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Posted to user@cassandra.apache.org by Hector Yuen <he...@gmail.com> on 2009/09/25 11:17:53 UTC
triggers in cassandra
Hi all,
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?
Thanks
--
-h
Re: triggers in cassandra
Posted by Hector Yuen <hy...@alum.mit.edu>.
Michael
I will check that out
Thanks
On Fri, Sep 25, 2009 at 10:35 AM, Michael Greene
<mi...@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 <jb...@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 <he...@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 <ee...@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
Re: triggers in cassandra
Posted by Michael Greene <mi...@gmail.com>.
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 <jb...@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 <he...@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 <ee...@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
> >
>
Re: triggers in cassandra
Posted by Jonathan Ellis <jb...@gmail.com>.
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 <he...@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 <mi...@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 <ee...@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
>
Re: triggers in cassandra
Posted by Hector Yuen <he...@gmail.com>.
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 <mi...@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 <ee...@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
Re: triggers in cassandra
Posted by Michael Greene <mi...@gmail.com>.
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 <ee...@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
>
>
Re: triggers in cassandra
Posted by Eric Evans <ee...@rackspace.com>.
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