You are viewing a plain text version of this content. The canonical link for it is here.
Posted to user@cassandra.apache.org by Ran Tavory <ra...@gmail.com> on 2009/12/06 21:41:58 UTC
vector clocks?
As a Cassandra newbe, after having read the Dynamo paper, I was wondering -
how does Cassandra use timestamps?
- Does it use them internally to resolve conflicts?
- Does it expose vector clocks to clients when internal conflict resolution
fails?
Thanks
Re: vector clocks?
Posted by Jonathan Ellis <jb...@gmail.com>.
On Mon, Dec 7, 2009 at 8:45 AM, Ran Tavory <ra...@gmail.com> wrote:
> So, currently, is Cassandra using the client provided timestamps for
> conflict resolution?
yes
> Do clients have insight to conflicts Cassandra cannot resolve
no, and there's no such thing as "conflicts Cassandra cannot resolve," either
> What's the semantic of "eventual consistency" in Cassandra's case then?
eventually (immediately, if R + W > N), every read will return the
most recent write
Re: vector clocks?
Posted by Ran Tavory <ra...@gmail.com>.
So, currently, is Cassandra using the client provided timestamps for
conflict resolution? (Or something else?)
Do clients have insight to conflicts Cassandra cannot resolve (assuming it
tries to resolve them)?
What's the semantic of "eventual consistency" in Cassandra's case then?
On Mon, Dec 7, 2009 at 12:34 AM, Kelvin Kakugawa <ka...@gmail.com> wrote:
> Cassandra, right now, doesn't use vector clocks internally. However,
> an implementation is being worked on, here:
> https://issues.apache.org/jira/browse/CASSANDRA-580
>
> -Kelvin
>
> On Sun, Dec 6, 2009 at 10:41 AM, Ran Tavory <ra...@gmail.com> wrote:
> > As a Cassandra newbe, after having read the Dynamo paper, I was wondering
> -
> > how does Cassandra use timestamps?
> > - Does it use them internally to resolve conflicts?
> > - Does it expose vector clocks to clients when internal conflict
> resolution
> > fails?
> > Thanks
> >
>
Re: vector clocks?
Posted by Kelvin Kakugawa <ka...@gmail.com>.
Cassandra, right now, doesn't use vector clocks internally. However,
an implementation is being worked on, here:
https://issues.apache.org/jira/browse/CASSANDRA-580
-Kelvin
On Sun, Dec 6, 2009 at 10:41 AM, Ran Tavory <ra...@gmail.com> wrote:
> As a Cassandra newbe, after having read the Dynamo paper, I was wondering -
> how does Cassandra use timestamps?
> - Does it use them internally to resolve conflicts?
> - Does it expose vector clocks to clients when internal conflict resolution
> fails?
> Thanks
>