Enabling ODP.NET Clients to Receive FAN High Availability Events

ODP.NET connection pools can subscribe to FAN HA notifications that indicate when nodes, services, and service members are down. After a DOWN event, Oracle Database cleans up sessions in the connection pool that go to the instance and ODP.NET proactively removes connections that are no longer valid. ODP.NET establishes additional connections to existing Oracle RAC instances if the removal of invalid connections reduces the total number of connections to below the value for the Min Pool Size parameter.

When connecting to Oracle Database 12c and later, ODP.NET uses Oracle Notification Service, rather than Advanced Queuing.

Enable Fast Connection Failover for ODP.NET connection pools by subscribing to FAN high availability events. To enable Fast Connection Failover, include "HA Events=true" and "pooling=true" (the default value) in the connection string, as shown in the following example where user_name is the name of the database user and password is the password for that user:

con.ConnectionString =
   "User Id=user_name;Password=password;Data Source=odpnet;" +
   "Min Pool Size=10;Connection Lifetime=120;Connection Timeout=60;" +
   "HA Events=true;Incr Pool Size=5;Decr Pool Size=2";