When EAI call-outs are made using synchronous invocation, the iProcess background process is blocked until the EAI call-out has completed. Only one synchronous EAI call-out can be invoked at one time by each BG process i.e. even if you designed a procedure with EAI steps in parallel (see
Creating Procedures with Parallel EAI Steps), each EAI step is processed sequentially in turn. Compare this with asynchronous with reply invocation where you can make simultaneous EAI call-outs when they are in parallel.
This call-out style de-couples the request and response into two separate operations from the iProcess background process: the initiation of the call-out and the “get reply” of the call-out. EAI call-outs can be made in parallel (by designing the procedure with parallel EAI steps - see
Creating Procedures with Parallel EAI Steps) and they will all be invoked. The call-out is initiated for all parallel EAI steps before the BG waits for a reply from the first to complete. If the replying step is immediate release, its actions are processed before waiting for replies to any other asynchronous with reply call-outs.
