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From tao xiao <xiaotao...@gmail.com>
Subject Re: New consumer not fetching as quickly as possible
Date Wed, 02 Dec 2015 03:43:51 GMT
Hi Jason,

You are correct. I initially produced 10000 messages in Kafka before I
started up my consumer with auto.offset.reset=earliest. But like I said the
majority number of first 10 polls returned 0 message and the lag remained
above 0 which means I still have enough messages to consume.  BTW I commit
offset manually so the lag should accurately reflect how many messages
remaining.

I will turn on debug logging and test again.

On Wed, 2 Dec 2015 at 07:17 Jason Gustafson <jason@confluent.io> wrote:

> Hey Tao, other than high latency between the brokers and the consumer, I'm
> not sure what would cause this. Can you turn on debug logging and run
> again? I'm looking for any connection problems or metadata/fetch request
> errors. And I have to ask a dumb question, how do you know that more
> messages are available? Are you monitoring the consumer's lag?
>
> -Jason
>
> On Tue, Dec 1, 2015 at 10:07 AM, Gerard Klijs <gerard.klijs@dizzit.com>
> wrote:
>
> > Thanks Tao, it worked.
> > I also played around with my test setting trying to replicate your
> results,
> > using default settings. But als long as the poll timeout is set to 100ms
> or
> > larger the only time-out I get are near the start and near the end (when
> > indeed there is nothing to consume). This is with a producer putting out
> > 1000 messages a second. Maybe the load of the producer your using is not
> > constant? Maybe you could run a test with the
> > org.apache.kafka.tools.ProducerPerformance class to see if it makes a
> > difference?
> >
> > On Tue, Dec 1, 2015 at 11:35 AM tao xiao <xiaotao183@gmail.com> wrote:
> >
> > > Gerard,
> > >
> > > In your case I think you can set fetch.min.bytes=1 so that the server
> > will
> > > answer the fetch request as soon as a single byte of data is available
> > > instead of accumulating enough messages.
> > >
> > > But in my case is I have plenty of messages in broker and I am sure the
> > > size of total message are much larger than the default setting which is
> > > 1024 bytes but still the consumer doesn't return messages for every
> poll.
> > >
> > >
> > > On Tue, 1 Dec 2015 at 18:29 Gerard Klijs <gerard.klijs@dizzit.com>
> > wrote:
> > >
> > > > I was experimenting with the timeout setting, but as long as messages
> > are
> > > > produced and the consumer(s) keep polling I saw little difference. I
> > did
> > > > see for example that when producing only 1 message a second, still it
> > > > sometimes wait to get three messages. So I also would like to know if
> > > there
> > > > is a faster way.
> > > >
> > > > On Tue, Dec 1, 2015 at 10:35 AM tao xiao <xiaotao183@gmail.com>
> wrote:
> > > >
> > > > > Hi team,
> > > > >
> > > > > I am using the new consumer with broker version 0.9.0. I notice
> that
> > > > > poll(time) occasionally returns 0 message even though I have enough
> > > > > messages in broker. The rate of returning 0 message is quite high
> > like
> > > 4
> > > > > out of 5 polls return 0 message. It doesn't help by increasing the
> > poll
> > > > > timeout from 300ms to 1 second. are there any configurations that
I
> > can
> > > > > tune to fetch  data as quickly as possible?
> > > > >
> > > > > Both consumer and broker configs are default
> > > > >
> > > >
> > >
> >
>

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