Syncronous/Asyncronous Mode
As described in Request Queue Management, a client that sends multiple requests before waiting for the response from a previous request is not guaranteed to receive the responses in the order they were sent.
If a client wishes to send a request before waiting for
the response to the previous one (asyncronous mode), then the client must
populate the
id
attribute in the request with a
transaction ID value that will be passed back in the response. The
id
attribute needs to be unique enough
to the client to correlate a response to a request that was sent. The XML Data
server will return the id passed in the response.
If a client wishes to send a single request and wait for
the response before sending another one (syncronous mode), then the client does
not need to populate the
id
attribute in the request, because the
response will always be for the request last sent. The
id
attribute can be populated if
desired, and it will be passed back in the response just as in asyncronous
mode.