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From Michael Greene <michael.gre...@gmail.com>
Subject Re: triggers in cassandra
Date Fri, 25 Sep 2009 17:35:26 GMT
Additionally, Cassandra client connections and the Thrift API are not
designed to be stateful.  For what it's worth, Apache Zookeeper offers such
change notifications, but has a very different architecture.
Michael

On Fri, Sep 25, 2009 at 12:25 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> That's a bad fit for Cassandra, since the machine any given client
> talks to is unlikely to be the machine that data got sent to.  So
> you'd have to send the notifications from
>
> Client1 -> cassandra1 -> cassandra data node -> cassandra2 -> client 2
>
> It would complicate things significantly.
>
> -Jonathan
>
> On Fri, Sep 25, 2009 at 12:21 PM, Hector Yuen <hector.yuen@gmail.com>
> wrote:
> > Michael,
> >
> > What I want to do is to use a column as a place for keeping state between
> > different clients.
> >
> > I would register callbacks for a column, so when there is any other guy
> > changing the data I can get notified. That way I don't need to do
> continuous
> > polling.
> >
> > Is there any functionality right now that I could use to implement this?
> >
> > Thanks
> > -h
> >
> > On Fri, Sep 25, 2009 at 7:59 AM, Michael Greene <
> michael.greene@gmail.com>
> > wrote:
> >>
> >> Hector,
> >> Can you describe explicitly what you'd want to see from
> callouts/triggers?
> >>  One of the reasons I advocated for removal is that no one had a need
> for it
> >> or was working on it in the open source project.  What's your scenario?
> >> Michael
> >>
> >> On Fri, Sep 25, 2009 at 9:40 AM, Eric Evans <eevans@rackspace.com>
> wrote:
> >>>
> >>> On Fri, 2009-09-25 at 02:17 -0700, Hector Yuen wrote:
> >>> > I am just starting to use Cassandra, and I was wondering if it is
> >>> > possible
> >>> > to use triggers/ callbacks on columns so that they get notified when
> >>> > there
> >>> > is a change.
> >>> >
> >>> > Is there such functionality?
> >>>
> >>> No, there isn't. Someone was working on this at some point, but it
> >>> wasn't going anywhere so it got removed
> >>> (http://svn.apache.org/viewvc?view=rev&revision=806267).
> >>>
> >>> --
> >>> Eric Evans
> >>> eevans@rackspace.com
> >>>
> >>
> >
> >
> >
> > --
> > -h
> >
>

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