Bob, The latency that you are seeing seems a little high. I would suspect at your low write rate, the # of partitions is too high. The simplest test for latency could be one producer, one broker partition and one consumer. It will be great if you can give that a try.
Thanks, Neha On Wed, Nov 7, 2012 at 5:55 PM, Bob Cotton <bcot...@rallydev.com> wrote: > Hello, > > We have a low-volume topic (~75msgs/sec) for which we would like to have a > low propagation delay from producer to consumer. > > We have 3 brokers, each with a default of 4 partitions each. for a total of > 12 partitions. > The producer is sync, without compression. There are 8 producers each > producing 1/8 of the traffic. > We are using the high-level java consumer, with 4 threads consuming the > topic. > > We are wrapping the message with a custom Encoder/Decoder and record > currentTimeMillis() on the sender, and do the same in the receiver, then > record the propagation delay. All hosts are time synced with ntp. > > With the settings on the broker for flush messages and flush interval > (unset, defaults to 500 msgs and 3000ms) the overall 95th percentile for > propagation is 2,500ms. > > When we adjust the topic flush interval to 20ms, the 95th percentile drops > to 1,700ms > When we adjust the consumers "fetcher.backoff.ms" to 10, the 95th > percentile drops to about 970ms. > > We would like this to be sub-500ms. > We could run with less partitions and/or more consumer threads. > > Anything glaring about this config? anything we're missing? > > Thanks > -Bob
