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3.2.10 Invocation style considerations
This section explains invocation style considerations.
Using asynchronicity judiciously
Components and modules might be wired to each other either synchronously or
asynchronously. The choice of interaction style can have a profound impact on performance.
Exercise care when making this choice.
Setting the Preferred Interaction Style to Synchronous when possible
Many Business Process Manager server component types (such as interface maps or
business rules) start their target components based on the Preferred Interaction Style setting
of the target interface. Because synchronous cross-component invocations perform better,
set the Preferred Interaction Style to Synchronous when possible. Change this setting to
Asynchronous only in specific cases. Such cases might include starting a long-running
business process, or more generally, where the target component requires asynchronous
invocation.
Starting with WebSphere Integration Developer V6.2 (now Integration Designer), when a new
component is added to an assembly diagram, its Preferred Interaction Style is set to
Synchronous, Asynchronous, or Any, based on the component. In previous releases of the
Integration Designer (then called WebSphere Integration Developer), the default initial setting
of Preferred Interaction Style was set to Any unless explicitly changed by the user. If the
Preferred Interaction Style of a component is set to Any, how the component is started is
determined by the caller’s context. If the caller is a long-running business process, a Preferred
Interaction Style setting of Any is treated as asynchronous. If the caller is a non-interruptible
business flow, a Preferred Interaction Style setting of Any is treated as synchronous.
See “Taking advantage of transactional attributes for activities in long-running processes” on
page 39 for more information about the invocation logic of processes
The following list details additional considerations for invocation styles:
► When the Preferred Interaction Style of an interface is set to Asynchronous, it is important
to realize the downstream implications. Any components started downstream inherit the
asynchronous interaction style unless they explicitly set the Preferred Interaction Style to
Synchronous.
► At the input boundary to a module, exports that represent asynchronous transports such
as IBM WebSphere MQ, JMS, or Java EE Connector Architecture (with asynchronous
delivery set), set the interaction style to Asynchronous. This setting can cause
downstream invocations to be asynchronous if the Preferred Interaction Style is Any.
► For an SCA import, you can use Preferred Interaction Style to specify whether the
cross-module call should be Synchronous or Asynchronous.
► For other imports that represent asynchronous transports such as WebSphere MQ or
JMS, it is not necessary to set the Preferred Interaction Style to Asynchronous. Doing so
introduces an unnecessary asynchronous hop between the calling module and the
invocation of the transport.
40 IBM Business Process Manager V8.0 Performance Tuning and Best Practices