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From: Ted Dunning <ted.dunning@gmail.com>
Date: Thu, 5 May 2011 22:29:39 -0700
Message-ID: <BANLkTik1Q1BsPzXY=2xozjp4e0US0bQ=QA@mail.gmail.com>
Subject: Re: What is the order of read watch and write completion?
To: user@zookeeper.apache.org
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This example seems a bit confused.

If there is a watch on /b and /a is changed, then the watch on /b will not
be triggered.

Can you rephrase your question?

On Thu, May 5, 2011 at 8:47 PM, =E9=82=A2=E8=BF=AA=E4=BE=83 <xingdk.apex@gm=
ail.com> wrote:

> Hi, All,
>
> I'm not sure whether the response (from the client perspective, the
> completion callback or the return of a sync call) to a success write
> (create, delete, etc) is also queued in the right place among read
> completion and read watch.
>
> In detail, for example the current view is:
> /a: oldA
> /b: oldB
>
> And from the perspective of the zk server, it handles the following two
> change in the shown order:
> a) /a changes to newA
> b) /b changes to newB
>
> I understand, if Tom sets the read watch previously, before reading out t=
he
> new content of "/b", Tom will get watch notification of "/a".
> My question is if Tom is not reading, but writing. It is Tom that changes
> the content of /b. Then is there guarantee that the watch notification of
> "/a" will preceed the completion callback (if Tom asetData()) and the
> return
> of setData?
>
> In other words, will the server queue the response to the client's write
> request only after previous writes are locally played and triggered watch=
es
> are handled and queued into TCP sending tunnel?
> Or say, is a success response to a write request a part of a consistent
> view
> for a client?
>
> XING Dikan
>

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