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From "Kevin Burton" <bur...@spinn3r.com>
Subject Persistent watches........
Date Sun, 04 Jan 2009 04:05:32 GMT
> Because watches are one time triggers and there is latency between getting
> event and sending a new request to get a watch you cannot reliably see
> change that happens to a node in ZooKeeper. Be prepared to handle the case
> the znode changes multiple times between getting the event and setting the
> again. (You may not care, but at least realize it may happen.)

This seems the opposite of what would be desirable in an ideal client.

So if I'm only using watches, and a file is changed with values 1,2,3,4
rapidly, I may lose and never see value 4?  Or I'll just not see 2,3?

In one situation I'm worried about have a distributed process I'm trying to
start, stop. I wouldn't want them to drop the second stop.

How hard would it be to have every mutate event (delete, write, acl change,
etc) be an event which is persistent and the client sees every change?


Founder/CEO Spinn3r.com
Location: San Francisco, CA
AIM/YIM: sfburtonator
Skype: burtonator
Work: http://spinn3r.com

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