Use DBMS_APP_CONT_ADMIN to enable Application Continuity or Transparent Application Continuity:

• Application Continuity (AC): Set this failover option using the procedure DBMS_APP_CONT_ADMIN.ENABLE_AC. The ENABLE_AC procedure takes three parameters: SERVICE NAME is the service name to change, FAILOVER_RESTORE, set to LEVEL1 to select Application Continuity(AC), and REPLAY_INITIATION_TIMEOUT, is the replay timeout that specifies how many seconds after a request is submitted to allow that request to replay.

  For example, as the ADMIN user, to enable Application Continuity for the TPURGENT service:

  execute DBMS_APP_CONT_ADMIN.ENABLE_AC(
          'databaseid_tpurgent.adb.oraclecloud.com', 'LEVEL1', 600);

• Transparent Application Continuity (TAC): Set this failover option using the procedure DBMS_APP_CONT_ADMIN.ENABLE_TAC. The ENABLE_TAC procedure takes three parameters: SERVICE NAME is the service name to change, FAILOVER_RESTORE, set to AUTO to select Transparent Application Continuity (TAC), and REPLAY_INITIATION_TIMEOUT is the replay timeout that specifies how many seconds after a request is submitted to allow that request to replay.

  For example, as the ADMIN user, to enable Transparent Application Continuity for the TP service with the replay timeout set to 20 minutes:

  execute DBMS_APP_CONT_ADMIN.ENABLE_TAC(
          'databaseid_tp.adb.oraclecloud.com', 'AUTO', 1200);
  

• Disabled: Disable failover using the procedure DBMS_APP_CONT_ADMIN.DISABLE_FAILOVER().

  For example, as the ADMIN user, to disable failover for the TP service:

  execute DBMS_APP_CONT_ADMIN.DISABLE_FAILOVER(
          'databaseid_tp.adb.oraclecloud.com');
  

When connecting to Autonomous Database, the Oracle database auto-configures FAN. For application deployments with Autonomous Database, Fast Application Notification (FAN) events for unplanned outages are directed to the connection manager (CMAN) and no client application configuration steps required to use FAN.

FAN is automatically handled for you by the client driver and by the Autonomous Database Connection Manager (CMAN):

• For planned maintenance events, FAN is sent in-band, directly to the drivers. This requires that applications use Oracle Pools or TAC for request boundaries, or use connection tests.
• The Oracle Database and Oracle client drivers drain on connection tests and at request boundaries.

See Client Configuration for Continuous Availability on Autonomous Database for more information.

To maintain high availability, Oracle recommends that you set certain connection string parameters when you connect to Oracle Autonomous Database.

Set the CONNECT_TIMEOUT, RETRY_DELAY, RETRY_COUNT, and TRANSPORT_CONNECT_TIMEOUT parameters in the connection string when you connect to Oracle Autonomous Database. The connect strings embedded in the Oracle-supplied tnsnames.ora file are preconfigured with appropriate values for most applications. In some cases, depending on your applications needs, you may need to change the preconfigured values for a connection string.

Use this TNS for all Oracle clients version 12.2 or higher:

alias =
(DESCRIPTION =
(CONNECT_TIMEOUT= 90)(RETRY_COUNT=50)
(RETRY_DELAY=3)(TRANSPORT_CONNECT_TIMEOUT=3)
(ADDRESS_LIST =
  (LOAD_BALANCE=on)
  (ADDRESS = (PROTOCOL = TCP)(HOST=scan-host)(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME = service-name)))

Use the following for JDBC connections using Oracle driver version 12.1 or earlier:

alias =
(DESCRIPTION =
(CONNECT_TIMEOUT= 15)(RETRY_COUNT=50)
(RETRY_DELAY=3)
(ADDRESS_LIST =  
   (LOAD_BALANCE=on)  
   (ADDRESS = (PROTOCOL = TCP)(HOST=scan-host)(PORT=1521)))
 (CONNECT_DATA=(SERVICE_NAME = service-name)))

Notes for connection strings:

• For JDBC and ODP clients, the pool connection wait time should be configured to be longer than the CONNECT_TIMEOUT in the connect string.

• Do not use Easy Connect Naming on the client because such connections do not have high-availability capabilities.

See Download Client Credentials (Wallets) for information on the tnsnames.ora file.

• Configure JDBC Thin Driver
  Shows details to use Application Continuity with Autonomous Database with a client using the JDBC Thin Driver.
• Configure Oracle Call Interface (OCI) Driver
  Shows details to use Application Continuity with Autonomous Database with a client using the Oracle Call Interface (OCI) driver.
• Configure ODP.NET Unmanaged Provider Driver
  Shows details to use Application Continuity with Autonomous Database with a client using the ODP.NET Unmanaged Provider Driver.