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From Edward Ribeiro <edward.ribe...@gmail.com>
Subject Re: EPEHMERAL_SEQUENCIAL and EPHEMERAL_SEQUENTIAL constants
Date Fri, 20 Jun 2014 13:42:30 GMT
Hi Lahiru,

You mean EPHEMERAL and EPHEMERAL_SEQUENTIAL, right?

A znode is created by a client logged on a session. Both EPHEMERAL and
EPHEMERAL_SEQUENTIAL znodes are deleted once the session -- where the znode
was created --  expires (that is, the user disconnects). The difference
between the two types of ephemeral node is that EPHEMERAL_SEQUENTIAL allows
you to create an atomic and sequentially increasing number suffixes.

For example, if three clients are trying to create child
ephemeral_sequential znodes of a '/leader' parent znode at the same time
they will be generated as follows (for example):

/leader/serv_000000001
/leader/serv_000000002
/leader/serv_000000003

the number suffix was automatically appended by ZK such that no two clients
will generate the same znode (serv_00000001, for example). If the client
which created znode 'serv_00000002' disconnects then ZK automatically
deletes that znode.

Got it?

Edward





On Thu, Jun 19, 2014 at 2:53 PM, Lahiru Gunathilake <glahiru@gmail.com>
wrote:

> When creating a node we have to parse the constants and there are four.
> PERSISTENT, PERSISTENT_SEQUENTIAL, EPHEMERAL, EPHEMERAL_SEQUENTIAL
>
> I do not really get the description of two constants EPEHMERAL_SEQUENCIAL
> and EPHEMERAL_SEQUENTIAL. In API docs it says like below.
>
> The znode will be deleted upon the client's disconnect, and its name will
> be appended with a monotonically increasing number.
>
> Can someone please describe me what this is about.
>
> Regards
> Lahiru
>
> --
> System Analyst Programmer
> PTI Lab
> Indiana University
>

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