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Posted to user@curator.apache.org by Benjamin Jaton <bj...@radiantlogic.com> on 2013/07/18 00:35:02 UTC
Watching children changes
Hello,
I would like to be notified of a change on any of the children of a znode
(could be a lot of them).
AFAIK to achieve this we need to set a watcher on each child and then also
watch the parent to be aware of children addition/deletion and add/remove
watchers accordingly. Is that correct?
What is the performance impact of having for example thousands of watchers?
Thanks,
Ben
Re: Watching children changes
Posted by Jordan Zimmerman <jo...@jordanzimmerman.com>.
BTW - You can use PathChildrenCache for this purpose: http://curator.incubator.apache.org/curator-recipes/path-cache.html
On Jul 17, 2013, at 3:46 PM, Benjamin Jaton <bj...@radiantlogic.com> wrote:
> Shoot, yes, I'll move my question to the ZK list.
>
>
> On Wed, Jul 17, 2013 at 3:40 PM, Jordan Zimmerman <jo...@jordanzimmerman.com> wrote:
> > What is the performance impact of having for example thousands of watchers?
>
> It's an important consideration. This question might be better for the ZK list, BTW. I know that Facebook is working on a general watcher capability - i.e. notify me of everything. But, I don't know what its status is.
>
> -JZ
>
> On Jul 17, 2013, at 3:35 PM, Benjamin Jaton <bj...@radiantlogic.com> wrote:
>
> > Hello,
> >
> > I would like to be notified of a change on any of the children of a znode (could be a lot of them).
> >
> > AFAIK to achieve this we need to set a watcher on each child and then also watch the parent to be aware of children addition/deletion and add/remove watchers accordingly. Is that correct?
> >
> > What is the performance impact of having for example thousands of watchers?
> >
> > Thanks,
> > Ben
> >
>
>
Re: Watching children changes
Posted by Benjamin Jaton <bj...@radiantlogic.com>.
Shoot, yes, I'll move my question to the ZK list.
On Wed, Jul 17, 2013 at 3:40 PM, Jordan Zimmerman <
jordan@jordanzimmerman.com> wrote:
> > What is the performance impact of having for example thousands of
> watchers?
>
> It's an important consideration. This question might be better for the ZK
> list, BTW. I know that Facebook is working on a general watcher capability
> - i.e. notify me of everything. But, I don't know what its status is.
>
> -JZ
>
> On Jul 17, 2013, at 3:35 PM, Benjamin Jaton <bj...@radiantlogic.com>
> wrote:
>
> > Hello,
> >
> > I would like to be notified of a change on any of the children of a
> znode (could be a lot of them).
> >
> > AFAIK to achieve this we need to set a watcher on each child and then
> also watch the parent to be aware of children addition/deletion and
> add/remove watchers accordingly. Is that correct?
> >
> > What is the performance impact of having for example thousands of
> watchers?
> >
> > Thanks,
> > Ben
> >
>
>
Re: Watching children changes
Posted by Jordan Zimmerman <jo...@jordanzimmerman.com>.
> What is the performance impact of having for example thousands of watchers?
It's an important consideration. This question might be better for the ZK list, BTW. I know that Facebook is working on a general watcher capability - i.e. notify me of everything. But, I don't know what its status is.
-JZ
On Jul 17, 2013, at 3:35 PM, Benjamin Jaton <bj...@radiantlogic.com> wrote:
> Hello,
>
> I would like to be notified of a change on any of the children of a znode (could be a lot of them).
>
> AFAIK to achieve this we need to set a watcher on each child and then also watch the parent to be aware of children addition/deletion and add/remove watchers accordingly. Is that correct?
>
> What is the performance impact of having for example thousands of watchers?
>
> Thanks,
> Ben
>