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Kafka >> mail # user >> Re: ordering


No, there isn't, not at the very start when there is no state in
Zookeeper. Once there is state the Kafka team have told me that
rebalancing will not result in any dupes.

However, if there is no state in Zookeeper and your partitions are
empty, simply wait until all consumers have balanced before sending
any data.

Philip

On Wed, Aug 21, 2013 at 12:30 PM, Yu, Libo <[EMAIL PROTECTED]> wrote:
> Hi,
>
> This is from kafka faq:
>
>
>   *   Each partition is not consumed by more than one consumer thread/process in each consumer group. This allows to have each process consume in a single threaded fashion to guarantee ordering to the consumer within the partition (if we split up a partition of ordered messages and handed them out to multiple consumers even though the messages were stored in order they would be processed out of order at times).
>
> Is this doable?
>
> Say a topic has 3 partitions. And there are 3 consumer processes in a consumer group each of which has a single thread.
> When we start the 3 processes, when the first process is up, it will consume all 3 partitions. When the second process is up,
> 1 process consumes 2 partitions and 1 consumes 1 partition. Only when the third process is up, will each process consume
> One partition. This will cause trouble. There seems to be no way to bound a stream to one partition.
>
>
> Regards,
>
> Libo
>

 
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB