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Kafka, mail # user - Kafka wiki Documentation conventions - looking for feedback


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Chris Curtin 2013-03-25, 12:03
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Chris Curtin 2013-03-29, 15:28
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Jun Rao 2013-04-22, 16:27
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Chris Curtin 2013-04-22, 17:41
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Jun Rao 2013-04-22, 22:12
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Jun Rao 2013-04-29, 04:51
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Chris Curtin 2013-04-29, 12:55
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Jun Rao 2013-04-29, 15:03
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Chris Curtin 2013-04-29, 15:17
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Jun Rao 2013-04-29, 15:58
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Re: Kafka wiki Documentation conventions - looking for feedback
Chris Curtin 2013-04-29, 18:19
Thanks, I missed that the addition of consumers can cause a re-balance.
Thought it was only on Leader changes.

I've updated the wording in the example.

I'll pull down the beta and test my application then change the names on
the properties.

Thanks,

Chris
On Mon, Apr 29, 2013 at 11:58 AM, Jun Rao <[EMAIL PROTECTED]> wrote:

> Basically, every time a consumer joins a group, every consumer in the
> groups gets a ZK notification and each of them tries to own a subset of the
> total number of partitions. A given partition is only assigned to one of
> the consumers in the same group. Once the ownership is determined, each
> consumer consumes messages coming from its partitions and manages the
> offset of those partitions. Since at any given point of time, a partition
> is only owned by one consumer, there won't be conflicts on updating the
> offsets. More details are described in the "consumer rebalancing algorithm"
> section of http://kafka.apache.org/07/design.html
>
> Thanks,
>
> Jun
>
>
> On Mon, Apr 29, 2013 at 8:16 AM, Chris Curtin <[EMAIL PROTECTED]
> >wrote:
>
> > Jun, can you explain this a little better? I thought when using Consumer
> > Groups that on startup Kafka connects to ZooKeeper and finds the last
> read
> > offset for every partition in the topic being requested for the group.
> That
> > is then the starting point for the consumer threads.
> >
> > If a second process starts while the first one is running with the same
> > Consumer Group, won't the second one read the last offsets consumed by
> the
> > already running process and start processing from there? Then as the
> first
> > process syncs consumed offsets, won't the 2nd process's next update
> > overwrite them?
> >
> > Thanks,
> >
> > Chris
> >
> >
> >
> >
> > On Mon, Apr 29, 2013 at 11:03 AM, Jun Rao <[EMAIL PROTECTED]> wrote:
> >
> > > Chris,
> > >
> > > Thanks for the writeup. Looks great overall. A couple of comments.
> > >
> > > 1. At the beginning, it sounds like that one can't run multiple
> processes
> > > of consumers in the same group. This is actually not true. We can
> create
> > > multiple instances of consumers for the same group in the same JVM or
> > > different JVMs. The consumers will auto-balance among themselves.
> > >
> > > 2. We have changed the name of some config properties.
> > > auto.commit.interval.ms is correct. However, zk.connect,
> > > zk.session.timeout.ms and zk.sync.time.ms are changed to
> > > zookeeper.connect,
> > > zookeeper.session.timeout.ms, and zookeeper.sync.time.ms,
> respectively.
> > >
> > > I will add a link to your wiki in our website.
> > >
> > > Thanks again.
> > >
> > > Jun
> > >
> > >
> > > On Mon, Apr 29, 2013 at 5:54 AM, Chris Curtin <[EMAIL PROTECTED]
> > > >wrote:
> > >
> > > > Hi Jun,
> > > >
> > > > I finished and published it this morning:
> > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Consumer+Group+Example
> > > >
> > > > One question: when documenting the ConsumerConfig parameters I
> couldn't
> > > > find a description for the 'auto.commit.interval.ms' setting. I
> found
> > > one
> > > > for 'autocommit.interval.ms' (no '.' between auto and commit) in the
> > > > Google
> > > > Cache only. Which spelling is it? Also is my description of it
> correct?
> > > >
> > > > I'll take a look at custom encoders later this week. Today and
> Tuesday
> > > are
> > > > going to be pretty busy.
> > > >
> > > > Please let me know if there are changes needed to the High Level
> > Consumer
> > > > page.
> > > >
> > > > Thanks,
> > > >
> > > > Chris
> > > >
> > > >
> > > > On Mon, Apr 29, 2013 at 12:50 AM, Jun Rao <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > Chris,
> > > > >
> > > > > Any update of the high level consumer example?
> > > > >
> > > > > Also, in the Producer example, it would be useful to describe how
> to
> > > > write
> > > > > a customized encoder. One subtle thing is that the encoder needs a
> > > > > constructor that takes a a single VerifiableProperties argument (

 
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Jun Rao 2013-04-29, 22:18
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Chris Curtin 2013-05-01, 13:56
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Jun Rao 2013-05-01, 15:46
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Chris Curtin 2013-05-01, 19:34
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Jun Rao 2013-05-01, 21:37
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Jun Rao 2013-04-24, 16:26
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Chris Curtin 2013-04-24, 18:12
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Jun Rao 2013-04-25, 04:08