Following planned and unplanned outages, Application Continuity attempts to mask the outage by rebuilding the database session, and resubmitting the pending work following recoverable errors that make the database session unavailable. Application Continuity does not resubmit work following call failures due to non-recoverable errors. Submission of invalid data values is an example of a non-recoverable error that would not be available for replay.
When Application Continuity is configured, an end-user request is executed at-most once; replay is started if the time has not exceeded the replay timeout attribute specified for the service. When replaying, Application Continuity appears to the user as a slightly delayed execution. When replay succeeds, this feature masks applications from transient outages (such as session failure, instance or node outages, network failures, and so on) and from planned outages such as repairs, configuration changes, and patch application.
The following documents for more information about Application Continuity
To use Application Continuity, you must configure attributes for the database services that applications use, and grant permission to keep mutables, if the application allows. The application may also need to be modified to borrow and return connections.
If your application uses an integrated pool, then the request boundaries correspond to borrowing (check-out) and returning (check-in) of the connections. If your application does not return connections (and a property is not exposed to unpin these connections), then the request boundaries will need to be added to the application. Request boundaries would also need to be added if an integrated pool is not being used.
Oracle Database JDBC Developer's Guide for more information about request boundaries
Application Continuity is available with the Universal Connection Pool 12c, JDBC Type 4 Driver 12c, and Oracle WebLogic Server 12.1.2. For third party Java applications and third party Java pools, use the Oracle Database 12c JDBC Replay Driver.
This section includes the following topics: