How Asynchronous Processing Works
A client/server operation normally involves a request and a response. The client issues the request to a server to start a database operation; in response, the server reports success or failure to the client and returns any relevant data.
When an application submits a request to a remote database, several seconds may elapse before the application receives a response. Under traditional synchronous processing, the application cannot perform any functions while it is waiting for the response. However, under asynchronous processing, the application can issue a request and then perform functions that do not require knowledge about the response. For example, it can update a window in OpenROAD or update a log file. This enables the application to maximize efficiency during the period between a request and response.
When the application completes its non-database operations, it returns control to OpenAPI, using the IIapi_wait() function to complete the database request.
More information: