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From Patrick Hunt <ph...@apache.org>
Subject Re: Watcher guarantees
Date Fri, 13 Feb 2009 18:17:47 GMT
Tom White wrote:
> If client sets a watcher on a znode by doing a getData operation is it
> guaranteed to get the next change after the value it read, or can a
> change be missed?

> In other words if the value it read had zxid z1 and the next update of
> the znode has zxid z2, will the watcher always get the event for the
> change z2?

Yes, that is a strong guarantee. See the following:
http://hadoop.apache.org/zookeeper/docs/r3.0.1/zookeeperProgrammers.html#sc_WatchGuarantees

Patrick

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