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Jun Rao commented on KAFKA-955: ------------------------------- Thanks for patch v7. A couple of more comments. 70. There is a long standing bug in ProducerRequest.handleError(). If ack=0, we shouldn't send a response when the broker hits an unexpected error. We should either close the socket connection or send no response. Not sure which one is better. 71. A minor issue. The following comment in RequestChannel is a bit confusing. It sounds like that it needs to read more data from network to complete this request, but it is not. /** No operation to take for the request, need to read more over the network */ def noOperation(processor: Int, request: RequestChannel.Request) { > After a leader change, messages sent with ack=0 are lost > -------------------------------------------------------- > > Key: KAFKA-955 > URL: https://issues.apache.org/jira/browse/KAFKA-955 > Project: Kafka > Issue Type: Bug > Affects Versions: 0.8 > Reporter: Jason Rosenberg > Assignee: Guozhang Wang > Fix For: 0.8 > > Attachments: KAFKA-955.v1.patch, KAFKA-955.v1.patch, > KAFKA-955.v2.patch, KAFKA-955.v3.patch, KAFKA-955.v4.patch, > KAFKA-955.v5.patch, KAFKA-955.v6.patch, KAFKA-955.v7.patch > > > If the leader changes for a partition, and a producer is sending messages > with ack=0, then messages will be lost, since the producer has no active way > of knowing that the leader has changed, until it's next metadata refresh > update. > The broker receiving the message, which is no longer the leader, logs a > message like this: > Produce request with correlation id 7136261 from client on partition > [mytopic,0] failed due to Leader not local for partition [mytopic,0] on > broker 508818741 > This is exacerbated by the controlled shutdown mechanism, which forces an > immediate leader change. > A possible solution to this would be for a broker which receives a message, > for a topic that it is no longer the leader for (and if the ack level is 0), > then the broker could just silently forward the message over to the current > leader. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira