Did you try this on an otherwise empty topic?
Yes and it blocks until --messages are read. But again, my interpretation
of that config has been - "read exactly --messages # of messages, not less
not more".
Thanks,
Neha
On Mon, Feb 10, 2014 at 9:31 AM, Jay Kreps <jay.kr...@gmail.com> wrote:
> Hmm, I could be wrong... Did you try this on an otherwise empty topic? Try
> this:
> 1. Produce 100GB of messages
> 2. Run consumer performance test with --messages 1
> 3. Go get some coffee
> 4. Observe performance tests results with a time taken to consume 100GB of
> messages but only recording a single message consumed
>
> :-)
>
> Here is what I mean:
> scala> val l = List(1,2,3,4,5,6,7,8,9,10)
> scala> val iter = l.iterator
> scala> var count = 0
> scala> for(i <- iter if count < 5) {
> scala> iter.next
> java.util.NoSuchElementException: next on empty iterator
> ...
>
> This is the exact equivalent of
> val l = List(1,2,3,4,5,6,7,8,9,10)
> val iter = l.iterator
> var count = 0
> while(iter.hasNext) {
> if(iter.next < 5)
> count += 1
> }
>
> -Jay
>
>
> On Sun, Feb 9, 2014 at 9:43 PM, Neha Narkhede <neha.narkh...@gmail.com
> >wrote:
>
> > I ran ConsumerPerformance with different number of messages config for a
> > topic that has 100s of messages in the log. It did not hang in any of
> these
> > tests -
> >
> > nnarkhed-mn1:kafka-git-idea nnarkhed$ ./bin/kafka-run-class.sh
> > kafka.perf.ConsumerPerformance --zookeeper localhost:2181 --topic test
> > *--messages
> > 10* --threads 1
> > start.time, end.time, fetch.size, data.consumed.in.MB, MB.sec,
> > data.consumed.in.nMsg, nMsg.sec
> > 1 messages read
> > 2 messages read
> > 3 messages read
> > 4 messages read
> > 5 messages read
> > 6 messages read
> > 7 messages read
> > 8 messages read
> > 9 messages read
> > 10 messages read
> > *2014-02-09 21:39:47:385, 2014-02-09 21:39:52:641, 1048576, 0.0015,
> 0.0060,
> > 10, 39.0625* (test ends with this)
> > nnarkhed-mn1:kafka-git-idea nnarkhed$ ./bin/kafka-run-class.sh
> > kafka.perf.ConsumerPerformance --zookeeper localhost:2181 --topic test
> > *--messages
> > 2* --threads 1
> > 1 messages read
> > 2 messages read
> > *2014-02-09 21:39:59:853, 2014-02-09 21:40:05:100, 1048576, 0.0003,
> 0.0011,
> > 2, 8.0972* (test ends with this)
> >
> > The way I read the --messages config is "read exactly --messages # of
> > messages, not less not more". If the topic has less than --messages
> > records, it will hang until it gets more data, else it exits properly.
> > Seems like expected behavior.
> >
> > Thanks,
> > Neha
> >
> >
> >
> > On Sat, Feb 8, 2014 at 2:11 PM, Jay Kreps <jay.kr...@gmail.com> wrote:
> >
> > > It loops on
> > > for (messageAndMetadata <- stream if messagesRead <
> > config.numMessages) {
> > > // count message
> > > }
> > >
> > > That means it loops over *all* messages in the stream (eventually
> > blocking
> > > when all messages are exhausted) but only counts the first N as
> > determined
> > > by the config.
> > >
> > > As a result this command seems to always hang forever. Seems like
> someone
> > > "improved" this without ever trying to run it :-(
> > >
> > > -Jay
> > >
> >
>
