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From "FPJ" <fpjunque...@yahoo.com>
Subject RE: Rolling config change considered harmful?
Date Fri, 14 Jun 2013 19:27:52 GMT
In the case I described, the txn is not reflected in the zookeeper state.
Say T is a create txn. Once C is elected, it determines the initial history
of txns for the new epoch that is starting and this initial history is not
going to include T. 

In the example below, I was ignoring the client that triggered T, but since
it has been acked by a quorum, the client might as well have received the
confirmation of the operation and think that the znode has been created.


> -----Original Message-----
> From: Jordan Zimmerman [mailto:jordan@jordanzimmerman.com]
> Sent: 14 June 2013 20:16
> To: user@zookeeper.apache.org
> Subject: Re: Rolling config change considered harmful?
> Yes - save that I'm not sure what happens with a client when a transaction
> lost. What is the error to the client? Or are you referring to internal
> transactions as part of the leader election?
> -JZ
> On Jun 14, 2013, at 12:07 PM, "FPJ" <fpjunqueira@yahoo.com> wrote:
> > Not sure if this helps but here is an example:
> >
> > - Txn T is acknowledged by A and B (ensemble is {A, B, C})
> > - Ensemble changes to {B, C, D}
> > - C and D form a quorum and elect C because it has the highest zxid.
> >
> > C won't have T, so the txn gets lost.
> >
> > Does it make sense?
> >
> > -Flavio

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