Hello all. I'm developing a kafka client and have a question about kafka server guarantees.
A statement from https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol#AGuideToTheKafkaProtocol-Network makes me a bit confused: "The server guarantees that on a single TCP connection, requests will be processed in the order they are sent and responses will return in that order as well. The broker's request processing allows only a single in-flight request per connection in order to guarantee this ordering. Note that clients can (and ideally should) use non-blocking IO to implement request pipelining and achieve higher throughput. i.e., clients can send requests even while awaiting responses for preceding requests since the outstanding requests will be buffered in the underlying OS socket buffer. All requests are initiated by the client, and result in a corresponding response message from the server except where noted." Does this mean that when a client is sending more than one in-flight request per connection, the server does not guarantee that responses will be sent in the same order as requests? In other words, if I have a strictly monotonically increasing integer as a correlation id for all requests, can I rely on Kafka that correlation id in responses will also have this property? Thanks. /Ivan
