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HBase >> mail # user >> Can a RegionObserver coprocessor increment counter of a row key that may not belong to the region ?


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Amit Sela 2012-12-05, 12:35
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Asaf Mesika 2012-12-05, 18:56
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Amit Sela 2012-12-06, 07:28
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Andrew Purtell 2012-12-06, 07:40
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Amit Sela 2012-12-06, 08:05
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Re: Can a RegionObserver coprocessor increment counter of a row key that may not belong to the region ?
If you as a coprocessor are not writing back to your own region, you are
probably doing it wrong.

On Thursday, December 6, 2012, Amit Sela wrote:

> If I'm aggregating over the same Increment Object that triggered the
> Observer (the same key, same CFs but aggregating into different
> qualifiers), do I go outside the Region ?
> I know that for the cases I mentioned earlier I do but in the case I
> describe here don't I stay in the region ?
>
>
> On Thu, Dec 6, 2012 at 9:40 AM, Andrew Purtell <[EMAIL PROTECTED]<javascript:;>>
> wrote:
>
> > Summing/aggregating with a Coprocessor seems like a fine use, but it
> > should act upon only the data within the region to which it is
> > associated.
> >
> > However if it seems your Coprocessor must unavoidably update or access
> > data outside of its region, then either your schema design should
> > change (such that all data the coprocessor will operate on is
> > contained within the keyspace of the region); or, you should exclude
> > all possible client side options. For example maybe Datacube will work
> > for you here? See http://github.com/urbanairship/datacube
> >
> > On 12/6/12, Amit Sela <[EMAIL PROTECTED] <javascript:;>> wrote:
> > > I asked because I thought exactly what you all said but wanted to be
> > sure.
> > > My case is incrementing counters per URL where the families are time
> > > periods (hourly, daily...) and the qualifiers are
> > > impressions_criteria1,impressions_criteria2... I am going to use
> > > coprocessors in order to sum all impressions counters (all criteria
> > > segments) and then increment another counter (general count) that
> belongs
> > > to the same URL.
> > > Is that a good practice for Coprocessors (Observer) ?
> > >
> > > Thanks.
> > >
> > >
> > > On Wed, Dec 5, 2012 at 8:56 PM, Asaf Mesika <[EMAIL PROTECTED]<javascript:;>
> >
> > wrote:
> > >
> > >> Why not simply send Increment objects from the client side to HBase,
> to
> > >> the URL row key and to the domain row key?
> > >>
> > >> On 5 בדצמ 2012, at 14:35, Amit Sela <[EMAIL PROTECTED]<javascript:;>>
> wrote:
> > >>
> > >> > Hi all,
> > >> >
> > >> > I have to count the occurrence of URLs in our system using the URL
> as
> > >> > row
> > >> > key and using Increment.
> > >> > I also want to count domains, so I was thinking of using
> > RegionObserver
> > >> > coprocessor on postIncrement() and Increment using the domain as
> key.
> > >> >
> > >> > Will that work ? Is there a problem if the url key starts with
> 'www.'
> > >> > and
> > >> > the domain starts with 'aaaa' ?
> > >> >
> > >> > Thanks,
> > >> >
> > >> > Amit.
> > >>
> > >>
> > >
> >
>
--
Best regards,

   - Andy

Problems worthy of attack prove their worth by hitting back. - Piet Hein
(via Tom White)
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Amit Sela 2012-12-06, 13:42
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Asaf Mesika 2012-12-07, 08:15
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Toby Lazar 2012-12-06, 16:25
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Andrew Purtell 2012-12-07, 07:57
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Ted Yu 2012-12-05, 17:06
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Amit Sela 2012-12-05, 17:30
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Anoop John 2012-12-05, 17:58