kafka-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Guozhang Wang <wangg...@gmail.com>
Subject Re: Partial Message Read by Consumer
Date Wed, 11 Dec 2013 16:31:38 GMT
Casey,

Just to confirm, you saw a partial message output from the iterator.next()
call, not from the consumer's fetch response, correct?

Guozhang


On Wed, Dec 11, 2013 at 8:14 AM, Jun Rao <junrao@gmail.com> wrote:

> Have you looked at
>
> https://cwiki.apache.org/confluence/display/KAFKA/FAQ#FAQ-Myconsumerseemstohavestopped%2Cwhy%3F
> ?
> If that doesn't help, could you file a jira and attach your log?
> Apache
> mailing list doesn't support attachments.
>
> Thanks,
>
> Jun
>
>
> On Wed, Dec 11, 2013 at 6:15 AM, Sybrandy, Casey <
> Casey.Sybrandy@six3systems.com> wrote:
>
> > Hello,
> >
> > No, the entire log file isn't bigger than that buffer size and this is
> > occurring while trying to retrieve the first message on the topic, not
> the
> > last.
> >
> > I attached a log.  Line 408 (******** Iterating.) is where we get an
> > iterator and start iterating over the data.  There should be subsequent
> log
> > entries displaying a filename, but they never appear after that point.
> >
> > Some other thoughts:
> >
> > * Network latency is a non-issue as everything is installed on a local
> VM.
> > * I tried with both 10 and 100 messages in case I didn't have enough to
> > make it start producing.  No change.  Yes, I do realize this is silly,
> but
> > when nothing else is working, why not give it a try.  It's like adding
> > magical print statements.
> >
> > Hope this helps.  I need it.
> >
> > Casey
> >
> > ________________________________________
> > From: Tom Brown [tombrown52@gmail.com]
> > Sent: Tuesday, December 10, 2013 7:10 PM
> > To: users@kafka.apache.org
> > Subject: Re: Partial Message Read by Consumer
> >
> > Having a partial message transfer over the network is the design of Kafka
> > 0.7.x (I can't speak to 0.8.x, though it may still be).
> >
> > When the request is made, you tell the server the partition number, the
> > byte offset into that partition, and the size of response that you want.
> > The server finds that offset in the partition, and sends N bytes back
> > (where N is the maximum response size specified). The server does not
> > inspect the contents of the reply to ensure that message boundaries line
> up
> > with the response size. This is by design, and the simplicity allows for
> > high throughput, at the cost of higher client complexity. In practice
> this
> > means is that the response often includes a partial message at the end
> > which the client drops. This means that if the response contains a single
> > message is larger than your maximum response size, you will not be able
> to
> > process that message or continue to the next message. Each time you
> request
> > it, it will only send the partial message, and the Kafka client will send
> > the request again.
> >
> > If I understand the high-level consumer configuration, the fetch.size
> > parameter should be what you need to adjust. It's default is 300K, but I
> > see you have it set to roughly 50MB. Is there any chance your message is
> > larger than that?
> >
> > --Tom
> >
> >
> > On Tue, Dec 10, 2013 at 1:52 PM, Guozhang Wang <wangguoz@gmail.com>
> wrote:
> >
> > > Hello Casey,
> > >
> > > What do you mean by "part of a message is being read"? Could you upload
> > the
> > > output and also the log of the consumer here?
> > >
> > > Guozhang
> > >
> > >
> > > On Tue, Dec 10, 2013 at 12:26 PM, Sybrandy, Casey <
> > > Casey.Sybrandy@six3systems.com> wrote:
> > >
> > > > Hello,
> > > >
> > > > First, I'm using version 0.7.2.
> > > >
> > > > I'm trying to read some messages from a broker, but looking at
> > wireshark,
> > > > it appears that only part of a message is being read by the consumer.
> > > >  After that, no other data is read and I can verify that there are 10
> > > > messages on the broker.  I have the consumer configured as follows:
> > > >
> > > > kafka.zk.connectinfo=127.0.0.1
> > > > kafka.zk.groupid=foo3
> > > > kafka.topic=...
> > > > fetch.size=52428800
> > > > socket.buffersize=524288
> > > >
> > > > I only set socket.buffersize today to see if it helps.  Any help
> would
> > be
> > > > great because this is baffling, especially since this only started
> > > > happening yesterday.
> > > >
> > > > Casey Sybrandy MSWE
> > > > Six3Systems
> > > > Cyber and Enterprise Systems Group
> > > > www.six3systems.com
> > > > 301-206-6000 (Office)
> > > > 301-206-6020 (Fax)
> > > > 11820 West Market Place
> > > > Suites N-P
> > > > Fulton, MD. 20759
> > > >
> > >
> > >
> > >
> > > --
> > > -- Guozhang
> > >
> >
>



-- 
-- Guozhang

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message