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From Kamal C <kamaltar...@gmail.com>
Subject Re: Consumer Client - How to simulate heartbeats ?
Date Mon, 18 Apr 2016 13:31:46 GMT
When a new consumer joins to the group, it should start to read data
from where the other consumer left.

--Kamal

On Mon, Apr 18, 2016 at 6:58 PM, Florian Hussonnois <fhussonnois@gmail.com>
wrote:

> Thank you very much, the example is really helpful.
>
> My last question is : Why is it necessay to seek the consumer offsets into
> the onPartitionsAssigned method ?
>
>
> https://github.com/omkreddy/kafka-examples/blob/master/consumer/src/main/java/kafka/examples/consumer/advanced/AdvancedConsumer.java#L120
>
> 2016-04-15 15:06 GMT+02:00 Kamal C <kamaltarget@gmail.com>:
>
> > Hi Florian,
> >
> > This may be helpful
> >
> >
> https://github.com/omkreddy/kafka-examples/blob/master/consumer/src/main/java/kafka/examples/consumer/advanced/AdvancedConsumer.java
> >
> > --Kamal
> >
> > On Fri, Apr 15, 2016 at 2:57 AM, Jason Gustafson <jason@confluent.io>
> > wrote:
> >
> > > Hi Florian,
> > >
> > > It's actually OK if processing takes longer than the heartbeat
> interval,
> > > but it does need to finish before the session timeout expires or the
> > > consumer will be kicked out of the group (which typically is revealed
> by
> > > commit failures). If the problem is just that the consumer is handling
> > too
> > > many messages at once, then Kafka 0.10 has an option to tune the number
> > of
> > > messages returned from poll() (max.poll.records), which may be helpful.
> > We
> > > also have a pause/resume API which allows you to call poll() without
> > > consuming any data. That's the best option at the moment for 0.9
> > consumers.
> > >
> > > For what it's worth, we've considered several times adding a
> heartbeat()
> > > API, but the challenge is figuring out how to handle rebalancing.
> > > Underneath the covers, we use heartbeats to find out when the group is
> > > rebalancing, so a heartbeat() option would probably have to return a
> flag
> > > indicating whether a rebalance was needed. If the group has begun
> > > rebalancing, then you would need to call poll() before the expiration
> of
> > > the session timeout so that the consumer can join the rebalance.
> > > Alternatively, we could let heartbeat() complete the rebalance itself,
> > but
> > > then you'd have to be prepared to abort processing from the rebalance
> > > callback. That's not really different from calling poll() after pausing
> > > partitions though. The main problem in any case is that once a
> rebalance
> > > begins, you have the duration of the session timeout to stop processing
> > and
> > > join the rebalance. We're seeing this problem pop up pretty much
> > everywhere
> > > that the consumer is used, so we're trying to think of some better
> > options
> > > to handle it.
> > >
> > > Thanks,
> > > Jason
> > >
> > >
> > > On Thu, Apr 14, 2016 at 12:32 PM, Florian Hussonnois <
> > > fhussonnois@gmail.com>
> > > wrote:
> > >
> > > > Hi everyone,
> > > >
> > > > I have a use case where a message can take longer than '
> > > > heartbeat.interval.ms' to be processed by my application. As I
> > > understand
> > > > the heartbeats of consumer are done while the poll method is invoked.
> > > >
> > > > I would like to instantiate a worker thread to process the messages
> > but I
> > > > need to wait for the messages completion before polling again.
> > > >
> > > > Is there a way to force the consumer to make an heartbeat without
> > polling
> > > > new messages ?
> > > >
> > > > Thanks,
> > > >
> > > > --
> > > > Florian HUSSONNOIS
> > > >
> > >
> >
>
>
>
> --
> Florian HUSSONNOIS
>

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