MonitorForFailover Method

Applies To

Description

Registers the failover notification handler of the application.

Usage

OraDatabase.MonitorForFailover FOSink, FOCtx

Arguments

The arguments for the method are:

Arguments	Description
[`in`] `FOSink`	An `IDispatch` interface implementing the `OnFailover` method which is notified in event of a failover.
[`in`] `FOCtx`	Context-specific information that the application wants passed into the `OnFailover` method in the event of a failover.

Remarks

To receive failover notifications, a notification handler must be registered with the MonitorForFailover method. The notification handler must be an automation object (a class module in Visual Basic) that implements the OnFailover method.

The syntax of the method is:

Public Function OnFailover(Ctx As Variant, fo_type As Variant,fo_event as Variant, fo_OraDB as Variant)

Variants	Description
`[in]` `Ctx`	Passed into the `MonitorForFailover` method by the application. Context-sensitive information that the application wants passed in event of a failover.
`[in]` `fo_type`	`Failover` type. This is the type of failover that the client has requested. The values are: `OO4O_FO_SESSION` indicates only session failover requested. `OO4O_FO_SELECT` indicates select failover and session failover requested.
`[in]` `fo_event`	`Failover` event. This indicates the state of the failover. It has several possible values: `OO4O_FO_BEGIN` indicates that failover has detected a lost connection and failover is starting. `OO4O_FO_END` indicates successful completion of a failover. `OO4O_FO_ABORT` indicates that a failover was unsuccessful, and there is no option of retrying. `OO4O_FO_ERROR` indicates that a failover was unsuccessful, and gives the application the opportunity to handle the error and retry the failover. The application can retry the failover, by programming the `OnFailover` method to return `OO4O_FO_RETRY`. `OO4O_FO_REAUTH` indicates that a user handle has been reauthenticated. This applies to the situation where a client has multiple user sessions on a single database connection. During the initial failover, only the active user session is failed over. Other sessions are failed over when the application tries to use them. This is the value passed to the callback during these subsequent failovers.
`[in]` `fo_OraDB`	The `OraDatabase` object of the user session that is being failed over. Valid only when the `fo_event` variant is `OO4O_FO_REAUTH`.

Examples

Failover Notification Example

See Example: Failover Notification.