PowerExchange CDC processing of LOB data depends on how the LOB data is stored. Db2 stores LOB data in the following ways:

When BLOB, CLOB, or DBCLOB data is stored fully inline, the row size in the base table space is limited by the maximum Db2 page size of 32 KB. The Db2 ECCR can capture LOB data up to the inline length, provided that this length is no greater than the 32-KB page size limit minus the size of the Db2 control fields and the size of the columns. PowerExchange delivers the inline LOB data to PowerCenter workflows that use a DB2zOS CDC application connection, as usual. A CDC workflow can write the LOB data to one or more targets.

When CLOB (including DBCLOB) data is stored fully or partially in an auxiliary table space, you can use the generated DTL__ST column in the extraction map to determine if the CLOB data in the PowerExchange Logger log files is complete or incomplete. If the CLOB data is incomplete, in the PowerCenter workflow, you can use an Expression transformation to call an unconnected Lookup transformation. The unconnected Lookup transformation can retrieve all of the current CLOB data from the Db2 source table and pass it back to the Expression. The workflow can then deliver all of the current CLOB data to the target. Informatica recommends that you use a single target because the use of multiple targets can cause updates to be applied in the wrong sequence. When a Lookup transformation is used to retrieve CLOB data, the before images of rows that contain the CLOB data are not available for an UPDATE or DELETE operation. However, the after images of rows that contain the CLOB data are available for an UPDATE or INSERT operation. For more information about using an Expression transformation and Lookup transformation, see Using Expression and Lookup Transformations to Retrieve CLOB Data That is Not Fully Stored Inline and the

PowerCenter Transformation Guide

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When BLOB data is stored fully or partially in an auxiliary table space, PowerCenter cannot retrieve all of the BLOB data because of limitations related to using binary ports in Lookup transformations. In this case, contact Global Customer Support to determine if a custom solution is available.