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From Mahadev Konar <maha...@yahoo-inc.com>
Subject Re: znode cversion decreasing?
Date Mon, 12 Apr 2010 16:27:46 GMT
HI Kevin,

 The cversion should be monotonically increasing for the the znode. It would
be a bug if its not. Can you please elaborate in which cases you are seeing
the cversion decreasing? If you can reproduce with an example that would be


On 4/11/10 3:53 PM, "Kevin Webb" <kcwebb@cs.ucsd.edu> wrote:

> I'm using Zookeeper (3.2.2) for  a simple group membership service in
> the manner that is typically described[1,2]:
> I create a znode for the group, and each present group member adds an
> ephemeral node under the group node.  I'm using the cversion of the
> group node as a "group number". I expected this value to be
> monotonically increasing, but I'm seeing instances where this isn't
> the case.  According to the programmer's guide, changes to a node will
> cause the appropriate version number to increase, but it says nothing
> about decreasing.
> Am I misunderstanding something about the way node version numbers
> work?  Is there a better/recommended way to implement a monotonically
> increasing group number?
> Thanks!
> Kevin
> [1] http://hadoop.apache.org/zookeeper/docs/r3.2.2/recipes.html
> [2] http://eng.kaching.com/2010/01/actually-implementing-group-management.html

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