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From Scott Blum <dragonsi...@gmail.com>
Subject Re: Determining ZNode change for the cache recipes
Date Sun, 12 Mar 2017 21:14:02 GMT
Oh, this is related to CURATOR-391
https://github.com/apache/curator/pull/202

You wrote:

> Using only Stat version to note node change (for UPDATE event) is not
> enough. In a split brain if a node delete plus a recreate is missed, the
> Stat version can appear to be the same.


I never considered this corner case!  So yeah, I agree that mxzid would be
more reliable.


On Sun, Mar 12, 2017 at 5:09 PM, Scott Blum <dragonsinth@gmail.com> wrote:

> I think "version" and "mzxid" should be equally reliable for determining
> that the contents changed.  Whenever a change happens the version gets
> incremented while the mzxid gets set to the associated zk transaction id.
> So I don't see a problem with ifVersion == data.getStat().getVersion() but
> I haven't looked through all the PathChildrenCache code in a while, was
> there something else you were referring to going on in there?
>
> On Sun, Mar 12, 2017 at 1:23 PM, Jordan Zimmerman <
> jordan@jordanzimmerman.com> wrote:
>
>> I'm working on CURATOR-391 and notice that TreeCache uses Mzxid to
>> determine if a ZNode has changed. PathChildrenCache uses a less reliable
>> method. I _think_ that Mzxid is enough. Does everyone else agree?
>>
>> -Jordan
>
>
>

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