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Kafka >> mail # user >> Topic creation on restart


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Re: Topic creation on restart
Ok,

After adding a delay before enabling a freshly started broker in the
metadata vip that clients use, it seems to have drastically reduced the
number of these topic creation requests.  However, not all of them.

I still see (only some times) a handful of "Topic creation" log messages,
that happen on a freshly started broker, during the time kafka has started,
but before the broker has been enabled in the metadata VIP.  Is there an
explanation for this?

Thanks!

Jason
On Fri, Nov 1, 2013 at 4:45 PM, Neha Narkhede <[EMAIL PROTECTED]>wrote:

> The mbeans are explained here -
> http://kafka.apache.org/documentation.html#monitoring. Look for
> *QueueTimeMs
>
> Thanks,
> Neha
>
>
> On Fri, Nov 1, 2013 at 12:14 PM, Jason Rosenberg <[EMAIL PROTECTED]> wrote:
>
> > Neha,
> >
> > This cluster has on the order of 750 topics.
> >
> > It looks like if I add a 20 second delay before placing a broker into the
> > vip for metadata requests, it never seems to have this issue.  So I'm not
> > sure about the 104 seconds number, other than that was how long the flood
> > of "Topic creation" log messages went on for (over 500 of these).
> >
> > Which metric should I look at for 'high queue time'?
> >
> > Jason
> >
> >
> > On Fri, Nov 1, 2013 at 5:54 AM, Neha Narkhede <[EMAIL PROTECTED]
> > >wrote:
> >
> > > It is proportional to the number of topics but still seems too long.
> Did
> > > the broker have high queue time on all requests? Also how many topics
> > > existed on this cluster?
> > >
> > > Thanks,
> > > Neha
> > > On Oct 31, 2013 10:56 PM, "Jason Rosenberg" <[EMAIL PROTECTED]> wrote:
> > >
> > > > In this case, it appears to have gone on for 104 seconds.  Should it
> > take
> > > > that long?  It doesn't seem to always take this long.  I guess one of
> > the
> > > > drawbacks of having a large number of topics (brings out the edge
> > cases).
> > > >
> > > > Filed: https://issues.apache.org/jira/browse/KAFKA-1111
> > > >
> > > >
> > > > On Fri, Nov 1, 2013 at 1:17 AM, Neha Narkhede <
> [EMAIL PROTECTED]
> > > > >wrote:
> > > >
> > > > > >> Would it be possible for the broker to make sure all metadata is
> > > > > propagated, before completing the startup sequence, and taking on
> > > > metadata
> > > > > requests?
> > > > >
> > > > > Yes, that is the flaw I mentioned before. We need to fix it.
> > > > >
> > > > >
> > > > > On Thu, Oct 31, 2013 at 9:56 PM, Jason Rosenberg <[EMAIL PROTECTED]
> >
> > > > wrote:
> > > > >
> > > > > > Ok,
> > > > > >
> > > > > > So, I can safely ignore these, it sounds like.  I don't see any
> > > > > > corresponding logging around it subsequently not succeeding to
> > > actually
> > > > > > create the topic in zk.
> > > > > >
> > > > > > Would it be possible for the broker to make sure all metadata is
> > > > > > propagated, before completing the startup sequence, and taking on
> > > > > metadata
> > > > > > requests?
> > > > > >
> > > > > > If I were to not place the newly started broker back into the vip
> > > for a
> > > > > > delay period after the kafka broker has started, would that solve
> > > this
> > > > > > issue?
> > > > > >
> > > > > > Jason
> > > > > >
> > > > > >
> > > > > > On Fri, Nov 1, 2013 at 12:39 AM, Jun Rao <[EMAIL PROTECTED]>
> wrote:
> > > > > >
> > > > > > > This is probably because some metadata requests were issued to
> a
> > > > newly
> > > > > > > started broker before the controller has propagated the
> metadata.
> > > > Since
> > > > > > the
> > > > > > > broker doesn't have the metadata in the cache, it thinks the
> > topic
> > > > > > doesn't
> > > > > > > exist and tries to create the topic. The creation will fail
> > though
> > > > > since
> > > > > > > it's already registered in ZK. These INFO logging should be
> > > transient
> > > > > > > though.
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > >
> > > > > > > On Thu, Oct 31, 2013 at 8:41 PM, Jason Rosenberg <
> > [EMAIL PROTECTED]
> > > >
> > > > > > wrote:
> > > > > > >

 
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