The following table summarizes the connection properties that control how failover works with the driver.

See "Using failover" and "Using client load balancing" for overviews of failover and client load balancing.

Table 1. Summary: Failover Properties for the Oracle Driver
Property Characteristic

AlternateServers

 One or multiple alternate database servers. An IP address or server name identifying each server is required. Port number and the ServiceName or SID connection properties are optional. If the port number is unspecified, the port specified for the primary server is used. If a port number is not specified for the primary server, the default port number of 1521 is used.

ConnectionRetryCount

 Number of times the driver retries the primary database server, and if specified, alternate servers until a successful connection is established.

If set to 0, the driver does not try to reconnect after the initial unsuccessful attempt.

If set to x, the driver retries connection attempts the specified number of times. If a connection is not established during the retry attempts, the driver returns an exception that is generated by the last database server to which it tried to connect.

The default is 5.

ConnectionRetryDelay

 Wait interval, in seconds, between connection retry attempts when the ConnectionRetryCount property is set to a positive integer.

If set to 0, the driver does not delay between retries.

If set to x, the driver waits between connection retry attempts the specified number of seconds.

The default is 1.

FailoverGranularity

 Determines whether the driver fails the entire failover process or continues with the process if exceptions occur while trying to reestablish a lost connection.

If set to nonAtomic, the driver continues with the failover process and posts any exceptions on the statement on which they occur.

If set to atomic, the driver fails the entire failover process if an exception is generated as the result of restoring the state of the connection. The driver stops trying to connect to an alternative server and returns an exception indicating that the connection was lost. If an exception is generated as a result of restoring the state of work in progress by re-executing the Select statement, the driver continues with the failover process, but generates an exception warning that the Select statement must be reissued.

If set to atomicWithRepositioning, the driver fails the entire failover process if any exception is generated as the result of restoring the state of the connection or the state of work in progress. The driver stops trying to connect to an alternative server and returns an exception indicating that the connection was lost.

The default is nonAtomic (the driver continues with the failover process and posts any exceptions on the statement on which they occur).

FailoverMode

 The failover method you want the driver to use.

If set to connect, the driver provides failover protection for new connections only.

If set to extended, the driver provides failover protection for new and lost connections, but not any work in progress.

If set to select, the driver provides failover protection for new and lost connections. In addition, it preserves the state of work that is performed by the last Select statement that is executed on the Statement object.

The default is connect (connection failover is used).

FailoverPreconnect

 Specifies whether the driver tries to connect to the primary and an alternate server at the same time.

If set to true, the driver tries to connect to the primary and an alternate server at the same time. This can be useful if your application is time-sensitive and cannot absorb the wait for the failover connection to succeed.

If set to false, the driver tries to connect to an alternate server only when failover is caused by an unsuccessful connection attempt or a lost connection. This value provides the best performance, but your application typically experiences a short wait while the failover connection is attempted.

The default is false (the driver tries to connect to an alternate server only when failover is caused by an unsuccessful connection attempt or a lost connection).

LoadBalancing

 Sets whether the driver will use client load balancing in its attempts to connect to the database servers (primary and alternate). If client load balancing is enabled, the driver uses a random pattern instead of a sequential pattern in its attempts to connect.

The default is false (client load balancing is disabled).

PortNumber

 Specifies the TCP port of the primary database server that is listening for connections to the database.

The default is 1521.

ServerName

 Specifies the name or IP address of the server to which you want to connect.