IBM BPM, V8.0.1, All platforms > Administer the IT infrastructure > Manage events > Preventing multiple failed events when a service is unavailable > Storing events
Store-and-forward feature set up
Consider the following information when implementing store-and-forward processing.
Use IBM Integration Designer to configure a store-and-forward qualifier. The store-and-forward qualifier is used to detect when there are problems with a service and prevent multiple failed events from being sent to the failed event manager. When a service becomes unavailable, the first failed event (and possibly more) are sent to the failed event manager. However, subsequent events are stored if the system encounters a service unavailable exception that matches the one set in the store-and-forward qualifier. When the service becomes available again, stored events can be forwarded to the service for processing using the Store and Forward widget in Business Space. Failed events logged before the store was activated can be resubmitted using the failed event manager.
If event sequencing is configured on the same interface or operation as store-and-forward processing, failed events received by the failed event manager (before the store was activated) must be processed before stored messages.
The most common application of the store-and-forward qualifier is to detect when a service is unavailable, but it could be used to detect other problems such as not authorized exceptions by defining different runtime exceptions for the qualifier.
You specify the store-and-forward qualifier on the interface of the component or import. It can be set at the component level or operation level and defined so as to apply to all interfaces of the component, to apply to a specific interface, or on a specific operation.
The store-and-forward qualifier cannot be placed on exports, except SCA exports.
You cannot define a store-and-forward qualifier for synchronous requests.
Store-and-forward asynchronous request processing can be specified on the interfaces of all import bindings.
- When setting up the store-and-forward qualifier on a component or import, keep the following tasks in mind:
- You configure the runtime exceptions.
By default, the runtime exception is the ServiceUnavailableException.
When this exception is received, the store-and-forward functionality activates and IBM BPM begins storing events for future processing. If any other exception except the specified exception is received, the store-and-forward function will not be activated and events are not stored for future processing.
For information about configuring the store-and-forward feature, see Store and forward qualifier.
Consider the following store-and-forward possibilities for a component with two interfaces and two operations on each component.
Behavior of the store-and-forward feature based on qualifier configuration Qualifier settings Store-and-forward behavior If the qualifier is set on the first operation and the failed event is generated by the invocation of the second operation store-and-forward feature is not activated If the qualifier is set on the first operation and the first interface and a failed event is generated by the invocation of the second operation Only the qualifier and properties specified only the first interface take effect. The qualifier and properties specified on the first operation do not take effect. If the qualifier is set on the second operation and a failed event is generated by the invocation of the second operation, but the headers in the event are incorrect and the information for the second operation cannot be found in the headers store-and-forward feature is not activated and a warning is logged If the qualifier is set on the InterfaceSet (for all interfaces) The qualifier on the interfaceSet takes effect even if the headers in the failed event are not correct If the qualifier is set on the first interface and the first operation and a failed event is generated by the invocation of the first operation The qualifier and properties for both the first operation and the first interface take effect. When multiple qualifier properties take effect, then it is an OR operation between the properties.