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From Arun Ramakrishnan <sinchronized.a...@gmail.com>
Subject writing coprocessor for custom types
Date Wed, 11 Jun 2014 02:48:03 GMT
I am experimenting with HBase to see if it would be a good fit for us. I am
just trying to build a poc. I am working on a standalone hbase on my local

 I was able to run 'sum' for a column qualifier whose values are Long. I
would like to be able to implement sum and similar operations for a custom

I was a little confused reconciling the examples in the hbase-book git repo
and the latest AggregateImplementation. Looks like the apis have changed
quite a bit. I am going to try and follow the code base pertaining to
0.98.3 . Unless, there is a good reason to use older versions.

Lets say we have a type Complex ( Just a simplified use case )

class Complex{
    Double real;
    Double imag;
    public Thing(Double _real, Double _imag){  this.real=_real; this._imag
= imag; }
    private Complex(){}

>From digging in, here are the steps I figured I have to do

1) class ComplexMsg
        I have not use protobufs before. I am stumped. Whats the easiest
way to get going here ?

2) class ComplexColumnInterpreter
       This seems more straight forward and plan to just take
DoubleColumnInterpreter and make changes to it.

3) Make these classes available on the region server classpaths.

Would this be all that is required ?  Would appreciate it if there is an
isolated example out there that can provide insight here.


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