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From Patrick Hunt <ph...@apache.org>
Subject Re: zoo_set() version question
Date Fri, 12 Dec 2008 20:39:50 GMT
Mahadev Konar wrote:
> And you have a success, then the version of the node that denots your
> successful zoo_set() above is
>  = Version +1 

Mahadev, that's the current implementation, but I wasn't aware we were 
exposing that detail as something users should rely on. Is it documented 
anywhere in the docs? If this is "user visible" we should document it, I 
thought we weren't exposing this for a reason...

> mahadev
> On 12/12/08 11:36 AM, "Avery Ching" <aching@yahoo-inc.com> wrote:
>> Patrick,
>> Thanks for responding.
>> I agree that I can use zoo_exists and zoo_get to get the version of the
>> znode as it exists currently.
>> The problem I am trying to solve is that getting the version from struct
>> Stat in either zoo_exists or zoo_get may not be the same version that my
>> last successful zoo_set used.  I would like to get the version that denotes
>> my last successful zoo_set() operation to a particular znode.
>> I understand that the data and version to the znode may change immediately
>> one or multiple times after my zoo_set() and this is fine, but I would still
>> like to know the znode's versions of the data I set.
>> Avery
>> On 12/12/08 11:11 AM, "Patrick Hunt" <phunt@apache.org> wrote:
>>> Avery Ching wrote:
>>>> If zoo_set() completes successfully with version != -1, can we assume that
>>>> version -> version + 1 for this znode?  If not, is there a way for the
>>>> to get the version of the successfully completed zoo_set() operation?
>>> You shouldn't rely on this, it may work, but it's not part of the
>>> contract. Also, nothing says that some other client won't change the
>>> node immediately after you change it.
>>> You can access the version using zoo_exists or zoo_get - specifically
>>> the "struct Stat stat" argument of either of those methods contains a
>>> "version" member.
>>> Patrick

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