  • Define the sizes for CLOB, BLOB, and JSON columns as accurately as possible. For example, if the maximum size for one particular object is 12,000 bytes, but a definition of CLOB(50000) is used, that leads to more inefficiency.
  • It is the user's responsibility to have enough disk disk space for Teradata PT to create all of the temporary LOB files that it needs to create. These temporary LOB files will be removed, but disk usage may be high during the transfer.
  • It is the user's responsibility to have enough memory available in the system whenever transferring large LOB columns. Both the producer and the consumer have to store the LOB data in memory at some point.
  • If an active job is killed, temporary LOB files may not get deleted from the user's system.