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From "Norbert Kalmar (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (ZOOKEEPER-834) Allow ephemeral znodes to have children created only by the owner session.
Date Wed, 20 Mar 2019 15:29:00 GMT

     [ https://issues.apache.org/jira/browse/ZOOKEEPER-834?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Norbert Kalmar resolved ZOOKEEPER-834.
--------------------------------------
       Resolution: Duplicate
    Fix Version/s:     (was: 3.6.0)

> Allow ephemeral znodes to have children created only by the owner session. 
> ---------------------------------------------------------------------------
>
>                 Key: ZOOKEEPER-834
>                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-834
>             Project: ZooKeeper
>          Issue Type: New Feature
>          Components: c client, java client, server
>            Reporter: Andrei Savu
>            Assignee: Rakesh R
>            Priority: Major
>              Labels: container_znode_type
>         Attachments: ZOOKEEPER-834.1.patch, ZOOKEEPER-834.2.patch, ZOOKEEPER-834.patch,
ZOOKEEPER-834.patch
>
>
> Ephemeral znodes are automatically removed when the client session is closed or expires
and this behavior makes them very useful when you want to publish status information from
active / connected clients. 
> But there is a catch. Right now ephemerals can't have children znodes and because of
that clients need to serialize status information as byte strings. This serialization renders
that information almost invisible to generic zookeeper clients and hard / inefficient to update.

> Most of the time the status information can be expressed as a bunch of (key, value) pairs
and we could easily store that using child znodes. Any ZooKeeper client can read that info
without the need to reverse the serialization process and we can also easily update it. 
> I suggest that the server should allow the ephemeral znodes to have children znodes.
Each child should also be an ephemeral znode owned by the same session - parent ephemeralOwner
session.
> Mail Archive: 
> http://www.mail-archive.com/zookeeper-dev@hadoop.apache.org/msg09819.html
> Another discussion about the same topic:
> http://www.mail-archive.com/zookeeper-dev@hadoop.apache.org/msg08165.html



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