Source Qualifier Transformation with an SQL Override
Source Qualifier Transformation with an SQL Override
Use the following rules and guidelines when you configure pushdown optimization for a session containing a Source Qualifier transformation with an SQL override:
The SELECT statement in a custom SQL query must list the port names in the order in which they appear in the transformation. If the ports are not in the correct order, the session can fail or output unexpected results.
Configure the session for pushdown optimization with a view.
The session fails if the SELECT statement in the SQL override refers to a database sequence.
The session fails if the SQL override contains an ORDER BY clause and you push the Source Qualifier transformation logic to an IBM DB2, a Microsoft SQL Server, a Sybase ASE, or a Teradata database.
If a Source Qualifier transformation is configured to select distinct values and contains an SQL override, the Integration Service ignores the distinct configuration.
If the session contains multiple partitions, specify the SQL override for all partitions.
You must disable the creation of temporary views for pushdown optimization to Teradata when the Source Qualifier transformation contains an SQL override. The PowerCenter Integration Service creates derived tables instead of views.
Test the SQL override query on the source database before you push it to the database because PowerCenter does not validate the override SQL syntax. The session fails if the SQL syntax is not compatible with the source database.