During pushdown optimization, the Integration Service pushes the transformation logic to one database, which is called the active database. A database that does not process transformation logic is called an idle database. For example, a mapping contains two sources that are joined by a Joiner transformation. If the session is configured for source-side pushdown optimization, the Integration Service pushes the Joiner transformation logic to the source in the detail pipeline, which is the active database. The source in the master pipeline is the idle database because it does not process transformation logic.

The Integration Service uses the following criteria to determine which database is active or idle:

To push transformation logic to an active database, the database user account of the active database must be able to read from the idle databases.