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Kafka >> mail # user >> who is using kafka to stare large messages?


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Re: who is using kafka to stare large messages?
Neha,

Does the broker store messages compressed, even if the producer doesn't
compress them when sending them to the broker?

Why does the broker re-compress message batches?  Does it not have enough
info from the producer request to know the number of messages in the batch?

Jason
On Mon, Oct 7, 2013 at 12:40 PM, Neha Narkhede <[EMAIL PROTECTED]>wrote:

> the total message size of the batch should be less than
> message.max.bytes or is that for each individual message?
>
> The former is correct.
>
> When you batch, I am assuming that the producer sends some sort of flag
> that this is a batch, and then the broker will split up those messages to
> individual messages and store them in the log correct?
>
> The broker splits the compressed message into individual messages to assign
> the logical offsets to every message, but the data is finally stored
> compressed and is delivered in the compressed format to the consumer.
>
> Thanks,
> Neha
>
>
> On Mon, Oct 7, 2013 at 9:26 AM, S Ahmed <[EMAIL PROTECTED]> wrote:
>
> > When you batch things on the producer, say you batch 1000 messages or by
> > time whatever, the total message size of the batch should be less than
> > message.max.bytes or is that for each individual message?
> >
> > When you batch, I am assuming that the producer sends some sort of flag
> > that this is a batch, and then the broker will split up those messages to
> > individual messages and store them in the log correct?
> >
> >
> > On Mon, Oct 7, 2013 at 12:21 PM, Neha Narkhede <[EMAIL PROTECTED]
> > >wrote:
> >
> > > The message size limit is imposed on the compressed message. To answer
> > your
> > > question about the effect of large messages - they cause memory
> pressure
> > on
> > > the Kafka brokers as well as on the consumer since we re-compress
> > messages
> > > on the broker and decompress messages on the consumer.
> > >
> > > I'm not so sure that large messages will have a hit on latency since
> > > compressing a few large messages vs compressing lots of small messages
> > with
> > > the same content, should not be any slower. But you want to be careful
> on
> > > the batch size since you don't want the compressed message to exceed
> the
> > > message size limit.
> > >
> > > Thanks,
> > > Neha
> > >
> > >
> > > On Mon, Oct 7, 2013 at 9:10 AM, S Ahmed <[EMAIL PROTECTED]> wrote:
> > >
> > > > I see, so that is one thing to consider is if I have 20 KB messages,
> I
> > > > shouldn't batch too many together as that will increase latency and
> the
> > > > memory usage footprint on the producer side of things.
> > > >
> > > >
> > > > On Mon, Oct 7, 2013 at 11:55 AM, Jun Rao <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > At LinkedIn, our message size can be 10s of KB. This is mostly
> > because
> > > we
> > > > > batch a set of messages and send them as a single compressed
> message.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Jun
> > > > >
> > > > >
> > > > > On Mon, Oct 7, 2013 at 7:44 AM, S Ahmed <[EMAIL PROTECTED]>
> > wrote:
> > > > >
> > > > > > When people using message queues, the message size is usually
> > pretty
> > > > > small.
> > > > > >
> > > > > > I want to know who out there is using kafka with larger payload
> > > sizes?
> > > > > >
> > > > > > In the configuration, the maximum message size by default is set
> > to 1
> > > > > > megabyte (
> > > > > > message.max.bytes1000000)
> > > > > >
> > > > > > My message sizes will be probably be around 20-50 KB but to me
> that
> > > is
> > > > > > large for a message payload so I'm wondering what effects that
> will
> > > > have
> > > > > > with kafka.
> > > > > >
> > > > >
> > > >
> > >
> >
>