Thanks Luke. I'll read through that. -J
On Tue, Jan 19, 2016 at 9:21 AM, Luke Steensen < luke.steen...@braintreepayments.com> wrote: > Hi Jason, > > You might find this blog post useful: > > http://www.confluent.io/blog/how-to-choose-the-number-of-topicspartitions-in-a-kafka-cluster/ > > - Luke > > > On Sat, Jan 16, 2016 at 1:30 PM, Jason Williams <jasonjwwilli...@gmail.com > > > wrote: > > > Hi Franco, > > > > Thank you for the info! It is my reading of the docs that adding > > partitions would require manual rebalancing to spread the existing load? > > > > Would it be advisable instead to start out with a partition count that is > > 10x the initial consumer count? For example if we anticipate starting > with > > 5 consumers, use a partition count of 50 or 100. That way we could just > add > > consumers during a load spike and remove them when it passes? > > > > Sorry for all the questions. I just am not able to find a lot of > > information about how folks are handling auto-scaling kind of situations > > like this. > > > > -J > > > > Sent via iPhone > > > > > On Jan 16, 2016, at 10:52, Franco Giacosa <fgiac...@gmail.com> wrote: > > > > > > Hi Jason, > > > > > > You can try to repartition and assign more consumers. > > > > > > *Documentation* > > > "Modifying topics > > > > > > You can change the configuration or partitioning of a topic using the > > same > > > topic tool. > > > To add partitions you can do > > > > > >> bin/kafka-topics.sh --zookeeper zk_host:port/chroot --alter --topic > > > my_topic_name > > > --partitions 40 > > > Be aware that one use case for partitions is to semantically partition > > > data, and adding partitions doesn't change the partitioning of existing > > > data so this may disturb consumers if they rely on that partition. That > > is > > > if data is partitioned by hash(key) % number_of_partitions then this > > > partitioning will potentially be shuffled by adding partitions but > Kafka > > > will not attempt to automatically redistribute data in any way." > > > > > > > > > Franco. > > > > > > > > > > > > 2016-01-16 19:04 GMT+01:00 Jason Williams <jasonjwwilli...@gmail.com>: > > > > > >> Hi Franco, > > >> > > >> Thanks for responding but that doesn't really answer my question. > > >> > > >> The situation described is it I have N partitions and already N > > consumers > > >> in the CG, and then I receive a spike in messages. How is it suggested > > to > > >> handle adding more consumption capacity to deal the spike...since > adding > > >> consumers when I'm already at N will just add idle consumers? > > >> > > >> -J > > >> > > >> > > >> Sent via iPhone > > >> > > >>> On Jan 16, 2016, at 03:21, Franco Giacosa <fgiac...@gmail.com> > wrote: > > >>> > > >>> 1 consumer group can have many partitions, if the consumer group has > 1 > > >>> consumer and there are N partitions, it will consume from N, if you > > have > > >> a > > >>> spike you can add up to N more consumers to that consumer group. > > >>> > > >>> 2016-01-16 11:32 GMT+01:00 Jason Williams <jasonjwwilli...@gmail.com > >: > > >>> > > >>>> Thanks Jens! > > >>>> > > >>>> So assuming you've already paired your partition count to the > consumer > > >>>> count...if you experience a spike in messages and want to spin up > more > > >>>> consumers to add temporary processing capacity, what's the suggested > > >> way to > > >>>> handle this? (since it would seem you can't just add consumers as > they > > >>>> would remain idle...and adding partitions appears to require manual > > >>>> rebalancing). > > >>>> > > >>>> -J > > >>>> > > >>>> Sent via iPhone > > >>>> > > >>>>> On Jan 16, 2016, at 01:54, Jens Rantil <jens.ran...@tink.se> > wrote: > > >>>>> > > >>>>> Hi, > > >>>>> > > >>>>> > > >>>>> You are correct. The others will remain idle. This is why you > > generally > > >>>> want to have at least the same number of partitions as consumers. > > >>>>> > > >>>>> > > >>>>> > > >>>>> > > >>>>> Cheers, > > >>>>> > > >>>>> Jens > > >>>>> > > >>>>> > > >>>>> > > >>>>> > > >>>>> > > >>>>> – > > >>>>> Skickat från Mailbox > > >>>>> > > >>>>> On Sat, Jan 16, 2016 at 2:34 AM, Jason J. W. Williams > > >>>>> <jasonjwwilli...@gmail.com> wrote: > > >>>>> > > >>>>>> Hi, > > >>>>>> I'm trying to make sure I understand this statement in the docs: > > >>>>>> "Each broker partition is consumed by a single consumer within a > > given > > >>>>>> consumer group. The consumer must establish its ownership of a > given > > >>>>>> partition before any consumption can begin." > > >>>>>> If I have: > > >>>>>> * a topic with 1 partition > > >>>>>> * subscribe a consumer group to the topic > > >>>>>> * the consumer group has 10 consumers belonging to it > > >>>>>> Will only 1 consumer of the 10 ever receive messages from the > topic, > > >> and > > >>>>>> the other 9 remain idle? Or does this mean only 1 consumer at a > time > > >>>> from > > >>>>>> the group will be consuming...in a round-robin fashion? > > >>>>>> -J > > >> > > >
