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From Prabhu V <vpra...@gmail.com>
Subject Re: Kakfa batches
Date Wed, 03 Aug 2016 13:40:10 GMT
Thanks for the reply.

Yeah I mean a manual commit in #3, this is because in this case the offsets
would accurately reflect the number of messages processed.

My understanding is that the current checkpointing process commits the
state of all the operators separately, the kafka connector will commit
offset X while the window operator will checkpoint the messages with offset
range  (X - N upto X). If the job fails now (yarn application failed due to
some network issue, someone accidentally killed my yarn job etc) the
restarting the job will start processing from offset X and messages that
were checkpointed by the window operator are lost.

The reason we need the accuracy is because the down stream processes are
batch oriented (typically process a 15 min bucket of data) and are
triggered based on message timestamps exceeding a certain watermark. We
have a separate store that maintains the relation between partition-offset
and message-timestamp (these are ever increasing values). A check happens
against this store to see if the offsets processed by flink job has crossed
a certain timestamp.



On Wed, Aug 3, 2016 at 6:19 AM, Ufuk Celebi <uce@apache.org> wrote:

> On Wed, Aug 3, 2016 at 2:07 PM, Prabhu V <vprabhu@gmail.com> wrote:
> > Obeservations with Streaming.
> >
> > 1) Long running kerberos fails in 7 days (the data that is held in the
> > window buffer is lost and restart results in event loss)
>
> This is a known issue I think. Looping in Max who knows the details I
> think.
>
> > 2) I hold on to the resouces/container in the cluster irrespective of
> volume
> > of events for all time
>
> Correct. There are plans for Flink 1.2 to make this dynamic.
>
> > Is there a way the kafkaconnector can take a start and stop values for
> > offsets that would be ideal for my scenario. The design in this scenario
> > would be to...
>
> This is not possible at the moment. What do you mean with "3) commit
> the offsets after job is successful"? Do you want to manually do this?
>

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