We're using the bulk index REST api to insert and index new documents. Our configuration is that we have 3 ES instances running as 1 cluster and then n clients sending the bulk index request (where n can be, say 10). Each client will only send one request at a time and waits for either 1000 documents or 1 second, whatever comes first. No further request is sent from each client until a successful response for the bulk index is received from ES. Requests are also sent on a round-robin basis from each client. The clients know nothing of each other's activities.
Our assumption is that ES will not respond successfully if it cannot handle the request i.e. we're assuming that none of the documents will be dropped on the floor. Successful responses therefore signal flow control.
Is this assumption correct?
Thanks in advance.