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From Alexander Shraer <shra...@gmail.com>
Subject Re: ZooKeeper transaction properties (partial read)
Date Wed, 03 Feb 2016 03:18:29 GMT
Hi,

I think this situation shouldn't happen - the result of step 3 implies that
the multi happened, so 4 should see it (multi should be atomic). Could you
please open a high priority bug for this ?

Thanks,
Alex

On Mon, Feb 1, 2016 at 2:40 PM, Whitney Sorenson <wsorenson@hubspot.com>
wrote:

> 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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