All,
<background>
I have a *map* which does some processing and then a *reduce* which sorts
the results.
TextInputFormat & TextOutputFormat are the input/output formats
respectively.
However the *sort* I want to perform is as follows:
I want to sort output by 'comparing' 'columns' of 'key's in the
Comparator and not the entire 'key'.
E.g. spec: column1, column0 is the sort-spec.
aaa ccc ggg
bbb aaa hhh
should result in:
bbb aaa hhh
aaa ccc ggg
</background>
I can't seem to find an 'elegant' way to do this via the MR framework i.e. I
can't seem to be able to set a *policy* (i.e. set the sort-spec) for the
WritableComparable via the framework. Is there something I'm missing? In
essence I probably need a *configure* callback for the WritableComparable
interface too? Is there a better way? Or is this outside the scope of the
framework.
thanks!
Arun
