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Date: Wed, 1 Jun 2011 15:14:21 -0700
Message-ID: <BANLkTinPqNCnK7c+jwwfs_RdcH-1enxCGg@mail.gmail.com>
Subject: Re: lost ZK events across datacenters
From: Jun Rao <junrao@gmail.com>
To: user@zookeeper.apache.org
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All my clients were on different machines. 2 of them got the watcher fired
about the same time. The third one never got the watcher triggered.

Thanks,

Jun

On Wed, Jun 1, 2011 at 2:18 PM, Fournier, Camille F. [Tech] <
Camille.Fournier@gs.com> wrote:

> All clients are in different processes?
> I've used zkclient and haven't seen any problems, but I haven't hammered it
> too hard yet. I took a long look at the code and didn't see any errors but
> there could always be something very subtle.
>
> -----Original Message-----
> From: Jun Rao [mailto:junrao@gmail.com]
> Sent: Wednesday, June 01, 2011 4:09 PM
> To: user@zookeeper.apache.org
> Subject: Re: lost ZK events across datacenters
>
> I am using the zkclient package (
> https://github.com/sgroschupf/zkclient.git).
> The watcher code seems reasonable. Basically, each watcher event is first
> added to a queue. A separate event thread dequeues each event and reads the
> children of a path (which re-registers the watcher) and invokes the
> registered listener.
>
> Anybody knows any issues in zkclient?
>
> Thanks,
>
> Jun
>
> On Wed, Jun 1, 2011 at 12:04 PM, Ted Dunning <ted.dunning@gmail.com>
> wrote:
>
> > This is most commonly due, in my own history of programming errors, to
> > writing code that has a race window in it.  It is conceivable that cross
> > data-center operation would make such a race more of a problem.
> >
> > Can you say a bit about your code?  Did you make sure to use standard
> > idioms
> > as opposed to setting the watch in a different call from reading the
> data?
> >
> > On Wed, Jun 1, 2011 at 11:40 AM, Jun Rao <junrao@gmail.com> wrote:
> >
> > > Hi,
> > >
> > > I have a setup where multiple ZK clients are sitting in a different
> > > datacenter from the ZK server. All clients registered the same child
> > > watcher
> > > on a path. However, when the children of the path changed, the watcher
> on
> > 1
> > > of the clients didn't fire. This seems to have happened a couple of
> times
> > > to
> > > me. I am using ZK 3.3.3. Has anyone used ZK in a cross datacenter setup
> > and
> > > seen problems like that before?
> > >
> > > Thanks,
> > >
> > > Jun
> > >
> >
>

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