With ack=1, some acked msgs could be lost when the leader of a partition changes.
Thanks, Jun On Tue, Sep 9, 2014 at 6:22 AM, Andrew Otto <ao...@wikimedia.org> wrote: > > (2) > > configure enough retries + backoff time in the producer (so that new > > leaders can be elected during failure). > Ya, I’ve been doing this, I need to get it just right. > > > (1) use ack=-1 in the producer; > We use ack=1. If I configure (2) properly, I shouldn’t need ack=-1, will > I? I don’t think this will help me in my case anyway, as it is the > producers themselves that are dropping the messages when their buffers fill > up, while they are waiting for acks on messages before the new leadership > metadata has been propagated. > > Anyway, my question is about being able to test if I have done (2) > properly. Right now > > > > On Sep 9, 2014, at 12:10 AM, Jun Rao <jun...@gmail.com> wrote: > > > To avoid data loss, you will need to (1) use ack=-1 in the producer; (2) > > configure enough retries + backoff time in the producer (so that new > > leaders can be elected during failure). > > > > For controlled failure, you can reduce the unavailability window by using > > controlled shutdown. See > > http://kafka.apache.org/documentation.html#basic_ops_restarting > > > > Thanks, > > > > Jun > > > > On Wed, Sep 3, 2014 at 11:48 AM, Andrew Otto <ao...@wikimedia.org> > wrote: > > > >> Hiya, > >> > >> During leader changes, we see short periods of message loss on some of > our > >> higher volume producers. I suspect that this is because it takes a > couple > >> of seconds for Zookeeper to notice and notify the producers of the > metadata > >> change. During this time, producer buffers can fill up and end up > dropping > >> some messages. > >> > >> I’d like to do some troubleshooting. Is it possible to manually change > >> the leadership of a single partition? I see here[1] that I can start a > >> leadership election for a particular partition, but the JSON doesn’t > show a > >> way to choose the new leader of the partition. > >> > >> Thanks! > >> -Andrew Otto > >> > >> [1] > >> > https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools#Replicationtools-Howtousethetool?.1 > >
