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From Whitney Sorenson <wsoren...@hubspot.com>
Subject Re: ZooKeeper transaction properties (partial read)
Date Mon, 01 Feb 2016 22:40:36 GMT
1. Starting state : { /foo = <does not exist>, /bar = <does not exist> }
2. In a multi, write: { /foo = A, /bar = B}
3. Read /foo as A
4. Read /bar as <does not exist>

#3 and #4 are issued 100% sequentially.

It is not known at what point during #2, #3 starts.

- Whitney


On Mon, Feb 1, 2016 at 5:08 PM, Jared Cantwell <jared.cantwell@gmail.com>
wrote:

> Am I understanding you correctly that you are observing the following?
>
>    1. Starting state {/foo = A , /bar = B}
>    2. In a multi, write {/foo->A', /bar = B'}
>    3. Read /foo as A'
>    4. Read /bar as B
>
> #3 & #4 start after #2 completes entirely, right?  And #3 & #4 are issued
> 100% sequentially?
>
> ~Jared
>
> On Mon, Feb 1, 2016 at 2:54 PM, Alexander Shraer <shralex@gmail.com>
> wrote:
>
> > Reading the 965 JIRA what you're describing sounds like a bug.
> >
> > Alex
> >
> > On Mon, Feb 1, 2016 at 10:41 AM, Whitney Sorenson <wsorenson@hubspot.com
> >
> > wrote:
> >
> > > Hi,
> > >
> > > In searching through the ZK documentation, this list,
> > > https://issues.apache.org/jira/browse/ZOOKEEPER-965, and curator
> > > documentation (which we're using to talk to ZK) I can't find anything
> > > definitive explaining the guarantees around using transactions.
> > >
> > > I am now beginning to wonder if I wrongly assumed that partial reads
> were
> > > not possible during transactions, because I have now observed this
> > behavior
> > > twice.
> > >
> > > I'd just like to confirm that this is the expected behavior:
> > >
> > > ZK 3.4.6
> > > Curator 2.8.0
> > >
> > > I write 2 nodes in a transaction, however, I am able to see one of the
> > > nodes without seeing the other in 2 subsequent reads.
> > >
> > > Eventually, I am able to see both nodes. When I am talking about seeing
> > the
> > > nodes I am talking about reads from the same client which issued the
> > > transaction talking to the same ZK server.
> > >
> > > - Whitney
> > >
> >
>

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