Thanks for the help everyone. Would you see this as something that could be useful to ship with HBase? If so, I may well consider what I'm about to write a proof of concept and post again with my findings / the source.
On 7 February 2013 01:39, Michael Segel <michael_se...@hotmail.com> wrote: > I'd say add some sort of durable queue to receive the alert if you don't > want to miss a message. > > Essentially use a region server observer and write the alert to your > favorite pub/sub solution. > The key then is starting the pub/sub queue, first so that your region > server can connect to it. > > If you want to get fancy, there's a bit of overkill that you could do... > like figure out a way to write the output to HDFS if that made sense. > > Just some thoughts before I'm really awake... > > -Mike > > On Feb 5, 2013, at 10:45 PM, Andrew Purtell <apurt...@apache.org> wrote: > > > You are better off using your own RPC. Thrift would be a good choice. > > > > On Tuesday, February 5, 2013, Jan Althaus wrote: > > > >> Sorry for breaking the thread. It seems my subscription wasn't active at > >> the time the reply was posted. > >> > >> The client receiving the notifications would be a separate process, > >> potentially on a different machine. It could obviously connect to the > HBase > >> cluster though. > >> > >> I can certainly see how delivering such notifications would be outside > the > >> scope of HBase, but I wanted to make sure that I wasn't reinventing the > >> wheel by using a completely different RPC mechanism between the region > >> server and the servlet. > >> > >>> Please be a little more specific about where the notifications should > be > >>> received. > >>> > >>> Your custom RegionObserver lives on region server. > >>> > >>> I guess you want notifications to be delivered to your client, outside > >> the > >>> cluster. > >>> > >>> Cheers > >>> > >>> On Tue, Feb 5, 2013 at 12:18 PM, Jan Althaus <altha...@gmail.com > <javascript:;>> > >> wrote: > >>> > >>>> Hi, > >>>> > >>>> I would like to feed a servlet that is serving a long polling request > >> with > >>>> notifications when certain rows in an hbase table change. > >>>> > >>>> It seems that the best mechanism to achieve this would be to add a > >> custom > >>>> RegionObserver. What I'm unsure about though is how to best issue the > >>>> callback. Does hbase provide an RPC mechanism that I could re-use or > >> should > >>>> I consider this a separate problem entirely? Are there alternative > ways > >> to > >>>> get notified of row changes that better handle this problem? > >>>> > >>>> Thanks! > >>>> Jan > >>>> > >> > > > > > > -- > > Best regards, > > > > - Andy > > > > Problems worthy of attack prove their worth by hitting back. - Piet Hein > > (via Tom White) > >
