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From Edward Ribeiro <edward.ribe...@gmail.com>
Subject Re: EPEHMERAL_SEQUENCIAL and EPHEMERAL_SEQUENTIAL constants
Date Mon, 23 Jun 2014 00:32:02 GMT
Hi,

Rakesh already answered your question, but let me just reinforce some
points:


On Fri, Jun 20, 2014 at 10:50 AM, Lahiru Gunathilake <glahiru@gmail.com>
wrote:

> ​
> so the usecase is when two clients try to create same nodes with same name
> ​​
> z
> ​​
> k
> ​​
> ​​
> ch
> ​​
> a
> ​​
> n
> ​​
> g
> ​​
> e
> ​​
> ​​
> t
> ​​
> h
> ​​
> e
> ​​
> ​​
> n
> ​​
> a
> ​​
> m
> ​​
> i
> ​​
> n
> ​​
> g
> ​​
> ​​
> ?
> ​​
> ​​
>

Nope. When creating a sequential znode you inform a prefix (e.g., "serv_")
and ZK provides the number part. The final name will be your prefix + the
number (i.e., serv_0000007). The big plus is that the number part is
atomically and sequentially provided so no more than one client will create
the znode with this full path name.

​

> I
> ​​
> ​​
> ​​
> ​​
> f my system is well defined and no ra
> ​​
> ndom node
> ​​
> creation I do not need this feature ?
> ​
>

This feature is used for leader election among ZK clients, for example.
Other cases can for sure make use of sequential znodes.
​

> ​​
>
> In this case can I just get th
> ​​
> e node with /leader/serv or should I get with
> /leader/serv_000000001
> ​
>

Later option, as Rakesh wrote.​
​

> ​
>
>
> Anyways for my application I do not need this because I do not have a
> scenario where naming is nondeterministic between zk clients.
> ​
>

I would not say that it is "non deterministic". More like, you have an
atomically increasing numbered znode suffix name. ;)

Regards,
Edward​

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