Configuring Classic Capture in Oracle Active Data Guard Only Mode
You can configure Classic Extract to access both redo data and metadata in real-time to successfully replicate source database activities using Oracle Active Data Guard. This is known as Active Data Guard (ADG) mode.
ADG mode enables Extract to use production logs that are shipped to a standby database as the data source. The online logs are not used at all. Oracle GoldenGate connects to the standby database to get metadata and other required data as needed.
This mode is useful in load sensitive environments where ADG is already in place or can be implemented. It can also be used as cost effective method to implement high availability using the ADG Broker role planned (switchover) and failover (unplanned) changes. In an ADG configuration, switchover and failover are considered roles. When either of the operations occur, it is considered a role change. For more information, see Oracle Data Guard Concepts and Administration and Oracle Data Guard Broker.
You can configure Integrated Extract to fetch table data and metadata required for the fetch from an ADG instead of the source database. This is possible because an ADG is a physical replica of the source database. Fetching from an ADG using the FETCHUSER parameter is supported by Extract in all configurations except when running as Classic Extract. Classic Extract already has the ability to connect directly to an ADG and mine its redo logs and fetch from it using standard connection information supplied using the USERID parameter. The impact to the source database is minimized because Extract gathers information from the source database at startup, including compatibility level, database type, and source database validation checks, when fetching from an ADG.
All previous fetch functionality and parameters are supported.
Note:
Integrated Extract cannot capture from a standby database because it requiresREAD and WRITE access to the database, and an ADG standby only provides READ ONLY access.