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Kafka >> mail # user >> seeing poor consumer performance in 0.7.2


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Re: seeing poor consumer performance in 0.7.2
Hmm it is highly unlikely that that is the culprit... There is lots of
bandwidth available for me to use. I will definitely keep that in mind
though. I was working on this today and have some tidbits of additional
information and thoughts that you might be able to shed some light on:

   - I mentioned I have 2 consumers, but each consumer is running with 8
   threads for this topic (and each consumer has 8 cores available).
   - When I initially asked for help the brokers were configured with
   num.partitions=1, I've since tried higher numbers (3, 64) and haven't seen
   much of an improvement aside from forcing both consumer apps to handle
   messages (with the overall performance not changing much).
   - I ran into this article
   http://riccomini.name/posts/kafka/2012-10-05-kafka-consumer-memory-tuning/and
tried a variety of options of queuedchunks.max and fetch.size with no
   significant results (simply meaning it did not achieve the goal of me
   constantly processing hundreds or thousands of messages per second, which
   is similar to the rate of input). I would not be surprised if I'm wrong but
   this made me start to think that the problem may lie outside of the
   consumers
   - Would the combination of a high number of partitions (64) and a high
   log.flush.interval (10k) prevent logs from flushing as often as they need
   to for my desired rate of consumption (even with
   log.default.flush.interval.ms=1000?)

Despite the changes I mentioned the behaviour is still the consumers
receiving larger spikes of messages mixed with periods of complete
inactivity and overall a long delay between messages being written and
messages being read (about 2 minutes). Anyway... as always I greatly
appreciate any help.

On Sun, Apr 21, 2013 at 8:50 PM, Jun Rao <[EMAIL PROTECTED]> wrote:

> Is your network shared? Is so, another possibility is that some other apps
> are consuming the bandwidth.
>
> Thanks,
>
> Jun
>
>
> On Sun, Apr 21, 2013 at 12:23 PM, Andrew Neilson <[EMAIL PROTECTED]
> >wrote:
>
> > Thanks very much for the reply Neha! So I swapped out the consumer that
> > processes the messages with one that just prints them. It does indeed
> > achieve a much better rate at peaks but can still nearly zero out (if not
> > completely zero out). I plotted the messages printed in graphite to show
> > the behaviour I'm seeing (this is messages printed per second):
> >
> >
> >
> https://www.dropbox.com/s/7u7uyrefw6inetu/Screen%20Shot%202013-04-21%20at%2011.44.38%20AM.png
> >
> > The peaks are over ten thousand per second and the troughs can go below
> 10
> > per second just prior to another peak. I know that there are plenty of
> > messages available because the ones currently being processed are still
> > from Friday afternoon, so this may or may not have something to do with
> > this pattern.
> >
> > Is there anything I can do to avoid the periods of lower performance?
> > Ideally I would be processing messages as soon as they are written.
> >
> >
> > On Sun, Apr 21, 2013 at 8:49 AM, Neha Narkhede <[EMAIL PROTECTED]
> > >wrote:
> >
> > > Some of the reasons a consumer is slow are -
> > > 1. Small fetch size
> > > 2. Expensive message processing
> > >
> > > Are you processing the received messages in the consumer ? Have you
> > > tried running console consumer for this topic and see how it performs
> > > ?
> > >
> > > Thanks,
> > > Neha
> > >
> > > On Sun, Apr 21, 2013 at 1:59 AM, Andrew Neilson <[EMAIL PROTECTED]>
> > > wrote:
> > > > I am currently running a deployment with 3 brokers, 3 ZK, 3
> producers,
> > 2
> > > > consumers, and 15 topics. I should first point out that this is my
> > first
> > > > project using Kafka ;). The issue I'm seeing is that the consumers
> are
> > > only
> > > > processing about 15 messages per second from what should be the
> largest
> > > > topic it is consuming (we're sending 200-400 ~300 byte messages per
> > > second
> > > > to this topic). I should note that I'm using a high level ZK consumer

 
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB