key garbage collection

Justin Karneges justin at
Thu Nov 3 14:02:32 EDT 2011

On Thursday, November 03, 2011 02:46:39 AM Erik Søe Sørensen wrote:
> On 03-11-2011 07:39, Justin Karneges wrote:
> > I wonder if anyone else is doing something like this.  I also wonder if
> > there is a flaw in this design.  Since the lack of the cleanup key can
> > indicate a successful commit, I wonder if there might be a problem with
> > eventual consistency whereby some other node sees A and B but not the
> > cleanup key because it hasn't propagated yet, and therefore thinks the
> > keys are valid when in reality they aren't.  Maybe causal consistency
> > ensures this isn't a problem, since the cleanup key is written before A
> > and B?
> If cluster-to-cluster replication is in play, there will be a problem
> here, because the replication order (for full syncs at least) is
> independent of the write order.

You're talking about a W + R <= N case?  I am not sure, but my proposal 
probably only works if causal consistency can be guaranteed (provided it works 
the way I think it does).


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