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From Hector Yuen <...@alum.mit.edu>
Subject Re: triggers in cassandra
Date Fri, 25 Sep 2009 17:46:13 GMT
Michael

I will check that out

Thanks

On Fri, Sep 25, 2009 at 10:35 AM, Michael Greene
<michael.greene@gmail.com>wrote:

> 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
>> >
>>
>
>


-- 
-h

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