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From Patrick Hunt <ph...@apache.org>
Subject Re: znode cversion decreasing?
Date Mon, 12 Apr 2010 23:48:24 GMT
Any idea why the connection is flapping so badly? Is this client->server 
connection remote or in colo? (not that than should effect the 
operations of the server...)

Patrick

On 04/12/2010 02:26 PM, Kevin Webb wrote:
> On Mon, 12 Apr 2010 09:27:46 -0700
> Mahadev Konar<mahadev@yahoo-inc.com>  wrote:
>
>> 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 great.
>>
>> Thanks
>> mahadev
>
> Thanks Mahadev and Patrick!
>
> Here are some more details:
>
> I'm using the C client and running three servers on PlanetLab, with
> each server on a different continent.  Most of the time, the cversion
> is increasing as expected.  I'm never deleting the group node, so
> that's not the issue.
>
> Of course, now that I've emailed this list, I haven't seen it happen
> again...
>
> I do have one old log file though:
>
> ZK(10): 1270514949 (Re)Connected to zookeeper server.
> ZK(10): 1270514952 Beginning new view #7.  Unsetting panic...
> GOSSIP(10): 1270514952 Changing view to 7
> ZK(10): 1270515798 Disconnected from zookeeper.  Setting panic...
> ZK(10): 1270515803 (Re)Connected to zookeeper server.
> ZK(10): 1270515806 Beginning new view #7.  Unsetting panic...
> GOSSIP(10): 1270515806 Ignoring delivery request for view 7, current
> view is 7.
> ZK(10): 1270516812 Disconnected from zookeeper.  Setting panic...
> ZK(10): 1270516823 (Re)Connected to zookeeper server.
> ZK(10): 1270516826 Beginning new view #11.  Unsetting panic...
> GOSSIP(10): 1270516826 Changing view to 11
> ZK(10): 1270519191 Disconnected from zookeeper.  Setting panic...
> ZK(10): 1270519195 (Re)Connected to zookeeper server.
> ZK(10): 1270519198 Beginning new view #9.  Unsetting panic...
> GOSSIP(10): 1270519198 Ignoring delivery request for view 9, current
> view is 11.
>
> The large integral number is a Unix seconds-since-epoch timestamp (the
> result of calling time(NULL)).
>
> In this case, the client connected, got group #7, disconnected,
> reconnected, got #7 again, disconnected, reconnected, got #11,
> disconnected, reconnected, and then got #9.
>
> The host string that I pass to zookeeper_init contains only one
> address:port, so it's not an issue of re-connecting to a different
> server and getting old/stale information.
>
>
> If/when it does happen again, I'll be sure to also save the zookeeper
> server logs.
>
> -Kevin

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