Configuring Classic Capture in Archived Log Only Mode
You can configure Extract to read exclusively from the archived logs. This is known as Archived Log Only (ALO) mode.
In this mode, Extract reads exclusively from archived logs that are stored in a specified location. ALO mode enables Extract to use production logs that are shipped to a secondary database (such as a standby) as the data source. The online logs are not used at all. Oracle GoldenGate connects to the secondary database to get metadata and other required data as needed. As an alternative, ALO mode is supported on the production system.
Note:
ALO mode is not compatible with Extract operating in integrated capture mode.