13.3 Configuring Transparent Application Failover

Transparent Application Failover (TAF) instructs Oracle Net to transparently reconnect a failed connection to a different listener in the event of the failure of a database instance. This enables you to continue your work using the new connection as if the original connection never failed.

TAF involves manual configuration of a network service name that includes the FAILOVER_MODE parameter included in the CONNECT_DATA section of the connect descriptor.

Note:

For TAF and Application Continuity, Oracle recommends that you configure failover on the connected service. It overrides the client-side settings.

Learn about the TAF functionality and how to configure it in the connect string.

• About Transparent Application Failover
  Transparent Application Failover enables a client to automatically reconnect to a database instance if the current instance to which the connection is made fails. Notifications are used by the server to trigger TAF callbacks on the client-side.
• What Transparent Application Failover Restores
  TAF automatically restores some or all of these elements associated with active database connections. Other elements may need to be embedded in the application code to enable TAF and recover a connection.
• About the FAILOVER_MODE Parameters
  The FAILOVER_MODE parameter supports these additional parameters. You can specify these in the CONNECT_DATA section of a connect descriptor.
• Implementing Transparent Application Failover
  Depending on the FAILOVER_MODE parameters, you can implement TAF in several ways. Oracle recommends these methods.
• Verifying Transparent Application Failover
  You can query the FAILOVER_TYPE, FAILOVER_METHOD, and FAILED_OVER columns in the V$SESSION view to verify that TAF is correctly configured.