Effective in version 10.0, the impact summary lists PowerCenter Session task instances. The impact summary lists a Session task instance when you view metadata details for an object that impacts or is impacted by a PowerCenter mapping. When you export the metadata object and include the impact summary, the export file also lists the associated Session task instance in the Impact Summary section.
The impact summary lists the Session task instance because it can affect the data flow. A Session task instance can override source or target connection information. It can also contain an SQL query that overrides the default query used to extract data from the source.
For more information about the impact summary, see the "Viewing Metadata" chapter in the