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From Camille Fournier <cami...@apache.org>
Subject Re: Question regarding ZK behaviour during leader reelection
Date Mon, 16 Jan 2012 18:39:08 GMT
Yes your clients always need to handle state changes gracefully, and
absolutely, disconnect will happen when there is a change in leadership.


On Mon, Jan 16, 2012 at 1:28 PM, yuliya Feldman <yufeldman@yahoo.com> wrote:

> Does not look like this question made to a forum.
> Resending it in hope that somebody from ZK developers will answer.
> Thanks.
> ________________________________
>  From: yuliya Feldman <yufeldman@yahoo.com>
> To: "user@zookeeper.apache.org" <user@zookeeper.apache.org>
> Sent: Thursday, January 5, 2012 2:30 PM
> Subject: Question regarding ZK behaviour during leader reelection
> Hello here,
> I have a question regarding ZK clients behaviour during ZK Leader
> reelection.
> We have a situation where server where ZK Leader was running run low on
> memory and essentially ZK was "frozen" for quite a bit of time.
> Meanwhile other 2 ZK servers did reelections among them and new Leader was
> chosen.
> Now on ZK client nodes (not taking "bad" node into consideration) got
> Disconnect and Closely after Connect events, because as far as I understand
> no leader was available for about 500 ms. (during reelection).
> The question really is - as it is very likely that it will be some time
> during ZK leader election when none of the ZK servers will be available ZK
> clients are very likely to "feel" that something happened on the ZK Server
> (Quorum side).
> Which means that ANY application that relies on Zookeeper has to at least
> handle Disconnect event gracefully.
> Are my assumptions correct?
> Thanks.

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