Enhanced LOB Support - Parallel Transporter

Teradata® Parallel Transporter Reference - 20.00

Deployment
VantageCloud
VantageCore
Edition
IntelliFlex
Lake
Enterprise
VMware
Product
Parallel Transporter
Release Number
20.00
Published
October 2023
ft:locale
en-US
ft:lastEdition
2023-12-06
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ogv1478610452101
lifecycle
latest
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 done automatically by the operators without any preparation by the user. Temporary LOB files will be created by the producer operator. 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.
  • Ensure that there is enough disk disk space for Teradata PT to create all 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.
  • Ensure that there is 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 be deleted from the user's system.
  • The enhanced LOB support applies only to non-z/OS platforms.