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From David Yu <david...@optimizely.com>
Subject Re: Samza not consuming
Date Fri, 18 Mar 2016 02:56:12 GMT
Looks like this has nothing to do with checkpointing. Our samza job has an
issue communicating an external service, which left the particular
process() call waiting indefinitely. And it doesn't look like samza has a
way to timeout a processing cycle.

On Thu, Mar 17, 2016 at 5:42 PM, David Yu <david.yu@optimizely.com> wrote:

> Strangely, I was not able to get checkpoint value for one particular
> partition. Could this cause the job to be stuck?
>
> On Thu, Mar 17, 2016 at 5:23 PM, David Yu <david.yu@optimizely.com> wrote:
>
>> Hi, I wanna resurface this thread because I'm still facing issues with
>> our samza not receiving events.
>>
>> Our samza job metric "SamzaContainerMetrics.process-calls" dropped to
>> zero today again. So does "SamzaContainerMetrics.process-envelopes" (of
>> course). Current topic offset and task checkpoint revealed that everything
>> looks good:
>>
>> Topic partition 18 offset (as of now) = *488986*
>> Current checkpoint for taskname Partition 18: tasknames.Partition
>> 18.systems.kafka.streams.nogoalids.partitions.18 = *474222*
>>
>> Even after redeployment of the job, everything still seemed stuck :(
>>
>> Any ideas that could help me debug this will be appreciated.
>>
>>
>> On Wed, Mar 16, 2016 at 4:19 PM, David Yu <david.yu@optimizely.com>
>> wrote:
>>
>>> No, instead, I updated the checkpoint topic with the "upcoming" offsets.
>>> (I should have done a check before that though).
>>>
>>> So a related question: if I delete the checkpoint topic from Kafka, that
>>> would essentially clear up all the offset info and samza will be able to
>>> recreate this topic with the latest offsets (e.g. smallest). Is that
>>> correct? Just wanna find an easy way to do a "reprocess all" kind of
>>> operation.
>>>
>>> Thanks.
>>>
>>> On Wed, Mar 16, 2016 at 3:25 PM, Navina Ramesh <
>>> nramesh@linkedin.com.invalid> wrote:
>>>
>>>> Strange. I am unable to comment on the behavior because I don't know
>>>> what
>>>> your checkpoints looked like in the checkpoint topic.
>>>>
>>>> Did you try reading the checkpoint topic log ?
>>>>
>>>> If you setting systems.kafka.streams.nogoalids.samza.reset.offset =
>>>> true,
>>>> you are essentially ignoring checkpoints for that stream. Do verify that
>>>> you are reading from the correct offset in the stream :)
>>>>
>>>> Thanks!
>>>> Navina
>>>>
>>>> On Wed, Mar 16, 2016 at 3:16 PM, David Yu <david.yu@optimizely.com>
>>>> wrote:
>>>>
>>>> > Finally seeing events flowing again.
>>>> >
>>>> > Yes, the "systems.kafka.consumer.auto.offset.reset" option is
>>>> probably not
>>>> > a factor here. And yes, I am using checkpointing (kafka). Not sure if
>>>> the
>>>> > offsets are messed up. But I was able to use
>>>> > "systems.kafka.streams.nogoalids.samza.reset.offset=true" to reset the
>>>> > offsets to the newest ones. After that, events started coming. Still,
>>>> it is
>>>> > unclear to me how things got stuck in the first place.
>>>> >
>>>> > On Wed, Mar 16, 2016 at 2:31 PM, Navina Ramesh
>>>> > <nramesh@linkedin.com.invalid
>>>> > > wrote:
>>>> >
>>>> > > HI David,
>>>> > > This configuration you have tweaked
>>>> > > (systems.kafka.consumer.auto.offset.reset) is honored only when
one
>>>> of
>>>> > the
>>>> > > following condition holds:
>>>> > > * topic doesn't exist
>>>> > > * checkpoint is older than the maximum message history retained
by
>>>> the
>>>> > > brokers
>>>> > >
>>>> > > So, my questions are :
>>>> > > Are you using checkpointing? If you do, you can read the checkpoint
>>>> topic
>>>> > > to see the offset that is being used to fetch data.
>>>> > >
>>>> > > If you are not using checkpoints, then samza uses
>>>> > > systems.kafka.samza.offset.default to decide whether to start
>>>> reading
>>>> > from
>>>> > > the earliest (oldest data) or upcoming (newest data) offset in
the
>>>> > stream.
>>>> > >
>>>> > > This could explain from where your job is trying to consume and
you
>>>> can
>>>> > > cross-check with the broker.
>>>> > > For the purpose of debugging, you can print a debug line in
>>>> process()
>>>> > > method to print the offset of the message you are processing
>>>> > > (message.getOffset). Please remember to remove the debug line after
>>>> > > troubleshooting. Else you risk filling up your logs.
>>>> > >
>>>> > > Let me know if you have more questions.
>>>> > >
>>>> > > Thanks!
>>>> > > Navina
>>>> > >
>>>> > > On Wed, Mar 16, 2016 at 2:12 PM, David Yu <david.yu@optimizely.com>
>>>> > wrote:
>>>> > >
>>>> > > > I'm trying to debug our samza job, which seem to be stuck
from
>>>> > consuming
>>>> > > > from our Kafka stream.
>>>> > > >
>>>> > > > Every time I redeploy the job, only the same handful of events
get
>>>> > > > consumed, and then no more events get processed. I manually
>>>> checked to
>>>> > > make
>>>> > > > sure the input stream is live and flowing. I also tried both
the
>>>> > > following:
>>>> > > >
>>>> > > > systems.kafka.consumer.auto.offset.reset=largest
>>>> > > > systems.kafka.consumer.auto.offset.reset=smallest
>>>> > > >
>>>> > > > I'm also seeing the following from the log:
>>>> > > >
>>>> > > > ... partitionMetadata={Partition
>>>> > > > [partition=0]=SystemStreamPartitionMetadata [oldestOffset=144907,
>>>> > > > newestOffset=202708, upcomingOffset=202709], Partition
>>>> > > > [partition=5]=SystemStreamPartitionMetadata [oldestOffset=140618,
>>>> > > > newestOffset=200521, upcomingOffset=200522], ...
>>>> > > >
>>>> > > >
>>>> > > > Not sure what other ways I could diagnose this problem. Any
>>>> suggestion
>>>> > is
>>>> > > > appreciated.
>>>> > > >
>>>> > >
>>>> > >
>>>> > >
>>>> > > --
>>>> > > Navina R.
>>>> > >
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> Navina R.
>>>>
>>>
>>>
>>
>

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