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From Mahadev Konar <maha...@hortonworks.com>
Subject Re: zk keeps disconnecting and reconnecting
Date Mon, 29 Aug 2011 18:10:11 GMT
Camille,
 Do you think we should put the fix in 3.3.4? I think 3.4 might take a while to stabilize,
so 3.3.4 would be a good release to get this in.

Thoughts?

mahadev

On Aug 29, 2011, at 10:50 AM, Fournier, Camille F. wrote:

> Well, it causes the problem you are seeing. If you set any watchers with a chroot and
then your client gets disconnected with these watches outstanding, when you reconnect you
will try to reset them and they are probably on paths that don't exist (if you are creating
everything under path /kafka-tracking). So you get a notification about the watches immediately
after resetting them, which causes the string out of bounds exception. 
> 
> The only fix is to disable auto watch reset, and then have your own client reset watches
when it gets a reconnected event. I suspect it would be easier for you to take a shot at fixing
the bug than to rewrite your client to handle this. Thomas provided a patch with tests that
presumably show the error, so all you need is a fix to make them pass.
> 
> 
> C
> 
> -----Original Message-----
> From: Jun Rao [mailto:junrao@gmail.com] 
> Sent: Monday, August 29, 2011 12:39 PM
> To: user@zookeeper.apache.org; thomas@koch.ro
> Subject: Re: zk keeps disconnecting and reconnecting
> 
> What's the impact of ZOOKEEPER-961? If it shows up, does that mean the
> client won't get any watcher events afterwards? If so, this sounds like a
> blocker for 3.4 release to me. What's the temporary solution for 3.3.3?
> 
> Also, for the very first time that the ZK client gets disconnected, I saw
> the following entry in the log. It seems that the client can't ping the
> server for 4 seconds. The ZK server was up at that time and the load was
> minimal. What could cause the time out? Client GC pauses?
> 
> 2011/08/26 10:58:22.306 INFO [ClientCnxn]
> [main-SendThread(esv4-app27.stg:12913)] [kafka] Client session timed out,
> have not heard from server in 4001ms for sessionid 0x131f
> ddd84bc0006, closing socket connection and attempting reconnect
> 
> Thanks,
> 
> Jun
> 
> On Mon, Aug 29, 2011 at 7:54 AM, Thomas Koch <thomas@koch.ro> wrote:
> 
>> Fournier, Camille F.:
>>> Did anyone ever check resetting watches at client reconnect on a client
>>> with a chroot? Looking at the code, we store the watches associated with
>>> the non-chroot path, but they are set by the original request prepending
>>> chroot to the request. However, it looks like the SetWatches request on
>>> reconnect just calls get on the various watch lists from ZooKeeper, which
>>> don't have the prepended chroot.
>>> 
>>> I haven't written a test but I would bet dollars to donuts this is the
>>> problem.
>>> 
>>> C
>> seems to be this:
>> ZOOKEEPER-961, ZOOKEEPER-1091
>> 
>> Regards,
>> 
>> Thomas Koch, http://www.koch.ro
>> 


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